Controlling Sky Color in Star Circle Images During the New Moon

This image was created using a technique I call time stacking. It is similar to taking a time lapse video over the course of a night, but instead of sequentially displaying each frame in a short animated video, I take the best parts from each exposure, and combine them in Photoshop using layers and masks to create the final image that is pleasing to my eye. It is a topic worthy of a separate post, which I shall write soon, but this post is about one small step in the process, in which I deliberately created the look of the sky you see in the image above during a new moon phase.

Original Star Circles Taken During Dark Sky

So here is the problem I was trying to solve (I have masked out the foreground for the purposes of this post, this is about the sky only).  The star circle layers I wanted to use consisted of 5 consecutive exposures, each @4min/f4.0/ISO400, taken during astronomical darkness. When the Blending Mode of these 5 layers are set to Lighten, you end up with a very dark, almost black sky. I like the way my chosen exposure settings rendered the star circles – bright, colorful, and at the density and intensity I find appealing, but I do not care for a black sky. How to lighten the sky? That is the question.

Sky Exposure Taken During Blue Hour

Here is one technique that I turn to often to control the color of the sky when I set out to create star circle images. Remember, I am essentially recording data to be put together in a final image later on, so as part of the process, I make sure to capture a sequence of exposures during the entire blue hour, just up until the time when stars become visible. So the series of exposures I have to choose from range from very light blue, to very dark blue. I just pick the one exposure that I like best, and include it in my image as a separate layer. as you can see in the screen capture above.

                      Blue Hour Sky Blended With Dark Sky Star Circles 
Now, if I set the Blending Mode of this new “blue hour” layer to Screen, you’ll see that the star circles remain nearly unchanged, but the color of the sky is now the “blue hour”color, as shown in the screen capture above.

Composite Sky Darkened By Reducing Opacity Of Blue Sky Layer

I like to select a “blue hour” sky exposure that is a bit lighter than what I envision for the final image. By doing this, I can dynamically change the lightness of the sky simply by changing the Opacity amount for the “blue hour” layer. In this case, I thought 40% Opacity looked the best.

So there you have it. Another tool in the arsenal of techniques at your disposal for controlling the look of your star circle images. Give it a whirl

My Night Photography Light Kit

One aspect of night photography that I really enjoy is the use of added light to achieve some desired outcome. One thing I have discovered is that if you get bitten by the night-lighting bug, the result is usually Gear Acquisition Syndrome, in which every type of light source becomes an object of desire. I will attempt to show you how it has affected me, in this round-the-kitchen-table style post regarding my light kit.

Utility Working Lights

Key Chain LED Light

I’ll start with my most used and cherished light. That’s right, this tiny key chain light. You probably have one sitting in your kitchen junk drawer (everybody has a junk drawer, right?). And why is this my favorite light?

Well, my friends, I am about to tell you a hard truth, something your best friend might hesitate to tell you for fear of hurting your feelings. Do not be “that guy” (to my friends of the female persuasion, feel free to substitute “that gal”). You know who I’m talking about – “that guy” who approaches you with a question and has his headlamp shining right into your eyes, “that guy” who fishes a 2000 lumen flashlight from his bag and lights up the entire county in order to change a setting on his camera, “that guy” who has read an astronomy magazine article about how red light preserves night vision, so now all of your images have his red light bleeding into all of your images (see this article on the Night Photography Workshop blog about the evil of red lights). “That guy” never gets invited to go shooting with others again. So don’t be “that guy”.

I have two of these small, inexpensive key chain lights attached to a lanyard that goes around my neck as soon as I start setting up my gear for the night. One is wrapped with gaffers tape to dim the light to a small, focused beam. It is perfect for adjusting settings or looking at degree markings on a panoramic head. Just bright enough to read markings, but dim enough that it does not bother other photographers around you. The second, unwrapped and brighter LED key chain light, is great for looking through your camera bag or checking your surroundings, again, without bothering others.

It is amazing how little light you really need to accomplish your night photography tasks, once you become familiar with handling and adjusting your equipment in the dark.

These little lights are so cheap that I buy them in bulk, and pass them around freely whenever I am shooting at night with others. It saves a lot of hard feelings, as well as images. Hopefully, I will have prevented someone from inadvertently becoming “that guy”.

LED Head Lamp

The next light that I always have with me on a night shoot is my headlamp. When I am shooting by myself I use my headlamp freely, however when shooting along with others, I rarely use my headlamp outside of hiking from my vehicle to the shooting locale and back.

I use the Nitecore HC90 headlamp shown above. This headlamp has many important features that I have grown accustomed to. It has a maximum brightness of 900 lumens, which can be very handy when negotiating trails at night, or other times when you absolutely must have a bright light at hand. But what I like the most about this headlamp is that it can be turned on to its least powerful setting, .2 lumens (that’s right, POINT 2 lumens) instantly and conveniently, so you can use this headlamp in a responsible manner, and not blind your shooting partners. The headlamp is rugged and heavily built, and operates with a single 18650 lithium battery. It is rechargeable either by removing the battery and placing it in a separate charger, or by plugging it directly into a USB charging source. In addition to the variable intensity white light, this headlamp includes red, blue, and green LEDs, which are activated by the sliding switch. I rarely have reason to use the RGB LEDs, so I generally cover the LED’s with gaffers tape so I don’t accidentally turn them on (and become “that guy”).

High Intensity White Lights For Light Painting

Small 460 Lumen All Purpose LED Flashlight

There are times when a key chain light or a headlamp will not provide the light you need for light painting a scene. For this you need other tools (although a headlamp can sometimes be used in a pinch). My smallest, least powerful hand-held flashlight is the Nitecore EC21 shown above. It has a maximum brightness of 460 lumens, but still dims to 1 lumen, and has a built-in red LED. It is powered by a single 18650 lithium battery. When the power is locked off, the flashlight indicates the remaining battery capacity. It is simple to turn the light on and off, but there is no momentary on, just a toggle for on/off. For some light painters, this is an issue. I have other flashlights with momentary on when I need that feature, so it is not important for me that this particular flashlight lacks this ability.

Mid-size 2000 Lumen Bright LED Flashlight

Next up is a hand-held flashlight that I love for various reasons. Pictured above is the Nitecore P36, a workhorse that is a tool I reach for often. It has a maximum brightness of a blinding 2000 lumens, very useful when you are deep in the woods some night and you are sure you just heard Bigfoot rustling in the nearby trees! And yet, with amazing speed and simplicity, it dims down to 2 lumens, with a total of 10 steps of adjustment. It is equipped with a dual on-off switch. It will toggle on and off, or function as a momentary on button. It is a simple and intuitive design. Because of the high power this light is capable of producing, it is important to pair it with sufficient energy. This flashlight is powered by 2 x 18650 lithium batteries, to provide ample power for many nights of photography without having to recharge.

P36 LED Flashlight With Snoot

This is the same Nitecore P36, but fitted with a home-fashioned snoot. A snoot is useful to narrow the beam of a light source. I have made snoots of various lengths for each of my lights. and choose which to use based on the needs of each different scene.

It is useful to bring up the issue of color temperature at this point. The three Nitecore lights I have shown you are each equipped with a different type of LED bulb, ranging from very cool to very warm.

The image above clearly illustrates the color temperature difference between the various CREE LED bulbs. Notice that the Nitecore P36 flashlight, equipped with the warm CREE MT-G2 is my workhorse light for lightpainting. This is one reason why. For more on this topic, see my post entitled “All LED Bulbs Are NOT Created Equal”.

Here are some examples of images made using light painting techniques with these Nitecore lights:

High Contrast Texture Added To Foreground

Here the exposure was set to capture star circles with the full moon illuminating the terrain, balanced with the P36 set to low brightness to illuminate the wheel, then quickly set to high brightness to provide high contrast lighting to the sagebrush. So there are actually three light sources here – the moon, the P36 at low intensity, and the P36 at high intensity. All in a single exposure.

High Contrast Texture Added To Foreground

The Nitecore P36 was used in this image in a similar way. This is a single exposure, with the P36 used at first in its lowest setting to paint the stone wall, and then quickly switched to high brightness to accentuate the sagebrush. The length of the exposure was limited by the desire to create pinpoint stars.

High Intensity Colored LED Flashlight For Light Painting

ProtoMachine LED2

This is the ProtoMachine LED2. It is a tool developed specifically for the purpose of light painting. It is being marketed in its current configuration as the ProtoMachine LED8, similar in most functionality, but with a few updated controls. This light can be set to produce the entire HSL light wheel, and allows for eight user customizable presets, so you can quickly recall pre-selected colors at will.

ProtoMachine LED2 Control Panel

The control panel on the back of the ProtoMachine LED2 light, showing the buttons and joystick used to set the desired lighting.

ProtoMachine LED2 With Snoot

The ProtoMachine LED2 fitted with one of my home brewed snoots. I have created snoots of various lengths for all of my lights, and use the length necessary for the task at hand with each shoot.

Here are some examples using the ProtoMachine LED2 to add color to an image:

Lake Painted Blue with ProtoMachine LED2

I was quite surprised to see that the color of Table Rock Lake turned a brilliant shade of blue by illuminating the water with the ProtoMachine LED2 set to a nice shade of blue for about 2 minutes.

Big Bridge Over Cricket Creek

This is a good example to show the distance the ProtoMachine LED2 will throw a beam of light. The underside of these Highway 65 bridge spans were painted with the LED2 set to about 70% output

Painting Color On A White Automobile

.An image showing the addition of color from painting a white SUV with various shades of reds and blues from the ProtoMachine LED2.

The Tractor From Hades

I wanted to achieve a “tractor from Hell” look to this image, so I used various shades of orange from the ProtoMachine LED2 to light paint the tractor.

Low Level Lighting

Low-Level Lighting (LLL), sometimes referred to as Low-Level Landscape Lighting (LLLL) is a method of lighting the foreground elements of an image through the use of a very dim light source kept on for the duration of the exposure. The light level is adjusted to the same intensity level as the stars or Milky Way, thus ensuring that an exposure that works for the sky will also work for the foreground. Once the lighting levels have been properly balanced, the low-level lights can remain on without further adjustment for the duration of the shoot. It makes simple work of ensuring consistent lighting in exposures for work requiring multiple captures to produce the final image.

I should note that Low Level Lighting also includes moonlight! The moon is the most wonderful tool available to the night photographer. It is such an important aspect to night photography generally, and astro-landscape photography in particular, that I shall offer my thoughts in a separate post. For now, I’ll just talk about artificial light sources.

F&V Z96 Warming, Milk White, and Diffusion Filters

I have been using three of these F&V Z96 Light Panels for about 2 years, and find myself using them regularly. This LED light panel consists of 96 LED bulbs that allow for brightness adjustment via a dial on the rear of the body.

The light comes with 2 filters – a warming filter and a diffusing filter. I have found a third filter, the F&V Milk White Diffusion Filter on Amazon. I have found that I rarely have to turn the light intensity up beyond the absolute minimum in order to get properly balanced lighting. In fact, I usually have to dim the light further, and find the Milk White filter reduces the light output considerably. This can be a real convenience when it is difficult to move the lights further from the subject, and they are already turned down to their dimmest setting.

F&V Z96 powered by NP-F970 Li-ion battery

There are three ways to power this light. I use a NP-F970 Li-ion battery, which will last for several nights without needing to be recharged. The downside is the size and weight of the battery. Alternatively, the light can be operated with AA alkaline batteries instead.

F&V Z96 powered by (5) AA alkaline batteries

There is also a receptacle for a 12v power supply, which I never use.

F&V Z96 rigged with a lower barn door shade

The F&V Z96 LED light panels tend to spill a lot of light downward, which may sometimes interfere with the intended shot. I this case, I have found that improvising a barn-door shade that fits between the LED Panel body and tripod/light stand works wonders. It is light, easy to fabricate, and packs easily.

Manfrotto Tripods and Joby GorillaPods

I use Joby GorillaPods and Manfrotto compact tripods as light stands for my LED light panels, as well as my Yongnuo Electronic Flash units (more on these later in this post). I have been asked why I carry three LED light panels, as well as light stands around. Do I really need all three? Here are some examples where three lights came in handy.

One panel for left-front, one for right-side, and one for second structure

Here is a shot that required three exterior lights. One was set up to illuminate the left hand side of the church, including the doorway. A second panel was set up to illuminate the side of the church, while a third light was set up to illuminate the schoolhouse structure in the background.

Three Z96 LED panels spread out to illuminate the tree line

In this image there would have been no easy way to illuminate the entire line of trees down the length of this highway without the help of three LED light panels (I know that one could take a single LED panel and walk up and down the roadway shining the LED panel up at the trees, and do this repeatedly for a long time, hoping to not get run over in the process, but PLEASE – I’m an old(ish) man!!

I could include other examples, but the point is, more light panels mean more opportunities. And while not absolutely necessary, they can be helpful when contemplating a night composition.

Other Fun Lighting Gear

The Pixelstick

The Pixelstick is a digital light painting tool that has several modes of operation, and allows the photographer to express their artistic sensibilities in various ways. I have only owned a Pixelstick for a short time, so I do not have a great amount of experience with it, other than the basics that I have experimented with to date. At first glance, however, I can see that this is going to be a lot of fun, as well as challenging my creativity.

Pixelstick in storage case (shown broken down for transport)

Pixelstick Controller Module

The controller assemble of the Pixelstick is the brains behind this device. It accepts SD cards to store bit mapped image files, which it then projects on its integral LED bulbs. The menu system built into firmware allows the parameters of the current project to be programmed and stored.

The Pixelstick is taller than I am when it is completely assembled. It is a light painting tool that consists of 200 LED bulbs, with each bulb independently addressable and capable of producing the color spectrum at a variety of intensities. It can effectively project an image consisting of vertical pixels, that when transported across the field of view, creates an image. Although I have not used the Pixelstick extensively, I have a few examples to show what a few of its capabilities are.

Front lawn on fire

In this image, I used a stock bit map image of flames to create this scene. I set the Repeat mode on and proceeded to walk around my yard and up and down the road in front of the house to create an illusion of flames. This was all done while the camera shutter was open for a long exposure.

South Moulton Barn in the Ozarks

In this image, I took a photograph of the South Moulton Barn, which is located in Grand Teton National Park in Wyoming, and uploaded it as a bit map image to my Pixelstick. By walking across my front lawn while projecting this barn image from the Pixelstick, I was able to create the illusion of the barn being in the Ozarks. The waviness exhibited in the barn is due to my lack of practice in developing a smooth, gliding gait while carrying the Pixelstick. Practice should remedy this shortcoming in the future.

And finally, here is my attempt to place an armadillo in my campsite while on a trip to Kansas. All in all, I am looking forward to seeing what I can come up with using the Pixelstick over the next year or so. I fear the capabilities of the Pixelstick will greatly surpass my creative imagination. We’ll see.

Multi-function mini lanterns

These inexpensive mini lanterns have proven to be very useful in many situations. They are small, readily available, and cheap. Here are a couple of examples of the mini lanterns in use:

Mini lanterns simulate glowing embers

When I went to the Cricket Creek Public Use Area last year to shoot some night sky photographs, the Army Corp of Engineers had bulldozed some driftwood into a big pile on the beach right where I planned to set up my tripod. Rather than fret, I set up three of my mini-lanterns in the pile of driftwood, and turned them on to the red mode. It simulated the look of embers glowing from a fire, and created some interest in the foreground that otherwise would have been plain and barren.

Mini lantern illuminating cemetery monument recess

A single mini lantern was used to illuminate the recess in the cemetery monument located at the entrance to the Terlingua Cemetery in Texas.

Mini lanterns illuminating the interior of this SUV

Also in Terlingua, Texas, two mini lanterns were used to light up the interior of this SUV, which adds a nice contrast to the mural painted on the side of the vehicle.

Various Tea Lamps

Tea lamps are small, low intensity, inexpensive lights that are useful for illuminating tents, windows, and other items in a night scene. I always keep a few in my gear bag, as you never know when they will come in handy. I have two kinds, as seen above.

The lights in the top of the photo are multi-colored and multi-intensity, Flameless LED Tea Lights. They are remote controlled, so that the intensity can be adjusted from a distance. This is useful if setting the lamps up in an enclosed space, such as a tent or automobile. It allows the light intensity to be easily balanced with the ambient light conditions.

The lights in the bottom of the photo are Floral Submersible Tea Lights, which are cheap, small and useful in a variety of situations.

Tea lights illuminate interior of tent

Tea lights can be used to illuminate a variety of subjects, and are often used to illuminate the interior of a foreground element, such as this tent.

Tea lights illuminate interior of Cunningham Cabin

Tea lights are very useful to illuminate the interior of buildings and cabins that are the subject in a photograph. The additional lighting effect adds interest to the foreground and sets it apart from the sky.

Yongnuo YN-560IV with remote trigger

The Yongnuo YN-560IV Wireless Flash Speedlites with LCD Flash Trigger Remote are inexpensive flash units that can easily be transported in ones lighting bag for use in night portraiture, or whenever the photographer want to freeze motion in an image. The remote controller allows easy adjustment of the speedlite output without having to move to each flash position for adjusting. All adjustments are made right from the control unit, which can be mounted on the camera or carried in hand.

Here are two examples of images made using the Yongnuo speedlites for a selfie type portrait taken during a long exposure.

Pondering the Fireflies in Maine

Pondering the heavens in Arkansas

Both of the photographs above include yours truly in the image. I used the Yongnuo speedlites to ensure a motion free selfie, which I blended into the long-exposure foreground to add a little interest to an otherwise ordinary photograph.

Flare Buster mounted to tripod

Lastly, I will present this device called a Flare Buster. It is actually more of an ANTI-LIGHTING device than a light per se, but I am including it here because it is an offshoot of the lighting decisions we make as night photographers. After reading about devices similar to this in Lance Keimig’s fine book, Night Photography and Light Painting, Second Edition, I searched far and wide for a device like this. I finally found it at B&H Photo, and it is called the Extra Long Flare Buster Kit.

Image made possible with use of the Flare Buster kit

This is an image I tried making before owning the Flare Buster. In my previous attempt, the image was rendered unusable due to a giant distracting flare that was created by the glare from the marina lights, just outside the frame on the right of the image. On my next outing to capture this scene, I was prepared with the Flare Buster Kit, and it did the trick. I was rewarded with this shot.


There are many types of lights that can be used in the pursuit of night images. Some are general purpose tools, used frequently by night photographers, and some are more specialized, coming out of the gear bag only occasionally. Whichever methods and devices you use to create your night images are limited only by your imagination, and the lighting equipment you have at hand. In any case, added lighting is a fun dimension to add to your night photography repertoire.

Sigma 20mm f1.4 Art Series Lens For Night Photography, An Alternative View

My “go to” lens for astro-landscape photography used to be a Rokinon 24mm f1.4 manual lens. It seems to be standard advice given out within various night photography groups and publications that the Rokinon 24mm f1.4, along with the Rokinon 14mm f2.8 are the standard for budget minded photographers who want to photograph the Milky Way. After using these lenses for a couple of years now, I have come to a different view, and have been updating my lens collection accordingly. The lenses I have been migrating toward are the Sigma series of Art lenses, specifically the Sigma 20mm f1.4, Sigma 24-35mm f2.0, and the Sigma 50mm f1.4. Since my switch, I have been asked repeatedly about my reasons for the switch, and my impression of the Sigma vs. Rokinon performance. Rather than responding with the same answers multiple times, I am writing this post so that I can simply send a link to the post, and all who ask will get the same uniform response.

First, a disclaimer. I am, by no stretch of the imagination, an expert on lens performance, nor do I possess the necessary experience to opine generally on this topic. But I do feel I can contribute some constructive observations on the lenses in question based on my own particular usage and expectations thereof. So in this spirit, here are my thoughts. As always, YMMV.

The first consideration is cost. Looking at Amazon or B&H, one quickly finds that the Rokinon series of lenses costs roughly half of what the Sigma lenses retail for, some slightly more, some slightly less. If cost were the only consideration (or perhaps the major consideration), the Rokinons would win hands down. On the other hand, if longevity is a consideration, the Sigma lenses come out ahead. The quality control of the Sigma lenses has proven to be excellent in real world use, while the Rokinon lenses are build to a less rigorous physical standard. Additionally, there are many Rokinon users that report having to return Rokinon lenses because of an issue of decentered lens groups, leading to half of the image being out of focus. I have had to return two copies of my Rokinon 24mm before receiving one that was not decentered.

The Rokinon lenses are fully manual lenses, while the Sigma lenses are automatic. The standard story line is that we shoot in manual mode when doing night photography, so it does not matter that the Rokinon lenses are manual. Phooey!! Maybe for you it might not matter, but for me it has become a deal breaker, and here are my reasons why.

1) On a fully manual lens, the EXIF data recorded with the RAW image file (or JPEGS, for that matter) does not contain information on the lens that was used in the shot, nor the f-stop that was used to produce the image. Try going through images you took a month or year ago, and see if you can identify the lens used or the aperture. The same people who advise that a manual lens presents no problem for night photographers seem to contradict themselves, when in other contexts they recommend comparing coma testing results to see what settings are acceptable in actual use. How can you compare the results of two or more exposures, when the EXIF reads f(???) and f(???). Also, has anyone ever asked you what exposure settings were used to create an image, and you had to guess because there is nothing regarding aperture in the EXIF data? How about lens focal length? Are your observational skill sufficiently developed so at a glance you can determine whether an image was taken with a 14mm, 20mm, 24mm or 35mm lens just by examining an image? Mine certainly are not, and I do not like to guess about these settings when examining and critiquing past images.

2) On a fully manual lens the aperture must be set with a ring on the lens barrel. I shoot at night here in the Ozarks as a regular routine, and also in other locations where the temperature and dew point converge. To eliminate fogging, I must wrap the lens barrel with a dew heater or with hand warmers to prevent fogging. This means that I must unwrap the lens to make any aperture adjustment and then re-wrap the lens. Try doing this repeatedly in the course of a shooting session without disturbing the focus or camera positioning – it is difficult, if not impossible. An automatic lens solves the problem. Just adjust aperture using the control dial. No need to unwrap and re-wrap the lens any more!

And now to the main issue most people are asking me about – image sharpness and coma. The Rokinon lenses have a well deserved reputation for being lenses that minimize coma (I’ll use coma here as a proxy for coma and astigmatism). Even when shot wide open, the Rokinons perform exceedingly well in the coma department, much better than the Sigma lenses, which need to be stopped down to achieve the same coma performance. HOWEVER, the Sigma lenses have a well deserved reputation (confirmed on test benches) for incredible edge to edge sharpness throughout the Art Series lineup. Refer to DxO testing and MTF charts to compare the difference between the Rokinon and Sigma lenses. The Sigma lenses win hands down in this regard. While I admit to not having experience with many high-end lenses such as Zeiss or Sony GMaster lenses, I have been truly astounded with the overall sharpness of my Sigma lenses. The sharpness extends from edge to edge, not just in the center, as in the Rokinon lenses, which also appear to be softer in general than the Sigma lenses.

With regard to the Sigma 20mm f1.4 specifically, I have a different view than most when comparing it to the Rokinon 24mm f1.4. When shooting a single frame image (non-pano), if I crop the image to the same field of view as the Rokinon 24mm, the coma affected stars are cropped away, but I gain the advantage of the stunning sharpness of the Sigma compared to the Rokinon, while achieving essentially the same field of view. When I shoot for a panorama, as long as I provide sufficient overlap (I overlap 50%) the coma affected stars are not included in the stitched image, except in the extreme outer edges, which is easy to correct in post processing.

And my last observation regarding the Rokinon vs. Sigma debate. In daytime shooting, the Sigma lenses produce results that are rated among the best lenses. And they are fully automatic, to boot. By giving a little forethought to how I use the lenses at night, I can get the best of both worlds (daytime and nighttime) with the Sigma lenses.

I believe that the photographer should take into consideration the type of night photographs they wish to create in making the decision on which lenses to acquire. My own style is evolving to emphasize the foreground, and reduce the sky as the main element of the image. In this regard, the Sigma lenses excel, especially as compared to images I have taken with my Rokinon lenses. Please feel free to comment with your own experiences with these, or other lenses. I’d love to hear from you!

A Scouting Trip To Kansas


Night photography in the Ozarks can be difficult. The narrow, winding, dark roads are hazardous to drive at night, and the abrupt falloff from lane edges to drainage ditches means there is usually no shoulder to park alongside the roadways. While there are areas in the Ozarks with dark skies, most of these areas are quite inaccessible (there are good reasons why the Ozarks remained a “semi-arrested frontier” for generations, the ruggedness of the terrain being one of them). Combine this with the warm and humid air of the region, which creates lots of long exposure noise in images, and one can see why night photographers in the region are always on the lookout for alternate locations to shoot.

That is why, when Darren White posted an invitation to his friends to join him on a photographic scouting trip in Kansas recently, I immediately jumped at the opportunity. Not only does Kansas have reasonably dark skies, it also features many wonderful foreground subjects with easy access and wide-open horizons. And shooting with Darren is always inspirational and educational. What could possibly go wrong? Besides the weather, which rained or created foggy skies most of the trip. Besides the electrical system going out in my RV. Besides the water pump in the RV dying. Besides the hundreds of pounds of mud I pressure washed from every nook and cranny underneath my truck. These were merely annoyances compared to what I gained by participating in this scouting trip.

While I do not have many night images from this trip due to the weather, we did manage to explore a trove of locations that will provide many, many night images in the future. Meanwhile, the photography I did manage to get in turned out OK, so I thought I would share some of the images and locations through this post.

Day 1 (Wednesday) and Day 2 (Thursday)

Day 1 was spent driving from the Ozarks to Cedar Bluff State Park, located at Cedar Bluff Reservoir in central Kansas. After a long rainy drive, I spent the night making repairs to the RV and resting up for the following day. On Day 2 I met fellow photographer Mike Spivey at a location near Dubuque, Kansas, where we awaited the sunset in order to photograph this old church and schoolhouse, The sunset did not disappoint, and we were rewarded with some rich, warm tones to work with. It was here that we met Derek Ace, a photographer from Wisconsin, who joined us in shooting these structures.

Derek had just arrived in Kansas after a long drive from Wisconsin, so he departed immediately after sunset to catch up on some needed rest, while Mike and I continued to shoot the old abandoned church until about 11:00 pm. It was pretty apparent that the Milky Way would not be making an appearance early the next morning due to the clouds, so I made my way back to camp at Cedar Bluff State Park.

The sky decided to play tease with me – when I arrived back in camp, the clouds had completely disappeared, so I set up the camera to take star circles around this giant fishing rod & reel for a couple of hours, while awaiting the Milky Way core, which would be rising in the wee hours of the morning. I settle down in the truck to take a nap, and when I awoke, the area was engulfed in fog. No Milky Way again.

Day 3 (Friday)

Several photographers met up on this, the first “official” day of the scouting trip, at 4:00 pm at Cedar Bluff State Park in central Kansas.. Included were Darren, Bob, Mike, Angie, Shari, and myself. Our first order of business, after getting acquainted, was to explore both the south and north shores of the Cedar Bluff Reservoir. The south shore is generally flat, but contains areas full of the trees that stick up out of the water. The north shore, on the other hand, has nice areas of rocky bluffs that are quite rugged and photogenic. I think that the Cedar Bluff area has great potential for night images when the sky and weather are cooperative.

Day 4 (Saturday)

Our intrepid group of explorers departed camp at 5:00 am, hoping to catch the sunrise at the Excelsior Lutheran Church, a beautiful structure near Wilson, Kansas, located in the middle of the Smokey Hills Wind Farm. The rains of the previous night and that morning made the roads too muddy for some of the vehicles in our caravan, so we toured around the area instead. Some locals informed us of a couple of attractions nearby, so off we went to check them out. Above is a view of Wilson Lake, near Wilson, Kansas. It has a reputation as a great bass fishing lake, and appears to be a location where the Milky Way might be captured, given the right conditions.

After visiting the towns of Lucas, Kansas (home of the wonderful Garden of Eden) and Wilson, Kansas, we headed over to Ellsworth, Kansas. Our group of photographers (now whittled down to four, as two opted to return home on account of the rain) explored around town, where it is apparently a thing to photograph grain elevators with leading lines from railroad tracks :)

Because of the extensive rains that had occurred, there were puddles everywhere, so what better time to practice my puddleography skills using my cell phone camera.

Continuing on from Ellsworth, we explored Fort Harker, Lyons, Ellinwood, Great Bend, and Ness City before heading back to base camp at Cedar Bluff State Park. There were several abandoned structures along the route, and I compiled a decent list of night photograph possibilities for future trips in my PlanIt! for Photographers Pro software.

Day 5 (Sunday)

One more member of our group, Shari had headed home Saturday, so now there were just the three of us left, Darren, Bob, and myself. We decided to meet up for sunrise at 6:00 am Sunday morning to photograph the Wilcox School, about 15 minutes south of Wakeeney, Kansas. The sun was not very cooperative with our sunrise plans, so I attempted a few “faux fog” shots of the schoolhouse, which Darren had just taught me. What I learned is that I had wasted my money buying a Tiffen Double Fog 3 Filter. Just breathing on the front lens element provides a far better result, and you can look through the live view and snap the shutter when the fog effect is just to your liking. An interesting technique I will certainly employ from time to time in the future.

It was now time to head over to Monument Rock and Chalk Pyramids for some daytime shots of the area, but not before stopping to look at some interesting sights along the way. At the Scott County Fairgrounds, in Scott City, Bob and I were at a loss to explain the reason for this gate. It reminded me of the scene in Blazing Saddles, where the army of bad guys stop in the middle of the plains to pay a toll at an isolated toll gate!

As a reminder of how transitory some subjects can be, here is a shot taken on another of the trips to Kansas that Darren was so kind to organize in August of 2016. A group of four photographers (including myself) spent hours at this old abandoned grain shed located on Jayhawk Road as lightning storms raged all around us. The photo opportunities that night were beyond amazing, and while I know that was a stroke of luck not likely to be repeated, I was still looking forward to photographing from this location again. Alas, we discovered as we drove past this structure that the roof, with the beautiful overhanging eaves, had collapsed! Oh well, I’m just glad I had the chance to photograph this building when I did.

At this point, I would like to have said that I took these images on this scouting trip to Monument Rock and Chalk Pyramids, but when Darren contacted them they informed him the area was unavailable for special permission to photograph at night, due to calving season. This wonderful geographic feature is located on private property, and the owners have been quite generous in allowing the public to enjoy the area. The rules that are posted are simple to comply with, and if you contact them beforehand, they will try to accommodate your visit request if at all possible. I urge you to do your part to help keep Monument Rocks available for all of us to enjoy in the future. 

I was extremely hopeful to get a Milky Way panorama over Monument Rocks this trip, but due to circumstances beyond my control, I could not. So I faked one using a composite of a foreground panorama taken on this trip to Kansas, and a Milky Way sky taken last year in Wyoming. I’m allowed to imagine, aren’t I?

After photographing Monument Rocks we headed off to explore some of the small towns along Old Highway 40. In the town of Park, Kansas (population 129) we discovered a Catholic Church that I’m sure could easily hold 10 times the population of Park. This seems to be a common feature in small Kansas towns – huge churches relative to the size of the town.

From Park, Kansas we continued on to the town of Collyer, where the main attraction seems to be the Pontiac Bar and Grill, even though it is currently out of business. It must be sorely missed, because, as Darren has pointed out, four locals inquired (hopefully) as to whether we were there to buy the bar! In case you were wondering, the other half of the Pontiac (it looks to be vintage 1953) is mounted on the rear of the building.

After finishing up in Collyer, we headed back to Ransom, Kansas to shoot sunset pictures of the old schoolhouse that we had visited earlier in the morning. Near the school was an old abandoned homestead, which included some interesting finds, such as the old vehicles scattered around the property.

We enjoyed some nice glow from the sunset, and it provided us with some really nice light to work with the schoolhouse. After sunset we headed back to Cedar Bluff State Park, where we intended to nap and await the rise of the Milky Way core early in the morning hours.

Rather than napping, I decided to try out a new (to me) light painting device called a Pixelstick. All was well, until this giant armadillo chased my into my camper for the night. When the alarm went off at 2:00 am to signal that it was time to go shoot the Milky Way, I popped my head out the door and discovered that fog had completely enveloped the area. Darren and Bob decided to start heading for home, and I decided to get a good night of sleep. The next morning I checked the weather forecast, and it wasn’t looking good, so I decided to head on back to my neck of the woods in the Ozarks.


All in all, it was a successful trip. I did not get any of the Milky Way photographs that I had hoped for; in fact, I did very little night photography on account of the weather conditions. But the purpose of this trip was to scout out areas of Kansas that might be conducive to night photography at some future date, and on this count, the trip was very successful. I have shared some of the sites we visited, but have saved some of the best for later, when I can go back and photograph them the way I envision the scenes in my head. Meanwhile, it was a fun, if not tiring trip, and I met some interesting new friends to boot!


How I Learned To Love NIK Dfine

To my knowledge, there is no better way to reduce or eliminate high ISO random noise in a night sky image than to align and stack multiple exposures and apply noise reduction through some form of median stacking.  Having said that, I would like to reduce high ISO sky noise at times when I didn’t take multiple sky exposures, for whatever reason. I have used the noise reduction tools in Photoshop, Lightroom and NIK Dfine, and (in my hands, at least) found the results from each so similar that I would default to Adobe for noise reduction, either in Lightroom or Photoshop.

In re-editing the photo above, I thought it would be fun to experiment with a possible noise reduction technique that had been bouncing around in my head for a few months. Here is the gist of what I wanted to accomplish.

Suppose the small white, yellow and magenta dots represent the stars in the sky. Now imagine that the three vertical bars (light blue, medium blue and dark blue) represent the range of tones comprising the noise.

As the first step I created a luminosity mask to mask out the “stars”.

The second step is to create a solid fill layer (sampled to the medium blue bar), and set the blending mode to lighten. Since I have set this as a clipping mask, the “stars” are unaffected. Notice that the dark blue dots and dark blue vertical bar have disappeared.

In this third step I have created another fill layer sampled to the same medium blue as before, but set the blending mode to darken. I have also set this as a clipping mask. Notice that the light blue dots and light blue vertical bar have disappeared.  Notice also, however, how flat the “sky” background has become without the “noise” to provide texture.

In this fourth step I reduced the opacity of each of the two fill layers to 85%, just enough to allow some of the “noise” tones back into the image, so that it doesn’t look quite so artificial.

Applying this technique to a somewhat noisy image of a pinpoint star field, I came up with results that looked pretty good for a first attempt. I posted this sample on Facebook to see what others might think, and got some positive, but mixed reactions. I decided to prepare a blog post to detail what I was working on for further comment, and it started like this:

This is a single exposure of a spot near Oakley, Kansas taken at ISO 6400 for a duration of 10 seconds. It is a respectable image for screen viewing, but is not a great candidate to print at any appreciable size due to the amount of noise created at ISO 6400, even shooting with a Sony A7Rii, which performs very well at high ISO settings.

At 100% viewing the noise problem becomes apparent, both in the sky and in the foreground.

Here is the foreground in the ISO 6400 exposure magnified to 200%. Note the amount of random noise. If I were to reduce the ISO from 6400 to ISO 200, random noise would be reduced, but I would also have to lengthen the exposure time to compensate. Increasing the exposure time would cause the stars to trail in the sky. The solution to this problem is to blend two separate exposures, one taken to optimize the pinpoint stars (remember, we are not stacking sky exposures for the purposes of this post) and one taken to optimize the foreground.

This is a 6 minute ISO 200 exposure magnified to 200%. Notice how clean the rocks appear. But the six minute exposure will not work for pinpoint stars, so I blended this clean ISO 200 foreground exposure with the noisy ISO 6400 sky exposure, in the hope of reducing the random sky noise later on in the process.

By creating a layer mask in Photoshop I could blend the clean foreground with the noisy sky.

As you can see above, this left me with a very clean foreground, but the sky is still quite noisy. As I was originally writing this post, this is where I was going to demonstrate my experiments with alternative noise “mitigation”.

First, I created a luminosity mask to protect the stars from my manipulations.

Second, I created two solid fill layers, each one sampled to a middle tone I chose from within the red square above. As in my demonstration with the blue dots and blue vertical bars, I set one layer to lighten blending mode, and one layer to darken blending mode, and set the opacity of both to 85%, to retain some graininess.

This is the result, shown at 100%. I was pleasantly surprised when I saw how well this procedure worked, well beyond anything I had anticipated. The stars are still the same sharpness as before the process, their colors remained steadfast, and the noise significantly reduced.

Before rushing to post the results of my experiment, I decided to try the technique out on a few of my other images, to see what would happen.

OH, the HORROR, the HORROR of it all. I won’t torture you with the results. Let’s just say, any changes in coloration or tonality across the sky renders this process useless. Unless you want to purposely convert the beautiful nuances of the night sky into a uniform, flat, dull, lifeless… get the picture.

For this procedure to have any hope of working, I would have to devise a way to apply fill layers though some type of gradient map that takes account of the tonality and coloration throughout the sky. Guess what? My research into creating the kind of gradient map I was looking for somehow led me right back to NIK Dfine.

It came to my attention that NIK Dfine had already tackled this problem in a very elegant way, only I was unaware of this capability, or how to tap into it. Apparently, I was attempting to invent the wheel, except that Google had already invented it, plus provided it with shiny new hubcaps, as well!

It turns out if you dig into NIK Dfine you can find some powerful functionality that does a far better and more comprehensive job of doing what I was attempting with my layer masking method of noise reduction. By tapping into the Manual mode, rather than the default automatic mode, and then choosing the Color Ranges mode, one can create customized noise control points specific to a particular image. If you examine the screen capture above, you will see two sets of Color Range controls I have created. For the upper three Color Range controls, I have used the eyedropper to sample dark, middle and light tones from the darkest region of the sky. For the lower three Color Range controls, I have created a set of controls to sample dark, middle and light tones from the lightest region of the sky.

Notice that in the upper three Color Range controls, which represent the darkest region of the sky, I have boosted the intensity of the Contrast Noise slider to 110%, under the logic that I can be a little more aggressive with noise suppression in the darker ranges than I can in the lighter ranges.

In the bottom three Color Range controls, which represent the lighter regions in the sky, I have reduced the intensity of the Contrast Noise effect to 90% in the lightest of the controls, under the logic that I want to be highly protective in the detail of the stars.

Using the Contrast Noise Sliders attached to each control range, combined with the Luminance Viewing Mode (found in the upper left), allowed me to visually adjust the noise reduction that was being applied through each Color Range, and I could be as aggressive or conservative in the noise reduction as I wanted.

Switching NIK Dfine back into RGB Viewing Mode (in the upper left) allowed my to verify that my adjustments did not degrade the color within the stars.

This is the finished result using NIK Dfine with 6 custom Color Range controls set for the sky exposure. Discovering that Dfine has the ability to designate Color Range controls at will has allowed me to use it quite effectively to reduce high ISO noise in pinpoint star images.

Stacking multiple exposures is my first choice to reduce noise in high ISO pinpoint star images, but when that is not possible, I will be turning to NIK Dfine frequently in the future. My next step will be to explore using Dfine with custom Color Range controls applied through a luminosity mask created with either TKv5 or Lumenzia. If the stars are protected by a good mask, I think I can be a little more aggressive with noise reduction in Dfine without sacrificing detail in the stars.

So what did I learn from conducting this exercise? First, some experiments are successes, while other fail miserably. This one was a failure. Second, good things can come out of failed experiments. It was only when my experiment failed that I discovered the advanced features NIK Dfine had tucked away behind a user-friendly, simplified interface.

Creating Elliptical Star Paths in Adobe Lightroom – Part 2

In the post Creating Elliptical Star Paths in Adobe Lightroom – Part 1, I demonstrated a technique for creating elliptical star paths using Lens Profiles in Lightroom. Here is a similar way to accomplish the same outcome using the Transform Panel in Lightroom.

This technique uses perspective transformation controls within Lightroom to warp a circular shape into an ellipse. The Transform Panel in Lightroom is an equal opportunity transformer, in that it transforms, or distorts, every element contained within an image. Knowing this, we can set up a shot where the the effects of the distortion work to our advantage.

This old abandoned farmhouse in Boxley Valley, Arkansas was a perfect candidate for the use of this technique. To photograph this structure I would usually shoot with at least a 35mm lens, to put enough distance between the camera and the house to minimize the effects of distortion. I would also try to shoot with the camera nearly level and on a high tripod, again, to help minimize distortion. If I were really exacting, I might try a tilt-shift lens to deal with the distortion. But for this technique to work effectively, I actually want to create a controlled amount of distortion on the house. Let’s take a moment to see exactly what I am trying to achieve here.

This diagram depicts a distorted figure of a house in several locations within the frame, along with circles in the upper part of the frame.

Now look at what happens when we go to the Transform Panel in Lightroom and adjust the Vertical Slider until the center house is nearly distortion free. The circles have now been transformed into ellipses. Notice, however, that the other house figures at the bottom also get distorted, along with the circles at the top.

And if we were to go to the Transform Panel in Lightroom and adjust the Vertical Slider and Horizontal Sliders we will see distortion effects applied in a slightly different manner. Here, the house in the lower right appears near normal, while the other elements get warped.

Similarly, if we go into the Lens Corrections Panel and try out different fisheye lens correction profiles we see that there are altogether different distortion correction patterns applied to the image, based on which lens profile is chosen. This is the method that was presented and used in the post Creating Elliptical Star Paths in Adobe Lightroom – Part 1.

By setting up the shot initially with induced subject distortion, and then using various combinations of the sliders in the Transform Panel or Lens Profiles in the Lens Correction Panel, we can create interesting elliptical star paths from within Lightroom while ending up with a reasonably undistorted subject. Some combinations work with some images and not others, but with practice, you will soon get a feel for what subjects work within the constraints of this technique.

Here is a high ISO test shot I took to set up the composition, gauge exposure and verify focus. I chose a 20mm lens, in order to get in close to the house, and set the camera low to the ground. Both of these choices created just the right amount of distortion in the house that I was looking for, knowing that correcting this distortion in post-processing would then morph my star circles into star ellipses.

I shot five 15min@ISO100 exposures, stacked them in Photoshop to create the star circles, then returned to Lightroom (see note below). After experimenting with various settings in the Lightroom Transform Panel, I settled on -40 for the Vertical Slider, which seemed to yield the best results with this particular image. Notice that whenever using the Transform Panel, the resulting image will usually need cropping. I have found that it is good practice to overshoot the intended composition, in order to allow some breathing room for the inevitable crop. The cropping can automatically occur right within the Transform Panel if you check the Constrain Crop checkbox. If you then want to further adjust the crop to you liking, simply unlock the Padlock Icon in the Crop & Straighten dialog, as show above.

With a little additional touch up work to get rid of some color cast, the image was finished to my satisfaction. It turns out this is an interesting, simple and fun technique to add just a subtle difference to the usual star circle images one usually encounters.

Note regarding single vs. multiple exposures for creating star circles

This technique can also be applied without the necessity to stack multiple exposures in Photoshop by merely taking one exposure with a duration long enough to create the star trails of the length you desire. I prefer to use multiple exposures for a variety of reasons, but there are two reasons that I find most compelling. Both involve automobile lights, but in opposite ways.

First, there is the serious risk of an unusable exposure due to automobile headlights intruding into the scene. Suppose you are 57 minutes into a 60 minute exposure, and a car drives by and casts its headlights directly into the scene. Most likely you will have to retake the image. On the other hand, if you had decided to capture ten 6 minute exposures and stack them to create an hours worth of star trail length, you could easily mask out the spoiled portion of the relevant exposure, and all would be well. In fact, the more exposures you take, the better your odds of having a successful star circle image.

Second, you never know when incidental automobile headlights will be your friend. I often hear photographers grumble about passing motorists. Not me! Once I learned that it is not extremely difficult to mask out unwanted lights in one of a series of multiple exposures, I was free to embrace automobile headlights as a creative tool. In many instances, automobiles have accidentily provided just the right lighting touch on the subject in a way I could not have created on my own.

Here is an example of a “happy accident” where I was shooting multiple exposures of the Milky Way in order to stack for noise reduction purposes. A passing motorist supplied the perfect lighting for the rubble ruins in the mid-ground in a way I could not have duplicated, and all quite by accident.


Moonrise Over Bodie – ISO Invariance In Actual Use

I have been experimenting with various ways that I might benefit from the ISO invariant nature of the Sony A7Rii camera. For those unfamiliar with the concept, ISO invariance is discussed in the DPReview article Sony A7Rii: Real World ISO Invariance Study published in August of 2015, where they did some daytime testing of ISO invariance (the comments are arcane and technical, but contain valuable information).

Important Update

Since writing this post, two important and informative articles have been published that are must reads for anyone interested in the topic of ISO invariance.

The first article, by Ian Norman of Lonely Speck, is entitled How to Find the Best ISO for Astrophotography: Dynamic Range and Noise

The second article is by Spencer Cox, and is entitled ISO Invariance Explained

Both articles, while highly technical (especially the second), do a thorough job of explaining the nuances of ISO invariance, and are well worth the time required to digest their contents.

The concept of ISO invariance arises from two different camera architectures in common use to record RAW files today. The image sensor is an analog device. Its pixel output is measured in voltage levels.  In a traditional architecture, the electrical signal will pass through electronics that control the gain, or amplification of the signal depending on the ISO set in camera. This gain, both the signal and the noise, will be applied uniformly across all pixels, which then get sent to an ADC (analog to digital converter) and from there are baked into the RAW file.

The ISO invariant camera architecture differs in one respect. The analog pixel signals travel directly from the sensor to the ADC, and any “gain” applied via the ISO setting is actually accomplished in the camera software. At that point it is then baked into the RAW file.

The theory is that since the ISO setting is applied in software, why not postpone the software boost until post-processing, rather than in camera. That way one can selectively boost exposure only in those areas that need the boost, and leave the rest of the image alone.

Luminous Landscape wrote a brief post regarding ISO invariance, and the post ISO INVARIANCE: WHAT IT IS, AND WHICH CAMERAS ARE ISO-LESS appeared on the Improve Photography website, but neither provided any examples of ISO invariance in real-world use. The biggest critique I could find of using ISO invariance techniques appears to revolve around the idea that ISO invariance fails the test in Sony cameras because of the RAW lossy compression scheme originally implemented by Sony. Whether that is an issue or not is now moot, as Sony has updated firmware to allow uncompressed RAW files as an option. If that had been a problem in the past, it is now gone.

Over the past year, as opportunities presented themselves, I played around with the ideas behind ISO-less shooting in my night photography, with some successes and some failures. The photograph Moonrise Over Bodie at the top of this post is one of the successes, and shares a common trait with the other successful exposures I made with this technique – very high dynamic range, combined with sufficient ambiant light to allow the sensor to record useful information in the deep shadow areas. In other words, my moonrise and moonset shots. Beyond that, I am continuing to explore other situations where this might be a benefit, but for now, it is the tool I turn to for images such as the Moonrise Over Bodie. Here is a description of how I captured and processed this image from one single exposure and approximately 10 minutes in Lightroom.

So here is “backstory” number one. In July 2016 I participated in a Full Moon Night Photography Workshop presented by Lance Keimig in Bodie, California, While the focus of the workshop was light painting and night photography under full moon conditions, we were presented with a brief period during the last night where the Milky Way would be visible immediately prior to moonrise, which is when I took the shot above. As the moon began to rise, rather than head back into the ghost town, I decided to stay atop the knoll I was perched on and do some experiments involving the moon.

Here is my first exposure, taken at ISO 6400 for 13 seconds.The sensor was gathering sufficient data in the foreground region, but clearly the highlights were blown out in the sky with the full moon now above the horizon. While I expected the sky to be blown out, I was pleased to see that ISO 6400 allowed plenty of detail to be recorded in the foreground. But how to tame the moon?

In my usual workflow, I would take a series of bracketed exposures and either blend them manually in Photoshop or process them as an HDR image. Both methods can be difficult, time consuming, and prone to unnatural looking end results. I wanted to find out if there was a quick, easy way to capture the photograph I had envisioned in my head, and all with a single exposure.

This is where “backstory” number two comes in. While participating in a workshop conducted by Mike Berenson and Darren White in the Grand Tetons, Mike taught the group an in-camera dodge/burn method he calls the “Magic Cloth” technique. The photo above gives the general idea behind the technique – use a black cloth (or card) to cover a portion of the lens for part of the exposure, thereby simulating the use of a graduated neutral density filter.

After several attempts with the magic cloth I captured this RAW file, which is the best of all my attempts, but probably nowhere as good as I could have achieved if I were to have devoted more time to the process. But time was growing short, and our group’s chaperon was there to ensure we all vacated Bodie by a designated time.

The best result I could get from the magic cloth technique is shown above. Clearly, my implementation of this technique failed. This is the result of pulling up the sky by just +3EV.  Not what I was hoping for, so on to the next test.

This is an exposure I took specifically for use with the ISO invariance of the Sony A7Rii in mind. It is a thirteen second exposure @ ISO 100. If the ISO invariance theories hold up, then I should be able to selectively boost the shadow areas by +6 EV and see noise results similar (and no worse) than if I had shot in-camera at ISO 6400. Well, there’s only one way to find out – by trying!

OOOPS!! Lightroom limits the exposure adjustment to +/-5 EV, but I needed to boost exposure +6 EV to make a comparison. There is a workaround, and one that actually forces us into a mode that benefits what I am trying to accomplish with this image. The trick is to create a virtual copy of the image file in Lightroom, then with the original and virtual copy selected, Merge to HDR. Leave the ghosting and toning options unchecked, and the resulting file that is returned is a file that has been converted internally from 16-bit to 32-bit floating point mode. Nothing else has changed in the file.

Notice that Lightroom now allows up to a +/-10 EV adjustment to the 32-bit image, which gives Lightroom some additional mathematical breathing room to do its bit-banging magic.

Now that Lightroom is using a 32-bit format, I can readily boost selected areas to my heart’s content, limited only by the noise that is produced by such actions. Notice that the sky has been tamed, there are pinpoint stars appearing along with the full moon, and the foreground is properly exposed. All from a quick, single exposure in the field and just a few moments in Lightroom. No composites, no blending, no bracketed exposures or HDR processing.

The noise that the RAW files exhibit can be compared in the screen capture above, both of which are 300% crops of the images. On the left is the image shot at ISO 100, merged to HDR to produce a 32-bit file, and boosted +6 EV in Lightroom.  On the right is a RAW file taken at ISO 6400 in camera with 0 EV boost. As far as my eye can tell, the results are identical, or so close as to be negligible. It seems that there just might be something to this ISO invariance concept, after all. I will be testing the concept for other scenarios in the future, but for now, I intend to ALWAYS take a low ISO exposure when I am out shooting high dynamic range images at night, if only because they may become the best RAW files to use for a particular shot, once back at the editing workstation.