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Tuesday, March 5, 2024

Tips for taking Nightscapes from a drone

A DJI Mavic 3 drone photo, taken above the Outeniqua Pass foothills in South Africa by Agnieszka Taggart

 Written by Agnieszka Taggart

Agnies is a licensed drone pilot and instructor in Johannesburg, South Africa.

Drones are becoming more popular among photographers so it’s no surprise that with the improving specifications, they are also becoming usable in night sky photography.

There are couple things to consider though.

One is the legal side of flying drones at night as some countries only allow drones during the day or with special permissions.

The second one is drone capability to take long exposure photos. Modern drones are quite good at holding the position, but what’s considered good in the world of drones, may not always be good enough in terms of optics and photography.

Typically, the longest exposure from a drone is 8 seconds, but it does not mean that all your exposures taken at 8s will be usable - this is to the fact that even within this rime, the drone will have some movement, usually caused by wind.

Drones typically use the below systems to hold the position:

  • GPS: modern drones use as many satelites as they can detect, 12-15 satelites is needed for good position lock, sometimes even more. Accuracy increases with number of available satellites
  • Compass/ gyroscope: this defines which way the drone is pointing 
  • Visual sensors: many drones are equipped with visual sensors for position hold. The sensors scan the ground and register the image  - the more contrast and illumination, the better the visual position hold. 

In order to get good position lock, hover over something bright and with good contrast - you might want to put a torch on a landing pad.

Accuracy of visual sensors decreases with height, so do not fly high if you don’t have to. In most cases, you only need to clear the height of the roof and trees, so 10-15m above the ground should be enough. Wind is also weaker close to the ground and increases and often changes direction as you mice up.

* Do not take off from a car roof, there is a lot of interference from car electronics that might affect the accuracy of the drone compass. If you chose to hover above a car, take off from a different spot and move over once you reach required height.


Based on the above, you might need to adjust your regular work flow for all types of night time photography.

1) Single exposures

As mentioned, you will be limited to 8 seconds. That’s short, so in order to have usable image, you will need to dial up your ISO. I typically use ISO3200 on my Mavic 3. In case of single exposures, sensor size is the key. You might get away with 1 inch sensor, but 4/3 will produce better results. Take many shots and choose best - they will not all be usable. The types of photos that work well in this situation are naturally contrasty and well illuminating landscapes (snow, sand, water, pale rocks such as sandstone and dolomites), landscape with busy road to capture the trailing lights and non-aggressive light painting

2) Blending and stacking

Typically you would take some shots at “blue hour” and then some night sky shots later. With this technique, it is critical to keep the drone in same position. It is extremely unlikely that you will do this with a single battery, so you will have to record the exact drone position, direction and height. You may want to create a waypoint if your drone app has this function.

3) Composites

Using drone for night time photography is challenging and you may be left with no option than to create composite. If you do, make sure that it is true to nature - check the directions and star positions. It is useful to take a shot with most prominent stars and combine it with shots from the ground. And of course ALWAYS reveal the technique.



Friday, March 1, 2024

Calculating Your Low Level Lighting Exposure

LED Panel lights at Fairyland Point, Bryce Canyon

How to Calculate the Proper Intensity of Your Low Level Lighting

Calculating Your Exposure: Your exposure is actually determined by your sky exposure, which is often something like f/2.8 for 30 seconds at ISO 6400. Since you want your foreground landscape to match that exposure, what you are really trying to do is place an amount of illumination on the foreground that will look natural with your sky exposure. Because it is a night scene, your foreground should be about two stops darker than a daytime foreground.

LED panel lights are one of the most popular Low Level Lighting sources. Because of the “Inverse Square Law” of light, a non-focused light, like a panel light, will significantly lose illuminance (the amount of light reaching the subject) the further it is placed from the landscape foreground. For instance, a typical panel light might give you a 500 lux reading one meter from the light, but place it only two meters and the illuminance drops to only 125 lux, or 1/4 as much (500 divided by the square of 2). Move the light 328 feet away (100 meters) and the luminance drops to 0.05 lux (500 divided the product of 100 times 100). At this distance, you are going to have to rotate the power dimmer switch to about 1/4 power or less to get a proper exposure. A Low Level Lighting of about 0.01 lux illuminance (which is about halfway between 0.008 lux and 0.02 lux) is a good starting point.

Is there an exact method to getting the right exposure for each landscape location? Yes and no. Lux light meters that can take accurate readings in the 0.1 to 0.001 range are scientific instruments that can cost thousands of dollars. Even if you bought and used one in the field, each landscape situation is different and will still require some exposure adjustments to suit your tastes. Using one of the following three methods, I rarely have to make more than one or two light intensity adjustments before I am satisfied with my results:

Lighting Intensity Adjustment Method #1: The Visual Method. Once you have placed your lights at the proper angle and distance away from your landscape foreground, begin to lower the power adjustment switch until you can barely see features against the night sky (remember, you’re trying to mimic weak moonlight, not the light of a full moon). Due to glare from the light, you’ll want to shield your eyes with your other hand, or even better, stand about 30 feet (about 10 meters) to the side of the light and have a partner adjust the light intensity while you call out the adjustments. This visual adjustment is the fastest and easiest method, and you’ll find it to be quite accurate as you gain experience—so accurate that you’ll rarely have to go back and fine tune the intensity more than once or twice. 

Lighting Intensity Adjustment Method #2: The Distance Method. This method requires you to have had some verified experience with the visual method. Once you have had success with the first method, record the power setting and the distance. Keep a record of other distance and power setting combinations. Eventually, you will have power settings for several distances and can interpolate the settings for in between distances. For instance, if your first successful light set up was at 100 paces, and you used the 10% power setting, and your new foreground distance is 200 paces away, you would need four times more light intensity, or 40% power. Undoubtedly, you will still need to make one or two fine tune adjustments.


Lighting Intensity Adjustment Method #3
: Inexpensive Light Meter Method. There are inexpensive lux light meters (about $15-25) that are fairly accurate within to 20 to 2000 lux range. These can be used to measure the light close to light source (within the meter’s range of accuracy) and then interpolated for the distance at the landscape foreground. For example, let’s say your light is 200 paces from the foreground landscape, and you want to obtain a good LLL starting point of about 0.01 lux illuminance at the landscape. To get an accurate meter reading, I suggest you move about 1/50 of your total distance away from the light, which in this case would be four paces (200 divided by 50 is 4). Now, hold your meter in the light path, facing the light and check the meter value. Since the distance from the landscape at your meter reading is 50 times greater than the distance from the meter reading position to the light, the meter reading at four paces needs to be 2500 times greater (50 squared) than at the landscape or 25 lux (2500 x 0.01). In summary, to get that 0.01 lux value at the landscape, adjust your light’s power until your meter reads 25 lux at the four paces position. After making a test exposure, you can make any additional adjustments to your tastes.

Please note that you could have chosen a meter reading position that was only two paces from the light (or 100th of the total distance from the landscape). In this case, the meter reading would need to be 100 lux (100 squared [10,000] times 0.01).




Friday, September 1, 2023

Low Level Landscape Lighting (LLL)

Palouse Falls (eastern Washington state) with and without Low Level Lighting (LLL) • 20 sec, f/2.8, ISO 6400, with a 15mm ultra-wide lens on a full-frame DSLR camera • Copyright Royce Bair • Click image to enlarge


Low Level Landscape Lighting (LLL) public service webpage, provided by Royce Bair and Wayne Pinkston.

What is Low Level Lighting (LLL)?

  • LLL is NOT light painting — which is moving, momentary and difficult to repeat. Light painting is usually a very bright form of artificial lighting, which is jarring to your eyes and others around you.
  • LLL is a form of "stationary lighting" (on a light stand, tripod or lying on the ground).
  • LLL is constantly on during all camera exposures — making it ideal for stacking, panoramas, time-lapse and group settings.
  • LLL has a very low level brightness on the foreground surface that is less than or equal to the light from a Quarter Moon. LLL adds very little light pollution, allowing the stars to be easily seen.


Comparing LLL Intensity with Natural Light

A Comparison of Natural Light Intensity on Earth Coming From the Sun:

The measurement of light falling on the earth from the overhead Sun (90º) is 129,000 Lux. At sunset this drops to 759 Lux. At the start of the Astronomical Dusk (-18.0º), illumination from the sun drops to 0.000645 Lux! This is the darkest period of the night and the best time to photograph the Milky Way stars.

Photo courtesy of PhotoPills


   Sun Position  Intensity      Time of Day                  

  • 90 degrees  129,000 lux    Noonday Sun
  •  0             759         At Sunset
  •  -4             29.9       Start of Blue Hour
  •  -6              3.41      End of Blue Hour 
  •  -12             0.00806   Start Astro Twilight
  •  -18             0.000645  During Astro Dusk

Add to the Astronomical Dusk illumination and you get the following:

  • Total Starlight only 0.0002 lux
  • Total Starlight + airglow 0.002
  • Typical LLL "base" intensity 0.008
  • Quarter Moon phase at 30º 0.00958 
  • Quarter Moon phase at 45º 0.01602
  • Typical LLL "accent" intensity 0.024
  • Quarter Moon phase overhead (90º) 0.0267
  • Full Moon phase at 30º 0.09583
  • Full Moon phase at 45º 0.1602
  • Full Moon phase overhead (90º) 0.267


Click image to enlarge - ©Royce Bair

CONCLUSION: The typical intensity of LLL base lighting is only about 4 times brighter than starlight, and even the intensity of LLL accent lighting is less that Quarter Phase Moonlight!

Here's another example of Low Level Lighting in practice:

Rainbow Bridge (290 feet/88 meters tall, in Utah) photographed with and without Low Level Lighting. The "base" light (an LED panel light dimmed to only 5%) is about 500 feet (154 m.) from the bridge, and producing about 0.008 lux on the surface of the bridge (about 4X greater than the lux from starlight and airglow). Another panel light is behind the bridge, and is dimmed to about 15%. This produces an "accent" illumination under the bridge (about 0.024 lux on the surface), giving more character, shading and dimension. All single exposures were 25 seconds each @ f/2.8, ISO 6400, with a 15mm ultra-wide lens on a full-frame DSLR camera. © Royce Bair. • Click image to enlarge.

How Does Low Level Lighting Compare to Starlight Blends and Twilight Blends?

Low Level Lighting at "Temple of the Moon" ~ Capitol Reef Nat'l Park. © Royce Bair • Click image to enlarge

1. A single exposure (15mm lens on a Canon 6D • f/2.8, 15 sec, ISO 8000)

2. Same EXIF, but with my LLL, and stacked 18 times to reduce noise. I like the drama and "character" one can achieve with LLL — it's similar to moonlight, but you get to control the direction of the light, and it doesn't wash out or lower the contrast of your Milky Way sky.

3. Longer foreground exposure, using overhead starlight (f/4, 120 sec, ISO 6400, with Long Exposure Noise Reduction turned on), then blended with the sky exposure in number one. I like the detail I get in the foreground, but I often do not like the "flat" lighting this technique gives you. One remedy is to do a Blue Hour blend rather than a starlight blend, as these twilight blends have more of from-the-side directional light (see the bottom of this blend page for more details).

4. My LLL exposure (from 2.) blended with the foreground exposure from number 3. This gives me the best on both techniques: more foreground detail (from the longer starlight exposure) AND more "character" from the LLL.

Artificial Light Restrictions in some national parks: As of May 25, 2021 there is no longer any artificial lighting allowed in Capitol Reef National Park due to a new Superintendent’s Compendium.

Capitol Reef now joins Arches, Canyonlands, Zion and Grand Teton National Park (and Natural Bridges Nat'l Mon.) in this artificial light restriction (Bryce has an artificial light restriction, but it only pertains to the viewing of wildlife). Currently, there are only five of the 63 national parks with this restriction, and only one of the 133 national monuments have this restriction. None of the BLM lands have this restriction (that's 245 million acres compared to the 50 million ares of National Parks land). I don't know of any state parks that have an artificial light restriction, but some like the Valley of Fire in Nevada do not allow photography after sunset.


HOW TO SET UP YOUR LOW LEVEL LIGHTING













Tuesday, August 8, 2023

Updated ''Milky Way NightScape'' eBook Version 2.0

 

My NEW, updated eBook premiered March 30, 2024


My original "Milky Way NightScapes" version 1.1 ebook, published in 2015, has been an astro-landscape photography standard reference book, worldwide. The late Alyn Wallace called me the "founding father of landscape astrophotography."

This expanded edition has 198 pages and 725 illustrative images and includes tutorials from 33 "Guest Artists" experts that cover the latest tracking, stacking, blending and panorama techniques, and much more. Some are calling this "the Holy Grail of astrophotography" and the "nightscape photography encyclopedia."

SAMPLE pages. HERE are six (6) sample pages from my new eBook:

Sample pages - Click to view individually

TWO WAYS to GET my NEW eBOOK: You can do a one-time PURCHASE and download for $39.99, or you can become a supporting PATREON for as little as $3/month and get my eBook as one of your benefits of support.












Monday, August 7, 2023

Smartphones for Nightscape Photography

"A photo of Me with the Arch and Starry Sky" by Wu Zhengjie. Taken with a vivo X90 Pro+ ~ Night Category 1st Place winner in the vivo VISION+ Mobile PhotoAwards 2023 (click image to enlarge).

The technology for smartphone cameras is changing rapidly! When I published version 1.1 of my Milky Way NightScapes ebook there were no mobile phone cameras that could decently capture blue hour twilight photographs, let alone photograph the Milky Way stars during the Astronomical Dusk!

Currently, there are are over a dozen smartphone cameras that can do a fairly good job of photographing starry night skies. I will list them below, in order of my preference (based on my research and some of the reviews listed at the bottom of this blog). This list will be updated periodically, so please come back.

MY BEST SMARTPHONE PICKS FOR NIGHTSCAPE PHOTOGRAPHY

  1. Vivo X90 Pro+
  2. Samsung Galaxy S23 Ultra
  3. Google Pixel 7 Pro
  4. Apple iPhone 14 Pro
  5. Samsung Galaxy S23
  6. Google Pixel 6 Pro
  7. Apple iPhone 13 Pro
  8. Samsung Galaxy S22 Ultra
  9. HUAWEI P50 Pro
  10. Samsung Galaxy S21 Ultra
  11. Huawei P40 Pro+
  12. Xiaomi 13 Pro
  13. OnePlus 11
  14. Xiaomi Redmi Note 11 Pro
  15. OnePlus 10 Pro


REVIEWS:

Best camera phone 2023: Smartphones with stargazing capabilities (March 2023)

The 10 Best Phones for Astrophotography (Apr 20, 2023)

5 Best Smartphones For Night Photography! (July 5, 2023)

Night Photography with vivo X90 Pro! - (May 10, 2023) Note: This YouTube video starts at the "Astro Shooting" — you may wish to rewind to the beginning, to see all the features

The Best Smartphones for Astrophotography in 2023 (April 25, 2023)

Friday, August 4, 2023

Setting Up Low Level Landscape Lighting

Low Level Landscape Lighting (LLL) at Fairyland Point, Bryce Canyon Nat'l Park • Lights off in top photo • Two LED panel lights turned on (each at about 5%) in middle photo • Camera moved to left in bottom photo, and pointed up to show more sky. Post processing contrast added to sky (orange light pollution reflecting on clouds from nearby town) • © Royce Bair • Click on image to enlarge

 How I Set Up My Low Level Landscape Lighting (LLL)
for Nightscape Photography

Return to LLL BASICS Home Page



I've been using the F&V Z96 LED Panel Lights for about a decade in my Low Level Lighting. They use five AA batteries, come with magnetic diffusion and warming filters, and have an analog off/on dimmer switch on the back. The Lume Cube LED panel lights are smaller, lighter, have built in Li-on rechargeable batteries, and have digital dimmer switches that show the exact light intensity output (1% to 100%) and the amount of power that is left in the battery. The light color is also digitally controlled from 5600ºK to 3200ºK. You can read my reviews on all three of these lights via the above links.

I use the Lume Cube Panel MINI as the main (base) light source in most of my LLL set ups where the foreground landscape that I'm lighting is less than 300 feet (91 meters) away. Even at this distance, I'm typically using a light intensity of less than 40% power. For distances greater than 300 feet (91 meters), I use the larger Lume Cube RGB Panel Go (which replaced the original Lume Cube Panel).


Omni-directional "camp" lanterns compared

Camp lanterns put out an omni-directional light that are great for use as "accent" lights — putting a warm glow behind a landscape feature, or under an arch. The top photo shows six different digital LED lanterns I have used over the years. Number 1 has the digital likeness and size of a Coleman gas lantern. Number 6 is the one I now use the most. It is the Goal Zero Lighthouse Micro. Its On/Off/Dimmer Button can control whether two LED lights are used (180º light coverage) or four LED lights are used (360º light coverage). It can also control the intensity of those lights. Wrapping semi-translucent cloth (or tissue paper) and colored filters around the lanterns can added additional controls for diffusion and warming the color of the lights.


© Royce Bair • Click image to enlarge

Two filtered camp lanterns were placed under Sunset Arch, in the top photo. A single panel light from the left side provided the dramatic "base" or main illumination. A single filtered camp lantern lighted the underside of Mesa Arch in the bottom photo. The lantern is hanging from a string about 50 feet (15 meters) below the arch (the string is tied to a rock). The intensity of the lantern is easily controlled by raising or lowering the lantern. Two panel lights provided the "base" or main illumination — one on either side of the arch. The panel light on the right side was set at twice the intensity as the panel on the left side, in order to provide shading on the rocks, but with some shadow detail.


LIGHTING TUTORIAL ~ 5 Ways to Produce More Even Lighting

    1. Increase lighting distance
    2. Scrim the foreground
    3. Place the light higher
    4. Feather the light
    5. Use a 2nd light for "fill"

CLICK for a 4-minute video tutorial


LIGHT STANDS

The Impact brand is one of my inexpensive favorites because they are so sturdy and tall (they can rise to a height of 9.5 feet, which makes them great for item #3, above), and they have a wide footprint (52") for greater stability—you'll appreciate that on windy nights. Disadvantages: They are all aluminum, so they are a little heavier than the carbon stands, which are better for backpacking into a location. They are also not as compact (42" when folded), which makes them more suitable for locations close to your vehicle.


The Manfrotto MS0490C Carbon Fiber Nanopole light stand costs about four times as much as the Impact light stands, but your back will appreciate the weight difference, if you have to backpack into your location. Although the stand only goes to 6.5 feet (77.5" / 196.8 cm) height, I can usually make up for that by finding higher ground (and it comes with a leveling leg, so that you can keep your stand vertical on uneven surfaces). For backpacking, you'll like the weight of only 1.65 lb / 0.75 kg and a compact folded length of only 20" / 50.8 cm.


MINI BALL HEADS


Mini Ball Heads are placed between your panel lights and your light stands. The mini ball heads allow you better lighting control (to "4. Feather the light"). The top ball head is a Lube Cube product ($24.99). It's well made, but a little overpriced for your needs, in my opinion. The DSLR shoe mount at the bottom (which also has a female 1/4"-20 thread for tripod or light stand mounting) is not need for our stationary type of lighting. I think the Oben BD-0 Mini Ball Head (via B&H for $12.71) is just as well built, and accepts both 1/4"-20 and 3/8"-16 studs at the bottom, but without the DSLR shoe mount. The bottom mini ball head is a ripoff of the Terra Firma design that you can get from B&H for $15 — or you can get this cheap mini ball head on Amazon for only $3.50! (This product is more than adequate for holding and positioning a light weight LED panel on top of a light stand.) Note: If this product link disappears, just search on Amazon for "Swivel Mini Ball Head 1/4 Screw Tripod Mount" and you should find several similar products.

NOTE: This page is currently under construction. Until it is finished, please refer to this webpage about additional lighting equipment from my friend, Wayne Pinkston.










Saturday, June 24, 2023

Focus Stacking Nightscapes with Marybeth Kiczenski

 

Big Stable Lighthouse by Marybeth Kiczenski • Foreground taken during the blue hour, using several 15 second "focus stacked" exposures at f/8, ISO 800 • Sky is a 90 seconds tracked exposure, ISO 1000, f/2.8 • Sony a7iv  camera, with a Sony 24-70mm lens at 50mm.

Winter blooms at Anza Borrego by Marybeth Kiczenski • Foreground taken during the blue hour, using several 6 second "focus stacked" exposures at f/8, ISO 800 • Sky is five 1-minute tracked exposures (a total data stack of 5 minutes), f/2.8, ISO 800 • Sony a7iv astro modified camera (to visible + H-alpha), with a Sony 12-24mm lens at 14mm.

Step-by-Step Tutorial

A 3-image focus stack taken during the blue hour by Marybeth Kiczenski.

Focus stacking your night images is a great way to improve the overall image quality.  Much of the process is akin to daytime focus stacking – but with a twist.  Depending on if you are blue hour blending, or using true night images, the process may include further post processing.  

One of the most popular case uses for focus stacking involves flowers.  Flowers make beautiful foreground subjects, but with wide-angle images at F/16 – the depth of field rarely is enough for these small, yet mighty, subjects.  

Before we dive in, also note that flowers move.  They move A LOT.  The slightest of breezes can move these delicate subjects.  You may find yourself either giving up, OR doing your focus stack of the flower in blue hour – sometimes VERY early blue hour.  Basically, as soon as the directional light from the sun disappears.  The reason is you’ll need those faster shutter speeds to freeze the blooms.  

Pay attention to the weather considerations and wind.  You don’t want to miss that small window to capture still flowers!  

With that out of the way, let’s get to the task at hand.  You’ll notice here that the flowers here were taken not long after the sunset.  While I had the tripod set up in this spot from sunset to milky way, the sharpest stack was from this early evening time frame.  

Another point to consider:  what is your minimum focus distance of your lens?  As you can see here, the Sigma 14-24mm F/2.8 ART lens failed to catch the focus on the nearest flower to the lens.  But to be fair, it was basically on top of it.  If this is the type of thing that bothers you, then you’ll want to adjust accordingly.  I loved having the flowers frame the scene, so I creatively chose to live with this flaw rather than losing the top anchor flower. 

The yellow dots indicate the approximate focus points the camera chose in each of the three focus stack exposures. The lens aperture was set at f/8. An aperture of f/16 would have given greater depth of focus, but the exposure would have needed to be four times as long, which can cause flower movement, if there is any wind. If focus stacking had been done in total darkness (using an aperture of f/2.8), then a much great number of exposures would be needed to create the focus stack depth of focus (and focus for each would have been done manually).

The actual focus stacking process involves you starting on the nearest subject, and progressively shifting the focus until you reach the infinity point.  You can pick subjects from the scene to focus on, shift your lens step by step, or utilize some camera’s ability to in-camera focus stack.  This image was done with a Nikon D850 – the first camera from Nikon to have this feature built in.  The number of images you’ll need also depends on the aperture you choose. In other words, you’ll need a lot more images to complete the stack  at F/2.8 vs. F/16.  You may have to play around (if your camera doesn’t have the auto feature) to make sure you get everything in focus.  

IMPORTANT NOTE: If you are doing your focus stacking in the dark – you’ll have to manually focus on your different points.  This can be an issue if you are with a group, as the “easy” way to focus on the subject is to shine a light on it, set the focus, then turn it off.  Communication is key!  For this reason, (as well as the aforementioned weather issues), 95% of all my own complex foreground will likely be blue hour foregrounds.  There are times where this just isn’t possible, so you just deal with the parameters dealt!


After you collect all your in-field data (focus stack images and your starry night sky exposure), it’s time to do the process the focus stack:

  1. Open your best sequence in the editing software of your choice.
  2. Apply your basic edits.
  3. Save the edited images.
  4. From here, you can use Adobe Photoshop, or software such as Helicon Focus.  For images that Photoshop has issues with, I will use Helicon.  [Update: recent Photoshop updates drastically improved its built in focus stacking algorithm.]
  5. Open the files as a stack.
  6. Click on “attempt to align layers”
  7. Once the images are loaded into layers, I will then Auto-Align them.  This just insures to me that they are aligned to the best of the computer’s ability to do so.
  8. Select all the aligned layers, then click “Auto-Blend”  The Auto function typically will suffice.

The computer will then apply masking as it sees fit to make a seamless blend.  Photoshop uses depth mapping for this type of stacking.  When that doesn’t work correctly, that’s where Helicon Focus comes into play.  This program features different algorithms to figure out the focus shifting beyond the scope of Photoshop.  You can pick between these algorithms and see how it changes the stack.  

Once you are happy with your focus stacked image, save that file out.  From here we will now go into adding in the sky, and color matching the two assets to make a final composition!


PUTTING IT ALTOGETHER

At this point, you should have two main images to work with:

  1. Focus stacked foreground image
  2. Single exposure / a Stacked exposure / or a Tracked sky image

Open the focus stacked image.  From here you’ll want to apply a mask to remove the sky.  This can be a number of ways.  The easiest of which is using Photoshop’s new “Select Sky” function.  This works remarkably well for well defined horizons.  I find that it starts to struggle with trees.  Sometimes it will remove too much detail in these complex areas.  It’s always worth a try, though!  As it's the easiest method! 

If this fails, you can deploy the very powerful color-channel masking method.  This is a bit advanced, but it's remarkable – especially when dealing with trees.  Here’s the simplified process:

  1. In the layers panel, navigate to the color channels tab.
  2. Click on each channel until you find the one that separates the foreground from the sky the best. Usually this ends up being the blue channel, but not always.
  3. Copy that color channel into its own new layer.  This step is IMPORTANT, as if you don’t copy it, any changes you make will affect the master image.
  4. Use brightness/contrast to create more separation.  You want a black and white image.
  5. Use the dodge and burn tool to define the edges.
  6. Once happy, then select one of the colors – either black or white.
  7. Click back to the full color image – and click on “apply mask”.



Masked Focus-stacked foreground — ready to be blended with starry night sky image


Once the sky is masked out, then you can open your sky image.  Copy that image over to the foreground image into its own layer.  I always put the sky under the foreground.  


Now save this master file out as a new file.  This way you still have an unaltered focus stacked image, in case things go drastically wrong. 

Initial blend of foreground focus-stack and sky exposure

COLOR BLENDING

Here’s where your creativity begins to take flight!  Using the Hue/Saturation, Color Balance, and Selective color under Adjustments, start working the colors until the foreground begins to match the sky, or vice versa.  This is really a personal preference.  Blue hour images – as the name implies – are heavy in the blue/magenta tones.  Some will choose to keep with this theme, and make the night sky match the blue tones.  However, the colors of the natural night sky are not blue.  So you have to make this creative choice.

The magic is really in the color matching for creating convincing compositions.  It can take a lot of small finessing and adjustments, and practice.  

Once you are happy with the color matching, then you can take the editing further with curves, brightness, contrast, using the Nik collection, and more! 

Final post-processed blend