Forum Login

Introduction to Landscape Astrophotography

by Adam Woodworth

Hopewell Rocks
Nikon D800E, Nikon 14-24mm f/2.8 lens @ 14mm/2.8.
Two exposures blended for depth of field and lower noise in the foreground.
Sky exposure: ISO 3200, 25 sec.
Foreground: ISO 3200, 10 minutes.

My video tutorial on landscape astrophotography editing is now available!

Welcome to the night sky!  In this tutorial I will describe many of the tools and methods I use to create fine art landscape astrophotographs.  I will be focusing on capturing photos of the Milky Way with minimal star movement.  This tutorial does not cover star trail photography.  My goal as a landscape astrophotographer is to create high quality dramatic images of the night sky, and as such I will be focusing on using professional grade tools with a strong attention to detail, with the end goal of being able to create large fine art prints, not just small photos for online viewing.

Keep in mind that my method isn't the only method, and you should experiment and figure out what type of images you want to create and which tools and methods work for you.

I should point out that this article assumes that you already have a fair amount of photography knowledge.  If you're jumping straight into night photography as your first photographic endeavor then you should familiarize yourself with camera exposure settings, lenses, etc.  Photography is a technical field, and fully grasping the details is essential.

So let's get started by talking about camera gear!

Milky Way Waterfall
Sky exposure: ISO 3200, 25 sec.
Foreground: 3 separate exposures, most of the foreground is from a single 20 minute exposure at ISO 1600 and f/2.8. Two other exposures were used to help with depth of field and blending with the sky, ISO 1000 for 5 minutes @ f/2.8, and ISO 1000 @ f/8 for 60 seconds with light painting on the rocks in the closest part of the foreground.
I didn't like the way light painting was causing shadows on the farther rocks, so I ended up doing the 20 minute exposure to get a less harsh look.  I used chemical handwarmers inside a sock taped to the lens to keep it from fogging up during the long exposure.

 

Equipment Needed

Full Frame DSLR

You can try to get by with a crop sensor DSLR, but you really want a recent full frame DSLR.  Full frame will give you much less noise and greater dynamic range.  Night photography pushes image sensors to their limits, and recent full frame sensors are better at handling noise and dynamic range than ever before.

Within the full frame size you can chose a high pixel density or low pixel density sensor.  Low density means fewer but larger pixels (technically these are photosites on a sensor), and high density means more but smaller photosites.  The trade off is that sensors with larger photosites will gather more light and thus have a greater signal-to-noise ratio but with a lower resolution, while sensors with smaller photosites will be more noisy but with a higher resolution.

That said, I use a Nikon D800E, which has a high pixel density of 36 MP.  The Nikon D4, at 16MP, would be less noisy but it is also twice the price.  I also find that the extra resolution helps for making very detailed images.  Stay away from older full frame cameras.  The Canon 5D Mark II is a very popular landscape camera but it doesn't do well at high ISOs.  Go with the much newer 5D Mark III or one of the other recent full frame Canons if you're a Canon shooter.  As of this writing I've heard that the Canon 6D is excellent in low light.  I'm unfamiliar with the full frame offerings from Sony, but Sony does make the sensors that go into some Nikon cameras, such as the D800/D800E, so their cameras might perform well at high ISO.

Keep in mind that new models come out all the time, so always check out the current full frame offerings to see how they do in low light.

Fast & Wide Lens

This is probably the single most important piece of equipment.  The lens is your camera's view of the world, and cheaping out here will mean you're not using the full potential of your camera.  You'll want a very fast (large aperture) wide angle lens.  Arguably the best lens around for super wide angle night photography is the Nikon 14-24mm f/2.8 lens.  This lens is often used on Canon full frame DSLRs by way of an adapter.  Both Canon and Nikon make 14mm f/2.8 prime lenses, but the Nikon 14-24mm f/2.8 is sort of the gold standard of fast ultra wide angle glass.  The Rokinon 14mm f/2.8 lens is a popular fast wide angle lens that is very affordable, but the quality varies from copy to copy and it definitely does not replace a pro grade lens.  Overall, you want a lens that is sharp at its largest aperture (smallest f-stop), otherwise the stars will be soft and blurry.

Of course you don't have to stick with ultra wide lenses, and both Nikon and Canon make a 24mm f/1.4 lens that would allow for lower ISO exposures.  Although maybe not as low as you'd hope for sky exposures given that you'll have to expose for a shorter amount of time to minimize star movement at 24mm compared to 14mm.

I use a Nikon 14-24mm f/2.8 for most of my night photography.

Sturdy Tripod & Head

You need a tripod for night photography, and since the exposures can sometimes be many minutes long, you want a very sturdy one that will easily support the weight of your camera and lens for long periods of time.  Some tripods have a center column that raises up for more height.  Do not use this, it turns your sturdy tripod into an unstable monopod.  Some tripods let you remove it entirely to save weight.

You'll definitely want a tripod head that uses a quick release clamp that supports using an L-bracket.  The L-bracket attaches to your camera and will allow you to quickly orient the camera vertically without having to flop the tripod head to the side, allowing for better stability and overall easier operation.

I use a Gitzo GT2542L tripod (center column removed) with an Acratech GP ballhead.  There are more heavy duty tripods and heads available at the cost of greater weight.  I've been very happy with my setup and I've even done long exposures in the wind, although a head that lets you control each axis of movement separately might be even better, at the cost of it being bigger and heavier.  The benefit would be the ability to make small adjustments to composition for a single axis without effecting the rest of the orientation of the head.

Remote Timer & Release

For some reason camera manufacturers have designed limited firmware for the cameras that (usually) only let you chose 30 seconds as a maximum exposure time.  Sometimes you need to expose for longer than that, particularly when doing long exposures for the foreground.  Thus you will need a remote timer for your camera.  This can be a wireless or wired remote.  It will accomplish two things: it will let you trigger the shutter without actually touching the camera (reducing camera shake), and it will let you control the length of the exposure from anywhere between 1 second and many many minutes.  You should get one that will also let you set it up to automatically take multiple photos, which you can use for star trail photography (not covered in this tutorial).

I really haven't found a perfect solution for a remote timer.  The Vello ShutterBoss is what I normally use but I've broken a few of them due to a weakness in the design where the cable attaches to the body of the remote.  I have a wireless ShutterBoss as well but the buttons are little too sensitive and you can very easily hit one button by accident that would prematurely end your long exposure, so don't put it in your pocket.  I suggest carrying a couple remote timers with you in case one breaks.

I haven't used one (yet) but the Promote Control looks like it could be a great solution, it doesn't look like it has the cable design weakness of the wired ShutterBoss.


West Quoddy Head Lighthouse
Dew in the air kept fogging up my lens, and I didn't have a heater to keep the lens warm so I was only able to take a single exposure for this photo. As a result the bottom of the lighthouse is a little out of focus.
Nikon D800E, Nikon 14-24mm f/2.8 lens @ 14mm/2.8, ISO 3200, 25 seconds.

 

Shoot RAW

If you're not shooting in RAW format with your camera then you need to start doing that and learn how to process RAW files.  The RAW format is a digital representation of what the camera captured without any parts of it "lost" due to compression.  Although some cameras support compressed RAW, so make sure you're not using that.

Software Needed

You'll need a very good raw editor to go along with your RAW files.  Night photography requires the use of high ISO exposures, so you want a RAW editor that can make the most of the limited dynamic range of such high ISO exposures.  I strongly suggest using Adobe Lightroom.  Adobe Camera Raw, which comes with Photoshop, contains the same RAW editor as Lightroom, but Lightroom will make organizing your photos a lot simpler.

Photoshop

Photoshop is used to blend exposures together and for editing the final image in ways that are not possible in Lightroom.  There are some plug-ins for Lightroom that allow you to blend photos together, but you'll have the greatest control over your entire image editing process if you have Photoshop.

Noise Reduction

You may need a plug-in for Photoshop or Lightroom to help with noise reduction, particularly for the high ISO exposures of the sky.  I use Nik Dfine as a Photoshop plug-in and find that it does an amazing job, better than what Lightroom and Photoshop provide by themselves.

Finding the Milky Way

When photographers talk about the Milky Way we usually mean the galactic center, which is the densest and widest part of the Milky Way, and thus the brightest part to our eyes and to the camera.  Whether you can see the galactic center depends on your location and the time of year.  The brightest part of the Milky Way is near the constellation Sagittarius and stretches up towards Cygnus.  Various software applications are available to help you determine if you can see the Milky Way at night from your location.  On the iPhone/iPad I use Star Walk, which is a commercial app, but Planets is another app available for free with a limited interface.  I'm not familiar with Android apps, but it looks like Star Chart would fit the bill.  You can Google for other options for iOS, Android, or desktops.

Finding the Milky Way using Star Walk for the iPhone.

 

Find a Dark Sky

A very dark sky is necessary in order to see the greatest detail in the Milky Way, so you want to be far away from the light pollution of cities and out at a time when the moon isn't going to wash out the sky.  On the other hand, you can sometimes use light pollution to dramatic effect, and when the moon is low enough in the sky you can use it to light up the foreground.  There are various apps available that will show you the phase of the moon and when it will rise and set.  I most often use Focalware on the iPhone for this but there are many apps, including lots of free ones, that can do this.

You can head on over to the NASA imagery of city lights at night, which can help you find dark sky areas.

Focus Bracketing

Due to the physical limitations of current cameras (not including something NASA might be able to produce), it is physically impossible to take a single exposure where both the stars and foreground are in focus while having minimal movement in the stars, a detailed sky, and a non-noisy foreground.  In order to get an exposure for the stars at 14mm on full frame you need to expose somewhere around 20 or 30 seconds at f/2.8 or better, which means that if you're composing a shot with a near foreground it won't be in focus, and at such high ISOs required for the sky the foreground would also be very noisy.  So in order to create an image with a well exposed and in focus sky and foreground you can take multiple exposures at different focus distances and ISOs and then blend them together in Photoshop to create the final result.  This is an advanced topic and I won't cover the details of it all here, but stay tuned for future tutorials.

Update: I now have a crash course video on exposure blending available here.

Update 2: You can now purchase my 2+ hour video tutorial series titled "Landscape Astrophotography Editing Workflow" here.

 

 

Light Painting

Light painting is a way of lighting your foreground at night by using a flashlight or some other source of light.  This technique takes some practice to perfect.  You'll probably want to use a diffuse light source because focused bright light can create very harsh shadows.  I don't light paint too often, but when I do I often use a lens cloth over a flashlight, or bounce the flashlight off of something behind me, in order to cast soft light on the foreground.

The biggest thing you want to avoid is what I call the "car headlight" problem.  This is when lightpainting looks like a car was parked behind your camera, shining its headlights onto the foreground, meaning that the foreground is far too bright compared to the sky and has harsh transitions between light and dark areas that look obviously like a light had been shining on the foreground.

Sometimes light painting is the only way to get a good exposure of the foreground within a reasonable amount of time if the ambient light is so low that it would take too long to capture a good exposure of the foreground.  "Too long" is subjective, but one example would be when you're at the ocean and the tide is coming in and would cover you and your camera if you didn't move.

Lupines at Night
Light painting and focus bracketing were used to get the foreground field of lupines well exposed and in focus.
Nikon D800E, Nikon 14-24mm f/2.8 lens @ 14mm/f2.8.
Sky exposure: ISO 2500, 25 sec.
Foreground: 5 separate exposures, different focus distances, each at ISO 1000 for 60 seconds.  The foreground exposures were light painted with a diffuse light - an incandescent flashlight with a lens cloth covering the bulb.

 

Camera Settings

So here we are, at the section that I get the most questions about.  I'm frequently asked what settings were used for an image, but it is critically important to understand that the camera settings are only part of what makes an image, and the rest of it is what you do for editing in software.  Using the exact same settings I use will not give you the same results out of your camera because there is a lot of editing needed after the shot is done.  The photos that come out of the camera are the starting point, the rest is crafting the image in the "digital darkroom".

First off, you need to enable exposure delay or mirror lock-up in your camera.  These settings create a delay between when the mirror is flipped up and when the shutter is opened.  That delay lets the vibrations from the "mirror slap" dissipate before the exposure starts.  I use a 3 second exposure delay.

Also, make sure you're shooting in RAW mode.

For white balance I normally leave this on auto and fix it later in software.  With RAW files the white balance is just a piece of metadata and doesn't actually effect the data in the RAW file.  You can completely correct the white balance of RAW files in your RAW editor.

Minimizing Star Trails

You may be surprised to discover how quickly the stars appear to "move" across the sky in your photos due to the Earth's rotation.  This shows up in photos as star trails, instead of looking like pinpoints the stars look like streaks in the sky.  In order to minimize star trails you have to limit your exposure to where the trails are acceptably small enough to look like pinpoint stars.

You may have heard of something called the "500 Rule".  The idea being that you can calculate the exposure time for minimal star trails by dividing the 35mm full frame focal length into the number 500.  Thus, for a 14mm shot, you'd come up with a "500 Rule" value of 36 seconds (500/14 = 35.7).  However, I find 36 seconds at 14mm to be too long of an exposure, the star trails are too big.  Doing the math, it looks like I tend to follow a "400 Rule" (I'm often using 25 or 30 seconds at 14mm), but you'll just need to experiment and find out what works for you.  Keep in mind that when using ultra wide lenses the lens distortion will cause the stars in the edges of the frame to have longer trails than those in the center of the frame.

If you're using a crop camera you'll need to use the 35mm equivalent of your lens' focal length.  This is calculated by multiplying the focal length of your lens by the magnification factor of the camera.  Nikon DX cameras are 1.5x, Canon crop cameras are 1.6x.  E.g., for a 10mm crop lens on a Nikon DX camera, you'd multiply 10 * 1.5 to get a 15mm full frame equivalent, then you would divide that value into 400 (or 500).

Long Exposure Noise Reduction

High ISO long exposures often result in hot pixels, pixels in the exposure that are clipped to bright red, green, blue, or white.  In order to limit the amount of these hot pixels you can use your camera's Long Exposure Noise Reduction (LENR) setting, if your camera has it.  With this setting turned on, for each exposure that you take that is over a certain length (on my D800E it kicks in for any exposure over 1 second) the camera will take another exposure at the same settings but with the shutter closed.  This is called a "black frame", and the goal is that the exposure will contain most of the same hot pixels as the actual exposure, and the camera can then "fix" those hot pixels in the actual exposure before writing out the final RAW file.  This does mean that your exposures will take twice as long but in my opinion it is well worth it.  If you don't do this you'll likely end up having to spend quite a bit of time cleaning up hot pixels manually in your RAW editor or Photoshop.

Focusing In The Dark

As you may have experienced before, focusing in the dark is rather tricky. And if you're focus stacking you will need to change focus multiple times. So how do you do this in the dark? Ultimately the answer is that you will need to practice with your lens and examine the results. Not all lenses focus at infinity when the focus ring is set to the infinity mark. Many lenses will change their infinity point as the ambient temperature and humidity changes, and on zoom lenses the infinity mark may only be accurate for part of the zoom range.

On my Nikon 14-24mm/f2.8 lens I know that when it is at infinity then the stars are in sharp focus, even at f/2.8. This has been true of my lens in various temperatures, whether it's well below freezing or in the heat of summer. I know some other photographers with the same lens that have had the same experience, and others who have not, so it will depend on your luck of the draw with what you get from the factory, but you may be able to send your lens in for repair to correct it.

If you cannot get your lens to capture sharp stars at your widest aperture setting regardless of your focus distance then you may have a lens that is just not sharp with pinpoint light sources, or the lens may need repair.

For foreground exposures you can sometimes use a flashlight and live view to help you focus. On the other hand I often rotate the focus ring to varying points on the lens for each foreground exposure because I know my lens well enough to know where I should rotate it to and how many shots I may need for the depth of field of a given scene, but it always comes down to checking my results in the LCD.

Expose!

The actual exposure settings will depend on your camera and what you're photographing.  My night photos almost always consist of multiple exposures, one for the sky, and additional ones for the foreground at different focus distances at lower ISO for longer exposure durations.  The additional exposures for the foreground allow me to capture the foreground with much greater detail and sharpness than using just one exposure for the sky and the foreground.  All of these exposures are then blended in Photoshop to create a single image.

For my sky exposures I'm usually shooting at ISO 2000 or 3200, 25 or 30 seconds, 14mm (full frame), at f/2.8.

You'll need to find out what works for your camera.  If your lens is slower than f/2.8 you may have to sacrifice some noise and/or star trails by exposing at a higher ISO and/or longer time.  Or if you're zoomed in more you may need to use a shorter exposure time to limit star trails and possibly a higher ISO to capture more light over the shorter exposure.

For the foreground exposures you'll want to stay at the same focal length (I'm normally at 14mm on full frame) but the ISO, exposure time, and f-stop can all vary.  Depending on the amount of ambient light in the area, or if I'm light painting, I may be using anywhere between ISO 400 to 1600 or even 3200, for anywhere from 60 seconds to 10 minutes.  It really depends on the situation and you'll need to experiment and be knowledgeable of "exposure math" to find out what works for your camera in various situations.  I often take multiple foreground exposures at differing focus distances, sometimes as many as 8 or 9 exposures, but you can also take a single foreground exposure at a small aperture (high f-stop number) for a very long exposure duration to get a single shot that has the entire foreground in focus.  Then you blend the foreground exposures with the sky exposure in Photoshop to create a single image.

New Hampshire Seacoast
This image consists of two exposures blended together.
 The bright area above the left side of the horizon is from the sun nearing the horizon for sunrise (but still well before sunrise).
Nikon D800E, Nikon 14-24mm f/2.8 lens @ 14mm/2.8.
Sky exposure: ISO 3200, 20 sec.
Foreground: ISO 1600, 120 seconds.

Editing Basics

Taking the photos are only half the process of photography.  The editing process is where you clean up the photos, blend them together (if you're doing focus stacking), and craft your final image.  If you rush through this part and don't develop a personal style your photos will reflect that rushing and will not look professional.  I will not be getting into the fine details of editing in this blog post, but I will cover some basics to get you started.

Basic Workflow

If you're going to be blending multiple exposures (focus stacking) in Photoshop you should make basic edits in Lightroom (or Camera Raw) first.  At a minimum you should correct white balance, adjust sharpening (see below for how to not sharpen the noise), remove chromatic aberration and any other lens corrections.  You may want to check "Enable Profile Corrections" to fix distortion and vignetting, but I often only fix vignetting.  You may want to add vignetting back to the photo later as a creative effect, but getting rid of the lens vignetting first will allow you the greatest room for editing.

After making the basic edits, you can then export the exposures into Photoshop and blend them together to create your single image.  Once blended, you can then continue editing in Photoshop, or edit the blended photo in Lightroom (and again in Photoshop if you want!) to craft your final image.

White Balance

Chances are you'll need to adjust the white balance of your photos.  I usually put my camera in auto white balance mode and then correct it all in post.  But even if you did chose a particular setting you'll likely want to change the white balance anyways.  You can use the white balance to make the colors look more natural, but you can also use it for creative effect to shift the mood of the photo.  Remember, when you shoot RAW you can completely correct the white balance in software, you don't have to worry about the adjustment causing artifacts in your photos.

Sharpening

Sharpening is one of the most important steps in digital photography that is often overlooked.  For night photography you can use it to sharpen up the stars a little bit and sharpen the foreground details, but the most important thing is make sure you're not sharpening the noise in the photo.

By default, Lightroom (or Camera Raw) will sharpen the entire image.  You will want to adjust the Masking slider in the Sharpening section of the Detail panel so that blank parts of the sky are not being sharpened.  If you don't do this, then the noise in the sky will be sharpened, which will make it more prominent.  Hold down the option key (Mac) or alt key (Windows) while dragging the Masking slider to see a mask overlay on your image showing where the sharpening will be applied.  The white parts of the overlay are the areas that will be sharpened.  So you want the blank parts of the sky to be black so that the noise in the sky isn't being sharpened.  You can also do this while zoomed into your image to see the full detail of the mask, which will let you fine tune it.

Hold down opt (Mac) or alt (Windows) when dragging the Masking slider in Lightroom to see where the sharpening will be applied.  White areas will be sharpened.

Clarity

The clarity slider in Lightroom (or Camera Raw) is one of my favorite tools.  When used on the sky exposure, positive clarity will really make the stars pop.  But be careful when using it, you can easily add too much clarity and cause ugly halo artifacts, particularly around the horizon.  If this happens you can just back off on the clarity, or you can only brush in clarity where you want it with a local adjustment brush or gradient.  Or use global clarity and brush the clarity away from where you don't want it using negative clarity.

Noise Reduction

With such high ISOs needed to capture the night sky without star tails you'll probably find that your images need some noise reduction.  Your RAW editor should provide some noise reduction, but you'll probably get much better noise reduction by using a third party tool, often as a plug-in for Lightroom or Photoshop.  I personally use a little bit of noise reduction in Lightroom before exporting the photos to Photoshop, where I can then apply much better noise reduction using Nik Dfine.  You will want to practice and find the right balance between smoothing out noise in the sky without smoothing out the stars.

Jackson Falls
Nikon D800E, Nikon 14-24mm f/2.8 lens @ 14/2.8.
Sky exposure: ISO 3200, 30 sec. Foreground: ISO 1000, 5 minutes.

 

Go Shoot!

Now that you've learned all the basics to landscape astrophotograhy it's time to find a dark sky and practice! Good luck and have a blast!

About Adam Woodworth

Adam Woodworth is a landscape photographer, fine art printer, award winning filmmaker, and software engineer.  He is originally from Maine and now resides in New Hampshire.

His goal as a photographer is to create compelling images using high quality tools and techniques.  His attention to detail as a long time computer programmer is not lost in his photography and fine art printing.

You can see more of Adam’s work at www.adamwoodworth.com and follow him on his blogFacebook, or Google+.

Many thanks to Luke Barton for hitting the shutter button on my camera for my profile photo!

November, 2013


Filed Under:  
Essays    Tutorials   

show page metadata

Concepts: Photography, Raw image format, Digital single-lens reflex camera, Aperture, Digital camera, Exposure, F-number, Adobe Photoshop

Entities: Nikon, Photoshop, Canon, etc.  Photography, Sony, Adobe, Google, Lightroom, Facebook, Cygnus., Google+, Milky Way, white balance, focus ring, focal length, ambient light, depth of field, digital photography, computer programmer, auto white balance, software applications, chromatic aberration, alt key, option key, editor, software engineer., Android, Windows, NASA, Adam Woodworth, Nik Dfine, Adam Woodworth, Luke Barton, Mark III, His, D800E, D800/D800E, New Hampshire, Maine, Lightroom, Photoshop, iPhone, iOS

Tags: exposure, camera, lens, night photography, Milky Way, noise reduction, exposures, white balance, foreground, long exposure, raw editor, light painting, different focus distances, foreground exposures, sky, star trails, camera exposure settings, single foreground exposure, high ISO exposures, Nikon 14-24mm f/2.8, multiple foreground exposures, sky exposure, Camera Raw, multiple exposures, exposure time, actual exposure, frame, single exposure, fine art, sky exposures, maximum exposure time., hot pixels, wide angle lens, long exposure duration, Nikon D800E, ultra wide lenses, high pixel density, shorter exposure time, separate exposures, Adobe Camera Raw