How do you take photos of the night sky like these,
with no special camera equipment? Nothing but an ordinary - even a cheap - camera
on a tripod? It's easy. You just have to know the right technique.
One of the challenges with star photography is this. The stars move across the sky. The
problem is even worse when you zoom in with a telephoto lens,
because you're magnifying that movement. If you set your shutter speed too long,
your brilliant photo of a distant nebula is going to look more like a big blur across the sky.
So, what do you do about that? You've got two options. You could use a star tracker
to follow the movement of the stars. But those are pretty large, fairly expensive,
and if you've got any foreground in your photos, now the foreground is going to be
blurry. Your other option is just to use a fast enough shutter speed to eliminate
motion blur. With a wide-angle lens, maybe that's something like 20 seconds. But if
you're zooming in with a telephoto, you'll get blurry pictures even at just a few seconds.
And this is the problem. Especially when you're zooming in, you only have a few
seconds of exposure time, and that means you just don't capture enough light. Here,
I was photographing the Orion Nebula, which is one of the brighter objects in the sky,
and I still had to bump up my ISO to 12,800 in order to get a photo
where you can even see anything. And of course, the image quality is terrible.
Now, what about wider angle shots? Photos where you've got an entry-level DSLR and a kit lens.
You're maybe at a 15 second shutter speed, f/3.5. Again, you're just not capturing very much light.
This photo is a best-case scenario, and its image quality is okay, but it's really not great.
So, what are we missing? The photos that you've got so far have no movement in the stars;
that's good. But they do have a ton of noise that really harms your image quality. Unless you want
to use a star tracker, it kind of feels like this is the best you can do. But it's not. There's a
technique out there which is amazing and super useful. It's called image stacking. Basically,
you take a ton of photos, align the stars, and then average out the noise. I'll show you how
to do that, but here's a before-and-after. It's just night and day. Night, and a clearer night.
That said, it is a little harder when you've got something in the foreground like this. You can't
just rotate the photos so the stars are aligned, because then the foreground is going to be out of
place. And that's why we have to use dedicated software for this type of image stacking. There
are plenty of different options for Mac, PC. I've put some links below. Be aware, though,
that if you do want to do nighttime landscape photos with a foreground, you've got to find
software that can isolate the foreground and not rotate it when it corrects for the stars.
Okay, start with the basics. Clear night, low levels of light pollution. If you're planning
on deep-sky astrophotography, three of the easier subjects - other than the moon - are the
Andromeda Galaxy, Orion Nebula, and the Pleiades. It helps to use an app if you want to track where
they are in the sky. Now, you're not going to get NASA-level images of these subjects with just an
ordinary camera and no star tracker, but you can get pretty solid stuff thanks to image stacking.
My photo of the Orion Nebula is a stack of 250 photos, each with a one second exposure. So,
this is about six minutes of exposure time. More would have been better, but after six minutes,
Orion had actually left the frame of my image. So this is what we get. And, actually,
that's pretty important. If you compose your first photo perfectly, but then the stars move,
the last photo in your sequence is going to be totally wrong. So, try to figure out which
direction the stars are moving. You can do this just by taking a couple of test photos.
Now, at this point, camera settings are pretty easy, actually. Set a long shutter speed,
but not so long that you make the stars blurry. It's even more important than normal right
now to avoid any blur at all in the stars. Because when you're blending these together,
your software cannot get rid of star trails. You're stuck with what you've got. So,
take some test photos at different shutter speeds, and really watch out for blur.
Next is aperture. Set whatever you need in order to get enough depth of field. But this is still
nighttime photography, so a brighter aperture is definitely preferable. I'd stick with about f/5.6
at the darkest, although in theory you could use a small aperture like f/11 or f/16 and just stack
a bunch more photos. Then pick an ISO setting that gives you the proper image brightness. It'll
probably be a pretty high ISO, but make sure that you're not over exposing the stars. There
can actually be some really nice color details in the stars that you definitely don't want to lose.
Focus by finding a bright star, or the moon if it's out. And - this is very
important - set your lens to manual focus. You're going to be shooting a timelapse,
and a lot of cameras for whatever reason focus automatically before every picture
in a timelapse. But most cameras can't autofocus on the stars, so you'll end up
with one sharp picture at the beginning, and then everything else is going to be blurry.
Next, set your camera to take timelapse photos on an interval. Pretty much every camera has
that option, although the way to enable it is a bit different from brand to brand. It can help
if you've got a remote shutter release that's meant for timelapse photography.
So, at this point, how many photos should you take? Well, I recommend at least a couple minutes
of exposure, and preferably longer. Here's a comparison between a single 20 second exposure
and a 14 minute exposure. You can see just how drastic the difference is. So, you might need
like 30 or 40 pictures if your shutter speed is 10 seconds long, or maybe even hundreds
of photos if you've only got a 1 second shutter speed. Regardless, when the timelapse finishes,
bring the photos into post-processing. And you should edit them now, but don't do any sharpening
or noise reduction just yet. Export the finished photos to TIFF - or, if you've got hundreds of
them, you might want to do JPEG just to save space - and then open them up in your stacking software.
This video is not a software tutorial, and depending on what you choose,
the process might be a bit different. The one that I'm using for this video is called
Starry Landscape Stacker, but there are tons of good options. And, basically you load the
photos and then tell the software which parts are land and which parts are sky. And then,
if everything goes right, it blends them into one image and averages out the noise.
When you're done, export the file. Open it back up in your post-processing software. And then just
sharpen the photo, get rid of any residual noise, and generally do the rest of your post-processing.
I do, however, want to emphasize that this image stacking technique isn't something that you need
to do all the time. I actually recommend getting everything right in a single exposure if you can.
I'm going to talk about that in a future video. The reason to use this technique instead is if
you have a slower lens or a smaller camera sensor. It can really help. I also like image stacking for
telephoto pictures of the night sky or Milky Way landscape photos with a small aperture.
And there you have it! If you have any questions about astrophotography, leave a comment below.
And if you've already subscribed to our channel, make sure that you hit that Bell icon on YouTube
so you get the notifications properly. I'm Spencer with Photography Life, and I'll see you next week.