I do mostly outdoor photography and anyone who does this can get bitten by the night sky bug. All those beautiful stars and the dramatic Milky Way beckon, but for many beginners it seems an impossible task. They think of needing tracking mounts, ultra-long exposures, and complicated processing. The good news is, it's not all that hard to get started with a fairly modest investment.
For purposes of this article, I'm going to assume you have a good DSLR, a decent tripod, and can get to fairly dark skies. My focus, so to speak, will be on getting good shots of the Milky Way assuming you are just starting out on your quest.
The key to achieving nice Milky Way images is you're going to need a good lens to do this, and you probably don't own a lens that is going to make Milky way photography easy. The happy solution is a Rokinon 14mm f/2.8 lens (they are branded Samyang in Europe, and they are made in Korea). Usually selling for about $300, they can take excellent Milky Way images, won't require you to invest in a tracker, and are fast enough and have good enough optical quality to produce an excellent image. The lens works well on full-frame sensors and APS-C sensors. Rokinon has been producing this lens for a very long time, and even though the cost is very low for what it does, it is pretty much the go-to lens for Milky Way astrophotography. It's certainly the most popular choice for many photographers.
The Rokinon comes with mounts for many popular cameras including Canon, Fujifilm X mount, Micro Four Thirds, Nikon, Nikon AE, Olympus, Pentax, Sony A mount, and Sony E mount. You'll want the basic Rokinon lens, autofocus really isn't needed for sky photography, and we're trying to get this done with a minimum of expense.
So assuming you have the lens in hand, what's next? The Milky Way is visible this time of year, but it's even brighter in the summer and fall. You'll want a moonless night, and be far away from city lights.
With the Rokinon on your camera, you'll want to set focus at manual and try infinity. The infinity marker is not always exact, so try it at some settings on either side and use what works. Then open your lens to f/2.8. Set your camera to bulb or T for time exposure so the shutter can be held open. Better to use an inexpensive cable release for that, so you aren't really touching your camera, but in real life, if you are careful, the Rokinon image is so wide that small vibrations likely won't appear. You'll need to be on a tripod; no one can hold a camera steady for a shot like this.
Astrophotographers often use the 500 rule to determine exposure time, dividing 500 by your focal length. Since the Rokinon is 14mm, that gives you about 35 seconds, but with modern cameras that rule begins to fall apart. With my Sony a7 III I use 14-17 seconds. My Canon 6D used the same exposure time successfully.
A good ISO would be 3,200 if your camera allows it. With less than a full-frame sensor I might suggest 6,400. But I've seen older cameras do pretty well with 1,600 ISO. Variables are how dark your sky is and how clear and non-turbulent the air is.
The image below was taken with a Canon 6D and the Rokinon with a 14 second exposure at ISO 3,200 and at f/2.8. The yellow glow is light from a nearby city.
Some cameras offer noise reduction, a separate image taken with the shutter closed that runs the same time as your initial exposure. I don't recommend it as it is time consuming and not always effective.
Shoot in raw format, it will allow you to get the most from your image when you post-process it. There are a variety of excellent tutorials for processing Milky Way photos on the web. Some of my favorites are this video and this article. You'll need Adobe Lightroom or Photoshop or any editor that allows you to manipulate raw files. One of the critical things to get right in post-processing is to get the white balance correct. Even far away from cities, the sky will glow with color that comes from city lighting. At the start of any processing session, you'll want to get as neutral a sky as possible.
Image below with Sony a7 III, Rokinon lens at 17 seconds, ISO 6,400 and f/2.8
Chances are, many of our readers will have everything they need to get started getting rewarding Milky Way photos, except for the lens. You can spend more on a wide-angle prime, but the Rokinon really hits the sweet spot. And it does more than just night sky photography. It's used for landscapes and architectural photography too. It's not really a high-end lens, and you'll likely see some vignetting and distortion at the extreme edges of the lens. Those artifacts can be largely reduced in post. I've also heard that some of the Rokinon lenses don't work well out of the box, but I have friends who use them and have a good experience. If you see mechanical or optical issues return it and try again. The Rokinon really is a bargain, but it won't have the build quality of something more expensive like a really fine and well regarded Sigma Art prime. Still, the Rokinon results will be pretty close to the quality you can get with more expensive lenses.
The most important thing is that the Rokinon will get you going, and if you follow the basic rules, you'll get images that will amaze you without a big outlay of cash. Please feel free to share your experiences below in the comments.