Now let’s get to the important part, camera settings. You will need to take control of your camera, keeping it in Manual mode. Change the mode to Manual and tune in the following settings.
Focal length: Set your focal length to the widest you have – e.g., 18 mm in the case of a kit lens. You can choose any focal length you want, but the more you zoom in (the longer the focal length is), the less stars you will be able to capture, and your optimum exposure time before star trails start to develop will also decrease (500 Rule).
Aperture: Setting your aperture to the widest option is key here – e.g., f/3.5 as in a kit lens. By using the widest the aperture, more light will enter through your lens giving you brighter stars and Milky Way.
Shutter speed: If you are only shooting stars and/or the Milky Way, set the shutter speed to 20 seconds or star trails will start to appear, giving the look of larger, unfocused stars. If you are wondering, why 20 seconds, here is the answer. Optimum exposure before you start getting star trails is calculated by dividing 500 by your focal length (also divide the answer by 1.5 if you are using cropped sensor.) So in the example of an 18mm lens on a cropped sensor – 500 divided by 18 = 27.78 divided by 1.5 = 18.52 (so roughly 20 seconds).
ISO: Start by keeping the ISO at 1600, and increase it later depending on your results. Keep in mind that greater the ISO, more noise there will be in your image. Although it does depend on signal to noise ratio of camera body you are using. High end or even new consumer camera bodies tend to produce less noise at higher ISOs, than do older ones, even three years old.
Shutter release: You need to have a shutter release (remote trigger) to avoid camera shake while shooting. If you don’t have a shutter release remote/cable, just use your camera;s 2-second or 10-second timer. That will minimize any blur in the picture due to camera shake.
It’s also best to switch OFF your “Vibration-Reduction” or “Image-Stabilization”, as the vibration of the motors can cause shake in the picture too.
Focusing the lens to infinity: Next, after putting up all these settings, the next most important thing left to do it focus your lens to infinity. As kit lens doesn’t have infinity marker on it, we will use hyper-focal distance values to focus the lens to infinity. Mount your camera and lens on a tripod, and focus it on any bright object far away at a distance of 20 feet or more. Point a flashlight towards camera from a distance of minimum 20 feet and focus on it if you are in the dark, and don’t have anything to focus. Once the lens is focused beyond 20 feet, its hyper-focal distance will project to infinity and your stars will be sharp. It will also help in getting anything in the foreground sharp too.
Don’t forget to switch your lens to M (Manual) after focusing, or else it will start to hunt for focus again when shutter is pressed.
If your lens is not focused to infinity, you will get the Milky Way but the stars will not be as sharp and will appear bigger. Same can happen if you go for a longer speed than required for not causing stars to produce trails. An example of these mistakes is here.
Lens was not focused to infinity.
Lens was not focused to infinity.
Lens was not focused to infinity.
