What is Astrophotography?
Learning Your Gear
Let’s talk about the camera gear you’ll need to photograph the stars!
- DSLR/Interchangeable Lens Camera Body
- Wide Angle Lens with a low number f rating. 2.8 or lower is best. F4 will work to begin.
- Tripod – Preferably a VERY sturdy one w/o a center post.
- Intervalometer - This is a shutter cable release which has a timer on it. It allows your camera to make repetitive images, say for time-lapse or stacking, and take images longer than 30 seconds.
- Star Charts – Photo Pills, Sky Guide, Stellarium
- Extra Camera Batteries
Where is Infinity on your lens?
Every lens is different so it’s a real good idea to know your lens and know where infinity is. A good way to learn this is to take it out and find the thing that’s the furthest away from you and use your auto focus (during the daytime) to set infinity. I usually think the moon is the best measure for this because it’s well-lit and it’s pretty far away. Once you get the infinity setting for the moon, you can make some minor tweaks for the stars.
Also, here's a great resource for helping focus on stars. It's called SharpStar.
Do you know how to use the Manual Mode of your camera?
- Do you know how to adjust ISO? We’ll be working in dark situations at ISO’s as high as 6400 or 12,800.
- Do you know how to set your Aperture to its “wide open” setting like f2.8?
- Do you know how to set your Shutter Speed to exposures between 15-30 seconds?
- Do you know where the BULB setting is for your camera?
NOW is the time to check your manual or learn, not out in the field on shoot night.
The biggest mistake photographers make in beginning to photograph the stars is not taking a bright enough image. That doesn't mean expose longer, it means a higher exposure level (read higher ISO).
In photography we are taught that higher ISO's are reserved for action, wildlife, sports etc. but for nature photographers shooting at night higher ISO means brighter exposure to capture the stars. Yes, you need a 10-20 second exposure through an f2.8 (or lower) lens, but the ISO really drives a good astro exposure.
WHAT ABOUT ISO?
There's a common misconception that increased ISO means increased sensor sensitivity. It doesn't, it means increased brightness of a photo by increasing the sensor signal. This is an electronics term. (From LonelySpec) Signal is the part of the photograph that we want. Light is signal. Signal is the image. Without the signal (without light), we can have no image. The more light that we can gather, the more signal we have. In general, the more signal, the higher the quality of the photo.
WHAT ABOUT NOISE?
Noise is the part of the photo we don't want. Noise is electrical interference which appears as speckled grain.
Yes, there will be noise, BUT todays cameras do a better job handling noise, AND now there are some real kick butt pieces of software to help reduce noise IF you use the right technique (read Stacking).
Think of ISO as Amplification or Gain.
If you need proof, rather than just believing me, PLEASE read below the articles about ISO. They are from photographers who are also engineers.
Above you'll see the Big Dipper as photographed in a Kansas sunflower field.
Setting up and getting the right exposure.
Unless we have clouds in that direction, we’re going to set up shooting to the North to begin with. I do this for several reasons:
- The Big Dipper is easily recognizable
- It will teach you the easiest way to do Star Trails
ON & OFF times for lights.
It takes your eyes about 20 minutes to adjust to the dark once you’ve turned off all the lights, so headlamp and flashlight use will be kept to a minimum. You should only turn your light on when the OK is given to the group.
THE SETUP PROCESS
- Setup your tripod and frame your prospective shot to the North.
- Remember that composition is still important at night. You need to have a good foreground to make the stars pop!
EVERYONE SHOULD BE SHOOTING IN RAW, Right?
- ISO – 3200 (Don’t worry about noise, there are remedies for this)
- APERTURE – F2.8 OR LOWER
- SHUTTER SPEED – 10 SECONDS
I recommend that the noise reduction settings on your camera be turned OFF.