December 6, 2013
Comments Off on Wide Field Astrophotography
What does one do when they either feel bored or out of subjects with terrestrial photography? Turn to the skies. Specifically, the night sky. Wide field astrophotography is gaining popularity due to the relative ease and not having a requirement of knowing anything about astronomy or prime astrophotography.
To get into the practice of taking photos of the night sky, you really only need a digital SLR (or film or even a point and shoot if it has a fast lens and manual settings), a solid tripod and a fast wide angle lens. When choosing a lens, the ideal would be f/2.8 or faster in order to capture more light without the stars trailing. Star trails can be a welcome style if that’s what you desire, but to maintain pinpoints and to gather enough light, you need a fast lens. Fast lenses are typically f/2.8, f/2.0, f/1.8, f/1.4 and f/1.2.
Great lenses on the market these days is made by a Korean company that’s marketed under the names Bower, Rokinon and Pro Optic. Rokinon is the typical brand you’ll find here in the US and they’re much cheaper than Canon or Nikon equivalents and more often than not, produce better results. The Rokinon 14mm f/2.8 allows for very long exposures before stars begin to trail. There’s a rule floating around on the internet and it’s either called the “600” or “500” rule. The premise is to determine how long your exposure can be before stars begin to trail, you take 500 divided by the focal length of the lens. For example, if you have the Rokinon 14mm lens, it would be 500 / 14 which gives you 35.71 seconds. Always round down so simply make it a maximum of a 35 second exposure. This rule isn’t exact but for the most part, will work 90% of the time.
Another thing to consider is your sky. Do you live in a light polluted area? If so, then you’d be advised to find the darkest sky around you. To do this, go to this URL (http://www.jshine.net/astronomy/dark_sky/) and find where you live and check the colors. You’ll want to find an area that’s at least green. Blue is better and dark gray to black is the best. If you’re on the east coast, you won’t find much in the way of black (if at all). If you’re in an area that’s yellow/orange/red then your skies are so light polluted, you may not pick up anything but the brightest stars.
One could go on about this subject but the best thing to do is get your gear and head out and try it. Any result is better than no results so don’t get disgusted if your first photo doesn’t turn out perfect.
You can find links to cameras and lenses on the right. The Rokinon 14mm is listed as well.
If you’d like to see some great resources on the subject, visit David Kingham’s site at http://www.davidkinghamphotography.com/