Quote:
Originally Posted by obsidianphotos
Ah yes the good old "600 Rule". I have a blog post here http://www.capturingthenight.com/blog/?p=12 on how I use it for my fixed tripod night sky scapes. Personally I use 500 or less when imaging. It's not perfect as stated, but it's a pretty good guide.
With your new 650D being a non frame camera then you need to factor that into the equation as well Jonathon, but yeah you don't need to worry about the aperture. Canon's crop factor is 1.6, so with your 8mm it is effectively (for the purpose of the 600 Rule) 12.8mm (8 times 1.6). 600/12.8= 46.8 seconds maximum shutter speed before the stars trail too much to be really noticeable. As I said I tend to do the 500 rule or less. 500/12.8= 39 seconds but for that lens I would just stick it on 30 seconds. |
Great explanation on your blog Greg - thanks for taking the time to put it together. I feel that the resolution of the chips is beginning to give some of these equations a hard time as even 30 seconds on the 18mp aps-c chip is pushing it let alone 45+ which would provide a clear streak.
However, I have a way to go yet before streaky images are my primary concern
