Night photography

canuck257

Senior Member
As I understand it, the "600 rule" states that 600 divided by the lens focal length gives the maximum exposure time in seconds to avoid star trails. Does this apply equally to FX ad DX bodies or does a crop body require an adjustment based on sensor ratio?
 

oldmanjim

Senior Member
Great calculator, Wayne. Thanks for posting! Now I know how to fix night shots to eliminate blurry stars - or how to capture them if I want them.
 

WayneF

Senior Member
Thanks. It seems useful to me too, to look at all of the details. On a fixed mount with full size sensor, the 412 Rule will match limits with what we expect from our Depth of Field sharpness rule (CoC). Which is possibly slight overkill sometimes, but for a DX sensor, that is a 267 rule, which is not much exposure.

What it boils down to is that our widest lens (shortest focal length, 12 to 20 mm) will give the best Milky Way results on a fixed mount.
 
Top