How to favour exposure time over ISO?
So let’s start the ball rolling. This is a question that has been asked in many different guises on the TLV FaceBook page.
Supposing we know what the final exposure should be for a night exposure (good old 500 rule) and we want to keep the ISO as low as possible, how do we config that?
In my experience I often end up with an exposure time lower than my target and an ISO that is higher. The overall exposure is often correct.
“powers of 2” could explain a great deal. Does that however imply only 2/4/8/16/32 etc? But I typically end up with 20 sec shutters.
So a desired shutter speed of 25s would also require a 36 sec interval? Would a 24s shutter speed only require 28 sec or would that also need a 36 interval?
I would be very happy with a shutter speed of 24s and an interval of 28s.
If that is true my problem is how to set 24s as my Nikons only allow 20, 25 and 30s shutter speeds.