Thread: F stops
View Single Post
Old 18th October 2017
RobEW RobEW is offline
Full member
Join Date: Feb 2017
Location: Nottingham
Posts: 2,050
Thanks: 165
Thanked 74 Times in 68 Posts
Likes: 1,198
Liked 194 Times in 132 Posts
Re: F stops

Yes, if you want to let in twice as much light, the three common ways are:

Expose for twice as long a duration
Stop down by one stop (e.g. from f4 to f2.8, or f2.8 to f2, or f2 to f1.4 etc)
Double the ISO speed (e.g from 100 to 200, or 200 to 400, or 400 to 800 etc)

Comparing lenses with different focal lenghts is a rather different matter ...
Reply With Quote
The Following User Says Thank You to RobEW For This Useful Post:
MJ224 (18th October 2017)