I took this picture today in Dubrovnik, Croatia. I used a 100-400mm Canon lens set to 164mm and used an aperture of f/5. All lenses go to infinity at some distance from the shooting position; this means that once the lens is focused to this point, no further adjustment is necessary to focus on subjects beyond that distance. In other words, a lens aperture of f/5.6 will give you the same depth of field that f/22 will provide when focused to this 'optical infinity' distance. Since the larger aperture allows a lower ISO and a faster shutter speed, it is better to use the larger aperture rather than the smaller one given that the photographic results will be the same.
3 Comments
May 8, 2016, 6:39:09 PM
Bryan - Thanks. I'll check it out.
May 8, 2016, 2:27:49 AM
Jim Zuckerman - Hi Bryan,
This works mostly for lenses 50mm or less. It is not a perfect mathematical formula, but it's a workable guideline. For the precise calculations, you can use this link and plug in the various numbers:
http://www.dofmaster.com/dofjs.html
Jim
May 7, 2016, 9:39:09 PM
Bryan - Jim,
Is that part of the lens specs, a formula, or do you just have to experiment to find it at different focal lengths?
Bryan