All Forum Comments
Comment by pschlute posted on Focus shift - can live view focus stopped down? at 25/10/2019 - 13:25
Comment by pschlute posted on Berlin (4) Botanical Garden at 24/10/2019 - 23:06
But the most popular fix for this problem is to convert the lens to screwdrive.
Comment by pschlute posted on DA* 16-50 SDM motor repair? at 24/10/2019 - 23:02
Comment by pschlute posted on New lens - Sigma 70mm at 24/10/2019 - 22:30
Comment by pschlute posted on Focus shift - can live view focus stopped down? at 24/10/2019 - 22:28
Comment by pschlute posted on Hello from Kentucky at 24/10/2019 - 22:21
Make the camera focus each time from infinity alternating with closest focus distance. Then compare the results. This will tell you if your AF system needs adjusting.
I am afraid those picture are too small to draw any conclusions.
Comment by pschlute posted on Focus shift - can live view focus stopped down? at 24/10/2019 - 18:44
The actual focus plane should remain the same whatever aperture you choose. Can you post some large scale examples
Comment by pschlute posted on Focus shift - can live view focus stopped down? at 24/10/2019 - 15:06
I did not have to travel far to capture this chap. British wildlife centre in Surrey. It is a picture from a couple of years ago with a bit of new processing.
Comment by pschlute posted on Here Kitty Kitty at 21/10/2019 - 20:19
Comment by pschlute posted on Here Kitty Kitty at 21/10/2019 - 19:45
It gets weirder. I've just tried at 270mm and found that the camera focuses slightly differently as you stop down. This suggests the firmware attempts to compensate for the focus shift.
I never realised the camera took account of the aperture when focusing. It's cleverer than I thought. Only problem is, it compensates in the wrong direction! At f/16.0 it sets the focus slightly closer than at f/6.3 (wide open), yet what we want is for the focus to be set slightly further back. Ah well!
It's not good for your health to investigate these things too deeply.
Are you testing this scientifically ? At least 10 attempts for each setting otherwise the vagaries of AF accuracy (ie not very) come into play.