View single post by Eric
 Posted: Sun Jul 18th, 2021 13:36
Eric



Joined: Thu Apr 19th, 2012
Location: United Kingdom
Posts: 3642
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jk wrote:
I think that there are several issues in-play here.
1. Questions about why an AF camera misses focus
2.  Is manual focus more accurate than camera AF
3.  How good are your eyes? As we get older our reflexes get slower so what we used to be able to do is not so rapid.  How much will differ between people.

I think the first item is about expectation.
Do you expect your camera to nail perfect focus every time?  I dong think this is realistic but it should be better than you 95% of the time.  
It is also dependent on your subject.  A black cat in a coal cellar with a single 25w light bulb will definitely challenge most/all camera systems.
The difference in mode of working between Phase Detection and Contrast Difference AF systems will also make a difference.  As will maximum aperture of the lens used.

The second item.  That is about how good your eyesight is and whether or not you can see small changes of focus.  There are several aids such a split image and microprism screens in DSLRs but in mirrorless this is not so possible and the aids provided are good but not perfect.

The third aspect is something that is difficult to assess as we all have changing eyesight as we get older but it is a complex set of factors on play.


In short I dont offer a solution only awareness of compromises.
I think AF works well for me most of the time but not always!  Sometimes I miss focus and sometimes the camera chooses a slightly different point to focus on than I thought I chose!  User error or camera error results in missed focus.

The eyesight is a very good point. My wife’s diopter setting on her Panasonic was waaaaay out for my eyes. So when she asked me to take a photo with her camera, I framed the fuzzy picture with the fuzzy focus spot over the fuzzy object and let the autofocus take a non fuzzy photo.

Of course knowing the aperture and it’s depth of field on the sensor size you have, distance of the subject and focal length can help.

Last edited on Sun Jul 18th, 2021 13:40 by Eric



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Eric