SL3 Zone autofocus locks on subject outside of zone

[Manicouagan1]

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There is a cryptic statement in the SL3 manual that autofocus when set to "zone" can lock on a subject outside the zone.   I believe that can occur often when the area outside the sone has lots of contrast or "busy."   My current solution is to not use "zone" autofocus and use "field" instead to control autofocus.  Are there other solutions to preserve preserving functionality of  "zone" autofocus?

 

[LD_50]

4 hours ago, Manicouagan1 said:

There is a cryptic statement in the SL3 manual that autofocus when set to "zone" can lock on a subject outside the zone.   I believe that can occur often when the area outside the sone has lots of contrast or "busy."   My current solution is to not use "zone" autofocus and use "field" instead to control autofocus.  Are there other solutions to preserve preserving functionality of  "zone" autofocus?

 

Are you having this actually occur in use? 

[Manicouagan1]

Yes    I had a series of photos taken with "zone" focus with a distant subject frames by closer subjects.  These were often landscapes with vegetation in the foreground or subjects framed by trees.   The actual plane of focus was all over the place, generally in the foreground but way outside the area covered by the zone system markings in the viewfinder.  .   At first I thought the behavior was like the focus system in the Nikon D850 SLR which systematically focuses on the nearest subject with in the selected active area of the autofocus.    Review  showed the focus place selected by the camera did not simply pick the nearest  point.  I reread the manual version in English and tried to parse the wording to develop an operational solution.   I found that if I only used "field" setting and none of the subject detection settings, I could achieve consistent  behavior.  In challenging situations now use the SL3 autofocus only in the "field" setting only focusing on a specific spot much as I did for years with my viewfinder M series Leicas.    

[jaapv]

One thing I noticed on the 601, although not on the 2S, is that it seemed to have a tendency to lock on the part it locked on before, in case of doubt, a kind of AF memory effect Could it be something like that? 

[LD_50]

I just tested SL3-S with 35 SL APO in zone focus, with MF and back button control using AFc. In no cases could I get the system to lock in on anything outside the zone. 

I am on FW 3.1.1 and I tried my yard (grass, trees in distance, objects in foreground with higher contrast, objects in foreground with lower contrast) and various scenes indoors. 

Edited June 26 by LD_50

[jaapv]

As I said, only in cases that the camera had a choice I.e. inside the zone