Help with A7R3 set up. Back Button and Spot Focus

[pcr1040]

I set my A7R3 up for wildlife and it works fine using "Wide" focus.  I then set up focus using back button (AEL Button ) And then set the AF-On button to single spot focus and there in lies the question and concern.  When I normally shoot I have aperture  set to f8 (becasue the 70-300 G OSS is not very sharp wide open at 300mm) I have C2 set for all of this and ISO floats from 100-800 and I can select a shutter speed.  All of that works well until I use the AEL Button for Spot Focus.  Now the camera let shutter speed accommodate to give best exposure and the F stop is LOCKED to f5.6 and I cannot reset it.   I assume the camera shifted to P mode and favors widest opening becasue usually spot focus is used when the object may be in shadow.  My question is, is there any way to change the f stop when in Spot Focus using the Back Button AEL?  I tried to do this when the AEL is depressed, but the F remains at 5.6. I tried M Mode same thing, F Locked at 5.6.

Any suggestions on what to do here?

Edited January 12, 2020 by pcr1040

[Poly]

For using BackButtonFocus you need to change two parts.

1. 1/6  AF Shutter OFF

2. 1/10 AEL with Shutter Auto

If you put the AF only on the AEL-Button it is still on the Shutter-Button.

That means: Pressing AEL-Button for BackButtonFocus ist overwritten

by pressing the Shutter.

My A7RIII runs perfect with Focusfield enlarged flexible Spot or wide.

[pcr1040]

Poly

I set the camera up as you suggested and I now have a button assigned to spot focus (AF-ON). And the Back focus button is assigned to AEL button.  That is to give me a choice of Wide focus (AEL) and Spot Focus (AF-ON).   Only problem is the AF-ON button will not permit me to change the F stop and the shutter speed varies as a function of the light (Aperture Priority ???).  The current setting is F8.0 and and no matter how I set Mode (P, A, S, M) when I push the button for Spot focus, the f is set to F8.0 and the camera is in apparently Aperture Mode.  Another issue is that I cannot tell what ISO setting is used.  I can use the AF-ON for spot focus if hte object in stationary.  I focus using hte spot then release it and click the shutter.  And that works so long as the object is not moving.  I have a second camera system also set up like this one is with a spot focus (set by menu) .  In that camera the spot focus permits me to set aperture and shutter speed, and use any of the Mode settings.

 I am assuming the my AutoFocus will be more accurate at a larger F stop like F4, is the true?

 

[pcr1040]

Issue resolved.  I got into the sub menus and somehow, I changed something and now it is working.  Unfortunately, I did nt keep track of the changes I made and so, while it is working, I cannot be sure what I did to fix it.  That speakes to the issue fo rht complexity of menus and the ambiguity of how they are labled.

Thanks again for all who tried to help me.