AF modes on the a7S

Samuel H

Samuel H

Major Contributor
I just got my first AF lens for the a7S (the FE 35mm f/2.8) and I haven't been able to configure it as I want.

I want it to do an AF search if I half-press the shutter button, and stay there, no matter what, until I half-press again. This would allow me to set focus before the take, and go on with that or use DMF (direct manual focus) to re-adjust during the take if needed.

I've tried single-shot AF, continuous-AF and DMF, and none works like that. The best I've been able to get is that it works like that while not recording video, but then when I start recording video it switches to continuous AF.

AF seems to be pretty bad on the a7S in video mode to begin with (test), if I can't even configure it how I like it, it's just useless.
 
I film two of my websites with the A7S + kit lens and basically do what you describe, but instead of the shutter button I use the AF/MF button on the back of the camera, the one near the top. By default it's configured as a toggle, I changed it to only work when I hold that button down. Along with that I have the AF mode set to manual and to focus on a medium sized square rather than the entire scene. So basically I point that rectangle at what I want focused, hold the AF/MF button until the auto focus grabs it which it normally does on the kit lens quite nicely, then release that button, re-frame and record. Then it holds that focus while I film and it won't change until I press that button again. That sounds like what you need correct? Except that I use that af/mf button instead of the shutter button. That's worked well for me on over a dozen shoots so far, I can focus and film, then quickly re-frame focus and film again in an instant without disturbing the actors. It's basically three default settings that I had to change, I had to set the camera as manual focus, change the af/mf button on the back to perform auto focus when pressed, and set the focus point as a medium square.
 
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It worked perfectly.
Now when I set the little switch to AF/MF, if I press the button it focuses, and when it's not pressed it stays where it is. Both recording and not recording. As I wanted.
Thanks a lot.
 
In my experience, the only downside to face recognition is that at an angle, faces sometimes fail to be recognized. Prescription lenses also pose a challenge for face recognition. In spite of this I leave it on most of the time. :-)
 
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