p.1 #1 · Autofocus Issue with Sigma 135mm f/1.4 on Sony A1 II (locks on ears)
I’m writing to report an autofocus issue I’ve encountered when using the Sigma 135mm f/1.4 with my Sony A1 II.
The lens works perfectly on my Sony A7 V, and it also performs as expected on my Nikon Z9 when used with a MegaDap adapter. Additionally, the A1 II itself functions flawlessly with all Sony GM lenses, Canon 200mm f/2via the MC-11 adapter, and Nikon 105mm f/1.4 via the Monster adapter.
Given that both the camera and the lens work properly in other configurations, this behavior is a bit puzzling, as neither appears to have an issue on its own.
I’ve noticed that autofocus often seems to lock onto ears or hair instead of the eyes, even in situations where Human/Eye AF is enabled and works correctly with other lenses on the same body.
p.1 #4 · Autofocus Issue with Sigma 135mm f/1.4 on Sony A1 II (locks on ears)
I want to follow up on this. I have the sigma 135. 1.4 with the A7R6 and am noticing something similar. I had the lens sent back to sigma because I thought I had a soft copy, but they tested and found no issues. They emailed me the photo they took of a test chart with the lens perfectly sharp at 1.4. This image was taken with an A7r5. Today I decided to try and take photos and manual focus and low and behold, the images are sharp. It appears to be missing a tiny bit when using AF. If I stop it down to F2, then that's a big enough depth of field so that the image is sharp. Anyone else using this lens/camera combo?
Here is an AF and a MF image
MF
ILCE-7RM6135mm F1.4 DG | Art 025 lens135mmf/1.41/2000s100 ISO0.0 EV
AF
ILCE-7RM6135mm F1.4 DG | Art 025 lens135mmf/1.41/2000s100 ISO0.0 EV
p.1 #5 · Autofocus Issue with Sigma 135mm f/1.4 on Sony A1 II (locks on ears)
Folks that have experienced with that combo, what is the AF mode on the A7r VI; AF-S or AF-C? My non-Sony OEM lenses, like Viltrox, TT Artisan, have issues with the AF-S. Either they don't focus at all or fluttery. But they work fine on AF-C. Fortunately, my Sigma i-Series lenses, on the other hand, behave like Sony lenses, fortunately. The point I am trying to make is that the A7r VI uses a new AF algorithm that makes some non-Sony OEM lenses not quite 100% compatible.
I would suggest doing a test again using AF-C if you used AF-S previously when you encountered some issues. It won't hurt...
