Never use with Panasonic S1H and I am very satisfied so far. You get a lot for the price. I've seen some previous shots of this lens on various mounts showing a lot of vignetting wide open, but they seem to have fixed it because I can't see much now. Deviations/edges may occur depending on the recording. However, I had to zoom the image in by about 200% to make it stand out (and I also used 6k S1H mode). At f/2.0 it drops off sharply, which I think is optimal for this lens. 1.4 can certainly be used, but 1.8-2.0 is sharper and eliminates a lot more of the purple/green fringing that might appear on some subjects. The autofocus isn't the best, but that's pretty normal with third-party lenses like this. I use manual focus anyway (you're good at it with Panasonic cameras). It's fast enough for the short focus references I do. It has a tendency to back focus, as some Sigma lenses do. You get better optics from a more expensive 1.2 lens. So if that's in your budget, go for it! But for me, and using 4k video, the $700 price difference isn't worth an ounce of depth of field and better optics. However, if you primarily shoot with a higher resolution camera, I would recommend upgrading to a more expensive lens.
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