Samyang 35/1.8 vs Sony 35/1.8

Started 6 months ago | Discussions thread
QuietOC
QuietOC Veteran Member • Posts: 5,777
Re: Samyang 35/1.8 vs Sony 35/1.8

brick33308 wrote:

QuietOC wrote:

Not so much speed as accuracy. Comparing some test images where I used AF-S the Samyang's focus was off in a few. The very low amount of breathing on the Sony also makes focusing look better.

I don't follow. Isn't accuracy a function of the AF function of the camera? The lens simply needs to quickly move to the focus point determined by the camera I would think. Is that incorrect?

There seems to be some coordination issue with many third-party lenses and Sony's AF algorithms. The contrast-detect cycle seems to stop just off of ideal with the third-party lenses, while Sony lenses hit spot on every time. This is easy to see when using autofocus with the focus magnifier on a high contrast target. The third party lenses either back or front focus depending on where the focus started from.

There are sometimes issues with Sony lenses too. The FE 1.8/85 would often just refuse to focus in AF-S for me on the A7III. Maybe the camera was mistaking structure in the out-of-focus for a focused subject. I didn't find that behavior when using that lens on the A7RII. An adapted Canon EF 85/1.8 USM I had would focus quicker and more reliably on the A7III. I keep looking for a Sony firmware update to address this issue. I probably should have reported it.

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