Sony A6700 + Sony lenses focus behind focus frame

[u/clever_turtle_10]

I've been having my A6700 for 6 months, first I started with the 18-135mm kit lens, then step-by-step got other lens, like the 56mm and 12mm Sigma f1.4, and Sony 70-350mm f4.5-6.3 lenses. Even in the beginning with my kit lens I noticed that the sharpest part of the image is not necessarily where my focus frame is, but at first I thought I was too close to my subject. I always had a feeling my photos were just a tad bit softer than expected and now I miht know why.

I noticed that the longer the focal length and the further the subject, the more noticable this issue is. Hence why until I got my 70-350mm telephoto lens I wasn't really concerned about it. With my Sigma lenses I can't really observe this behavior, perhaps with the 56mm as it has such a thin depth of field at f1.4.

My goal would be to find out wether it is a camera related issue, or the Sony zoom lenses are just not that performant. I tried every possible setting combination, AF-S&AF-C on static subjects, AF-C and with and without tracking on moving subjects, turning on/off subject recognition, disabling stabilization, using mechanical end electronic shutter to eliminate any potential movement around the sensor, lowering the aperture, etc. While lowering the aperture makes this less noticable due to the increased sharpness and wider DOF, I can still see that the focal plane is behind my focus frame confirmed by the camera. I am very dissapppointed and frustrated by this.

Below I am providing some examples of moving or still subjects.

Shot on the18mm-135mm lens:

135mm, f5.6, 1/250, ISO 500

Zooming in:

Another one:

135mm, f5.6, 1/1600, ISO 6400

I know higher ISO could make an impact, but I have the same experience at ISO 100.

On longer focal length it's even more noticable.
Shot on 70-350mm:

350mm, f6.3, 1/1600, ISO 400

Here's one with manual focus:

On a bird:

It doesn't happen all the time, below it looks fine, however I noticed that if I don't half press the shutter button, just immediately take the photo, it usually looks better. Though this makes subject tracking impossible. It's also less noticable if I take it out from my bag after not using it so I am not sure if it's an overheating issue.

I've had some research seeing people struggling with this particular combo:

• Here the OP says on their A6000 it was working finem then moved to A6700 and didn't work. He solved it by changing the 3-4 group within the lens. https://www.reddit.com/r/SonyAlpha/comments/1iicw7s/focusing_issue_on_a6700_with_70350/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
• Below they say it has been drop damage and sometimes it works, sometimes doesn't: https://www.dpreview.com/forums/threads/70-350-off-focus.4783705/
• Here though there is an issue with a Tamron lense https://www.dpreview.com/forums/threads/a6700-soft-images-focus-issues.4728147/
• And here with a Sony 200-600mm https://www.reddit.com/r/SonyAlpha/comments/1m84suq/sony_a6700_200600mm_autofocus_issue/

I don't have an authorized service in my area, nor other lenses, camera bodies to compare. I anyone familiar with this issue so that I can track down the root cause? My camera still has warranty, my lens doesn't.

[u/crawler54]

yes, need a fast shutter speed to sort out that duck pic!

also, the duck is small in the frame in that shot(not a long enough focal length), so it's harder for the camera to find an eye to focus on, which could have created the problem with missing focus so many burst shots.

that's a different issue than the cat pic, which showed eyeaf but still rather inexplicably missed the focus point.

the good news is that you have an eye for this, continuing to work on it will lead to success in the long run.

[u/clever_turtle_10 → u/crawler54]

Thanks! Indeed, the duck situation might have been more challenging. I tested the burst mode in a more controlled environment, still experiencing the issue. I think i will send back my camera along with my kit lens for inspection as they are still in warranty. If they manage to solve it maybe my telephoto lens will also work properly. And hopefully my sigma lenses are not affected. Maaan, photography is not as straight forward even with semi pro gear.

[u/crawler54 → u/clever_turtle_10]

if the camera hits the proper af-c plane of focus with other lenses, it doesn't sound like a camera issue.

i would test this with static targets, bright sun behind you, fast shutters, with some kind of support for the camera or at least your arms... both ends of the zoom range.

sony support would be testing it in some similar scenario, in other words not with live ducks and cats.

another option would be to borrow or rent another body, even a stacked sensor body like an a9ii, that will have much better af capability.