Autofocus Problems With the 24-70 2.8 G-Master

I bought a 24-70GM "used" last year. I put quotation marks around used because according to the original owner it had never been mounted on a camera, and only took it out of the box because I asked him to send me pictures of it. It arrived in the original packaging, and the lens hood was still shrink wrapped, so I believe him.

Anyway, for the past few months I've been noticing focusing issues on this lens, but only in very specific situations. Usually it only messes up at exactly 70mm, and it's usually when my subject is smaller in the frame, like a single person filling up 1/4 of the frame or less. To combat this problem if I notice an image is out of focus, I'll dial back the focal length and it almost always works fine. Even an image that it's out of focus @ 70mm is usually fine at 67-69mm. Up until yesterday, that was really the only focus issue I had with this lens. I shoot with an A9, so the camera focus should be just fine. On top of that I don't remember a single AF complaint I could have with any of my other lenses. Even the 10-18mm aps-c lens is spot on in almost every situation on the a9.

But yesterday I had nothing short of a catastrophic autofocus failure on the 24-70. The focusing issued were no longer just at 70mm, but at pretty much every focal length.

I was shooting very basic portraits of a groom, and groomsmen, and all of a sudden the AF could not get anything even close to right. We were in shade with a bit of backlight, but nothing the lens and camera shouldn't have been able to breeze through. There was plenty of contrast, and it should have been easy to pick up on the eyes with Eye AF (which I was using). But it couldn't do it. It worked just fine until I got to individual pictures of the groom with his groomsmen, and then it failed 100% of the time. Worst part was it registered that the eye was in focus on the camera. Thankfully I noticed it and switched to manual focus and got the shots. I'll post a few examples below so you can see the type of lighting I was dealing with.

I'm a member of Sony Pro Services, but since I bought this lens used does that void it's warranty if there is something wrong with it (because it's pretty clear there is). Should I try to get in touch with the original buyer and see if he's got proof of purchase still?

Sorry to hear that Jarvis, it does sound odd. Mine has been ok at all focal lengths and I haven’t read anyone Having this issue so sounds like your lens has an issue as opposed to design fault. I would contact the seller and ask but also contact Sony support too and say you can’t find the receipt - double pronged attack sort of thing. Hopefully they don’t require the receipt and just sort it for you

xpfloyd wrote in post #18598760
Sorry to hear that Jarvis, it does sound odd. Mine has been ok at all focal lengths and I haven’t read anyone Having this issue so sounds like your lens has an issue as opposed to design fault. I would contact the seller and ask but also contact Sony support too and say you can’t find the receipt - double pronged attack sort of thing. Hopefully they don’t require the receipt and just sort it for you

Thanks. I did get in touch with the person I bought it from to see if they still had the receipt. I think I'll also get in touch with SPS and see what they say.