Odd behavior with Sigma 150-600C + MC-11 (EF/E) on A7R4a

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SQLGuy
SQLGuy Forum Pro • Posts: 11,775
Odd behavior with Sigma 150-600C + MC-11 (EF/E) on A7R4a

I recently upgraded from A7R2 to A7R4a. On a trip a couple of weeks ago, I took the MC-11 and Sigma 100-400C, plus some other lenses. The MC-11 and 100-400C worked very well on the A7R4a during that trip.

A few days ago, since someone was asking questions about 150-600 lenses, I tried my 150-600C on the MC-11 and A7R4a and ran into some issues. During just a few minutes there were a couple of times when the lens just stopped trying to focus. Switching modes, or switching AF>MF>AF, made no difference. At one point I shut the camera off, and it wouldn't turn back on. In all cases, dismounting and remounting the lens/adapter reset things.

I had thought that everything was on latest firmware. It turns out that the camera and lens were, but the MC-11 was one or two versions older than latest. After updating to the latest, I am not seeing such issues anymore. I don't see anything in the Sigma change log for those last two versions regarding compatibility with the A7R4a (or any specific camera), but the update does seem to have fixed things.

Anyone else seen similar issues?

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A7R4a with SEL2470Z, 55Z, and a number of adapted lenses (Canon FD, Minolta AF, Canon EF, Leica, Nikon...); A7R converted to IR.

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