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Tamron 50-400 sometimes refuses to autofocus

  
 
hasenbein
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p.1 #1 · Tamron 50-400 sometimes refuses to autofocus


Hello, has someone also experienced this problem?

Sometimes my Tamron 50-400 (firmware 04,on A7RV with firmware 4) stops autofocussing in the middle of shooting. I have to switch the camera off and back on, then the AF works again.

Any advice?



Jan 14, 2026 at 03:43 PM
jtra
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p.1 #2 · Tamron 50-400 sometimes refuses to autofocus


My 50-400mm never showed this problem with A7RV, firmware 2.
Usual advice would be to clean contacts on the lens.

There are contact cleaner fluids. Often with isopropylalcohol. I do not have experience with those. I would be careful to avoid contact of the fuild with the rear lens element to avoid damaging its coatings.



Jan 14, 2026 at 04:35 PM
Newsonys
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p.1 #3 · Tamron 50-400 sometimes refuses to autofocus


using it on my a7c2, never had an issue.....


Jan 21, 2026 at 04:48 PM
nineblade
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p.1 #4 · Tamron 50-400 sometimes refuses to autofocus


hasenbein wrote:
Hello, has someone also experienced this problem?

Sometimes my Tamron 50-400 (firmware 04,on A7RV with firmware 4) stops autofocussing in the middle of shooting. I have to switch the camera off and back on, then the AF works again.

Any advice?


No complaints on AF on the Tamron on Nikon. Only complaint is slight softness, but the lens is otherwise a workhorse.



Jan 21, 2026 at 05:08 PM
Membler
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p.1 #5 · Tamron 50-400 sometimes refuses to autofocus


I have the same issue on my Tamron 35-150 lens on my A1.

Mike



Jan 22, 2026 at 08:37 AM







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