The customer has got a used Tamron 17-50 F2,8 lens, and realized that using with a Canon strobe, there is no change on the strobes display, it shows always 17mm focal length.
I was sure that there has to be something with the zoom position brush, so I disassembled the lens.
When moving the zoom ring, I could feel that the zoom tube does not follow too tight the ring. This happens, when the follower, a casted metal parts sits not strong enough on the ring, loosen screws.
But what I have found in the inside, was more over my expectation….
In the inside of the lens there was no zoom-brush – and no flex cable at all.
And as flex cables usually dont sublimate… The seller has forgotten to tell, that the lens is a repaired one, better to say, assembled without repair.