Tamron 17-50 with wrong Focal Length value

Using the Tamron 17-50 and Canon 430EX II with straight flash, I detected that my flash isn't capable of reading the correct Focal Length.
I confirmed with exif info that Focal Length was wrong.

I tested 2 bodies and others lens. The problem is with Tamron.

Does anyone knows more info what may be happening?

How wrong is the EXIF data? Just a little bit off from the markings, or can it not even reach the extremes (i.e. full-wide is > 17mm or full zoom is < 50mm)?

It's it's a long way off then the lens probably has some issues with the method it uses to detect focal length setting (probably a bunch of little internal electrical contacts that make contact based on rotation).

For two shots made at 17 and 50, the Exif info says: 32mm for both.

Touching and pressing the lens, while observing the flash, sometimes the correct value is displayed.

OK then yeah it sounds like the lens has an issue. It's probably quite a minor problem but also a fair bit of work to get to the part to fix it. If you're not confident pulling a lens apart to fix it then you'll either have to live with it or send it to a repair centre to get fixed.

Are the contacts on the lens dirty/corroded?

Thank you all for the input.

phreeky wrote in post #12741651
OK then yeah it sounds like the lens has an issue. It's probably quite a minor problem but also a fair bit of work to get to the part to fix it. If you're not confident pulling a lens apart to fix it then you'll either have to live with it or send it to a repair centre to get fixed.

Any guidelines to perform this task (repair)?
I'm buying other lens to replace this in the next moth - not because of this, but more for an upgrade. If I have some instructions I may attempt to repair it, otherwise I may will leave it as it is.

Snydremark wrote in post #12741750
Are the contacts on the lens dirty/corroded?

It looks normal. I've already cleaned it.

Just curious here, but is in the VC or Non VC model? I have a Speedlight, and no problems, but I have the Non VC model of the Tamron.

David

It's the non VC model.

I don't know what may be happening, but they do have a 6 year warranty, so I would send it back.

David

I fixed my lens! YEAH!

I dismantled the lens to solve some looseness with zoom - I always had this problem, and only a few days ago I looked to the back of the lens while zooming, and realize there was some loss bolt.

After reassemble the lens, I tested it and the problem with the wrong focal distance was solved.

I'm guessing the problem was with some connector.
I'm happy. I didn't broke my lens (it was tough to plug the ring of plastic that has the MF/AF button on place) and I fixed it

canongrip wrote in post #12883271
I fixed my lens! YEAH!

I dismantled the lens to solve some looseness with zoom - I always had this problem, and only a few days ago I looked to the back of the lens while zooming, and realize there was some loss bolt.

After reassemble the lens, I tested it and the problem with the wrong focal distance was solved.

I'm guessing the problem was with some connector.
I'm happy. I didn't broke my lens (it was tough to plug the ring of plastic that has the MF/AF button on place) and I fixed it

good deal! and really good thinking on your feet there.....

Enjoy.