I'm watching this thread with interest. It seems amazing to me that a lens could make it through field testing with a glaring fault such as this? Quite disappointing really.
I would mainly be using it for larger subjects such as cars and aircraft, but it would definitely be used for BiF as well.
Tamron UK asked me to drop them an email detailing the issue, which I did last night. At the time they were unaware of the issue. I sent them my test results against the Sigma 150-500, with the link to my Flickr site, so hopefully should get some joy there! In the real world I'm not sure how much this issue will affect my photography, I guess time will tell, but at the end of the day I've got a hand held, 600mm, with vc that looks like it can do battle with some 'L' lenses IQ-wise, for under £1k. That I may have to 'bump' the focus if a bird is flying away/towards me is something I can probably live with.
jj_glos wrote:
I'm watching this thread with interest. It seems amazing to me that a lens could make it through field testing with a glaring fault such as this? Quite disappointing really.
I would mainly be using it for larger subjects such as cars and aircraft, but it would definitely be used for BiF as well.
Many thanks to you all for providing this info
Tamron buys a license from Canon and other manufacturers where Sigma reverse engineers their lens, see link below as one of many who relay this information. If anyone was having trouble, you'd think that Sigma would be the one not Tamron.
Make certain to contact Tamron service for support issues on AF problems, they are most willing to listen and help. My service tech was most sincere in hearing what we are experiencing........
I don't think canon will update the firmware on the 7 D again . Since there are none in stock , they may be working on a fix now .
I hope so , I can not / will not be getting before March , so here's hoping .
since this lens is f/6.3 max at anything over about 450mm, could that be part of the problem with the Canon bodies, which require f/5.6 or greater for AF to work reliably (except for the 1-series)?
squirl033 wrote:
since this lens is f/6.3 max at anything over about 450mm, could that be part of the problem with the Canon bodies, which require f/5.6 or greater for AF to work reliably (except for the 1-series)?
Always a possibility but it should at least try to focus. Even back when I used to have to tape pins on my TCs to trick the camera for my 100-400 with 1.4TC, the camera at least tried to focus all the time...although the response was jerky and weird but still worked most of the time. This Tamron isn't even trying from the reports I've read. (note: I don't own the lens).
squirl033 wrote:
since this lens is f/6.3 max at anything over about 450mm, could that be part of the problem with the Canon bodies, which require f/5.6 or greater for AF to work reliably (except for the 1-series)?
Not really. The f/5.6 limit is a SW limitation Canon uses to make some differentiation between its amateur and prof cameras. It is a common trick to use a taped teleconverter (taped so the lens (which reports the aperture to the camera ) doesn't 'know' it is mounted on a TC).
The tamron reports its own aperture as f/5.6 even when it is 6.3 in order to tease the camera around this obstacle.
ClausC wrote:
Not really. The f/5.6 limit is a SW limitation Canon uses to make some differentiation between its amateur and prof cameras. It is a common trick to use a taped teleconverter (taped so the lens (which reports the aperture to the camera ) doesn't 'know' it is mounted on a TC).
The tamron reports its own aperture as f/5.6 even when it is 6.3 in order to tease the camera around this obstacle.
ah... good to know. i knew about the taping-the-contacts trick, but was wondering if there was an issue with the Tammy's max aperture at full zoom... thanks!
squirl033 wrote:
ah... good to know. i knew about the taping-the-contacts trick, but was wondering if there was an issue with the Tammy's max aperture at full zoom... thanks!
And you don't need to tape the contacts if you use a non-reporting TC. And with this Tamron lens, I believe my Kenko reporting TC even works with this lens without taping any contacts.
