[davidmanze]

Hey all - many thanks for all the replies! This may be a more complex problem than anticipated, but Dave might be right - I'll run another series of test shots with a tripod and different shutter speeds to see if it makes any difference over the next weeks when I find some time. Will report back.

 

The lens itself already had an oddyssey: I've come to a point where it's "ok" for my personal amateur photo purposes for now. I bought the Tamron new in Germany in April '15, noticed a bad front focus straight away. Back to shop (Media Markt), and they let me try another sample on my EOS 1000D, same issue, but competent sales guy that knew about the issue for a change.

 

Back in Ireland (where I live), contact Tamrom UK Support (Intro 2020 Ltd.) and they honoured the warranty no problems. Sent lens & body in, came back the same way, same front focus. Sent in to Tamron a second time, then they updated the lens firmware again, and also adjusted the following (copy & paste from Tamron UK Support): "the infinity point was moved along with adjustments made to the resolution power.".

Now, with my basic optics & physics school days knowledge moving the infinity point somewhat makes sense to me (I guess by means of moving some lens group slightly), but what could "adjustments to the resolution power" mean? Anybody got any ideas?

 

After the second service attempt the bad FF was fixed, I still seem to notice a slight FF or BF, depending on the focal lenght. Also, I'm just wondering - is that also an expected behaviour, i.e. that different focal lenghts show FF or BF on the same lens?

 

Researching more into possible causes, I think I have (also) found out I got a focus shift issue, was able to reproduce as per http://photography-on-the.net/forum/show...488&page=3 (message #38).

 

Anyway, for now it's ok - love the colours the lens produces in general, and some pictures without VC are really good and sharp, but unfortunately only a smaller amount of pics. And yes, I'm fully aware it's always the combination of a particular copy of a lens and particular body - in my case I had troubles, but will have to research a bit more how to compensate for all the flaws on my combo. Any more tips about the above appreciated

 I read a few of the bloggs from your link, Wow, there some that are really getting their knickers in a twist there! 

 OK, it's worth doing some tests if only to know where you stand in terms of shutter speeds/ AF etc.....good luck!