Tamron SP 300 5.6 problem

I have just purchased one of these, with a 01f t/c on the bay and having run off some test shots I am very disappointed with the results, which are very "fuzzy" and lacking in sharpness. Colour rendition and contrast seem ok. I have a Tokina RMC 300, which I was hoping to sell after buying this one, which is much sharper. It has been my assumption that this SP series lens was of good quality, and I would certainly have expected to outperform the Tokina. In fact I had hoped it would be close to my SMC K 300. I have never used the Adaptall system but the mount appears to go on and off ok so I don't think this is the issue. Does anybody have any thoughts as to what might be wrong. The seller has offered to have it back
with a full refund but I would like to keep it if possible.

the SP 300 5.6 is generally said to be ok (I haven't used one, I only have the rather inferior non-SP version and the monsterous F2. so I'm surprised that it's not performing better than the Tokina.

perhaps if you put up an example or two we might be able to see what the problem is?

Don't be fooled by the SP tag on Tamron adaptall 2 lenses. Be even more wary about the fanciable claims made about these lenses on the http://www.adaptall-2.com/ website. I bought a KA adaptall and then purchased eight AD2 lenses cheap on ebay (I was like the little girl in the proverbial candy store) and boy don't they go cheap. At the time I really thought I was on to something good, I soon found out I wasn't and have retained only one an 80-210mm f3.8-4 a reasonable performer and funnily without the SP tag so for 6 quid delivered - worth keeping on. I'm not saying all these lenses are dogs, in fact some are pretty good but then most are average and 'Superior Performance' is rather a grandiose claim for Tamron to have made.

The SP 35-80mm is a lens some rave about, it is very sharp by zoom standards @ 80mm but doesn't cut it @ 30-60mm at all. The SP 70-210 f3.5 lens much trumpeted on adaptall-2.com are inferior to Pentax and Vivitar series one offerings of the same focal length. The fabled SP 90mm f2.5, is sharp and great for close ups and indoor work but will flare wickedly outdoors. So much so its obvious its better suited to film. The SP 2x tele-converter was among the worst TC's I've ever used.

All in all, I have to conclude my foray into the Tamron SP world was quite disappointing.

I have only bought one Adaptall 2 lens and that was the MF 90mm F2/8 macro. I paid £75 delivered for it on Ebay thinking I was getting just the lens and it turned up with the PKA mount attached, worth around £50 on it's own I believe.

As for the lens, it has been attached to my K10D more times than any other lens, by a factor of around 10 I would say.

I too obtained an sp300mm from Ebay recently and I'm very pleased by the results, it seems a very sharp and contrasty lens to me. I would suspect there is a fault with your example if the results are fuzzy.
I have seen some PF when using it wide open @5.6 on my k20d.

Trying a link here...

http://farm4.static.flickr.com/3263/2511177067_da31b91530.jpg

This does have some PP sharpening applied mind you.

I'm going to have to disagree with Philmerrin, my 2 best lenses are Tamron SP series in Adaptall-2 mount. The 90mm macro and 300mm F2.8 are both stunning in every respect.

The Tamron BBAR coatings aren't up to Pentax SMC standard, but in general use I've never seen either lens flare without good reason.

Me too. The SP 17mm f3.5 is also a superb lens, and incredibly wide on film.

I'm not arguing that some SP lenses are not good or very good, I said so in my post and I quote myself.

"I'm not saying all these lenses are dogs, in fact some are pretty good but then most are average".

But I'm not surprised at what the original poster had to say about his particular SP lens. I'll re-iterate that the Superior Performance on some (but not all) SP lenses is a grandiose claim by Tamron. Buyer beware!