Is this exeptable edge softness?

[thefonz78]

I just received my tamron 17-50mm and its perfectly sharp in the centre but the edges are very soft. I know wide open is never great on any camera but should i expect from the tamron is the shot below at f2.8 50mm about right i is this not a great copy. There only other lens i have to compare with it is my nikon 50mm f1.4 which is better at the edges but thats to be expected with a prime surely.

http://imageshack.us/photo/my-images/337/dsc2162t.jpg/

[jet_kit]

Difficult to judge with such disparate subject matter. If you can get your hands on some sort of test card it would make comparison much simpler.
Generally speaking, lenses do not perform at their best wide open, nor stopped right down. Also zooms tend to perform better in their mid-range with the worst performance at the top end. Your test shot is probably the worst case for the Tamron; Max aperture @ max zoom.
As you say, primes will always produce a better image. Back in the 'old days', we all carried bags full of primes because the results from zooms were so poor. Technology has resulted in zooms which produce very acceptable images today, but that same technology also enhances the primes, so they'll always be out in front when it come to quality.

[thefonz78]

Thank you Chris yes it wasn' t the best example . I took some wall shots they looked terrible but on you advice i downloaded a test chart. Printing on letter paper isn't perfect maybe could have used photo paper but i've got some results set at 35mm at F2.8 to F11. They look pretty soft in the edges up to f8 i'd expect it up to f4. Is this about right for this sort of lens? Can you please see what you think thank you.

http://imageshack.us/photo/my-images/155/dsc2658h.jpg/
http://imageshack.us/photo/my-images/834/dsc2659e.jpg/
http://imageshack.us/photo/my-images/11/dsc2660m.jpg/
http://imageshack.us/photo/my-images/18/dsc2661n.jpg/
http://imageshack.us/photo/my-images/687/dsc2662h.jpg/

[greenwing]

I'd be more inclined to take a look if the pictures were somewhere that doesn't send me pop-under ads whenever I do anything. Sorry.

Chris

[jet_kit]

I think f8 is definately the 'sweet spot' for this lens, with f11 coming a close second. At both these apertures I would say the overall sharpness is pretty good, although probably not up to the standard of your nifty-fifty.
The next trick is to run another series of tests at different focal lengths through the aperture range. It's a lot of images, but they don't cost anything with digital. I would recommend printing your test card onto good quality gloss paper and try to get some lighting with good contrast. This will enable you to discover the optimum focal lengths and apertures of the lens. With that knowledge you can operate the lens to it's best advantage.

Good luck

[SieSmith]

Found some test reviews for your lens (i hope it's the right one)

http://www.lenstip.com/18.4-Lens_rev...esolution.html

Hope this helps.

Cheers, Sie

[markgozz]

Hi thefonz .

I don't know if this is usual for a lens like this but I think I would feel very hard done by if I had spent good money on a lens that I can't use over a large chunk of it's spectrum , the first two or three sample images are in my opinion unacceptable and the lens at those settings not fit for use .

Mark

[thefonz78]

I wish i tested my kit lens before selling it so i had something to compare it too. It doesn't look good to me either lenstip images at f2.8 look much better than mine. I have 14 days to return so id the general consensus is its not up to par? Has anyone taken similar test shots that i can have a look at?