tamron 28-75 seems to be soft, left of center at 28 and 35mm

[cactusclay]

I just bought this lens and did a little test and found that the wide end was soft when magnified. Is that normal? It was soft from 2.8 thru 8.0. I'm wondering if it is just because of the magnification from the wide angle, which is more than it is on the tele end. Anyone else have that problem?

[tpinchback]

do you have any examples?

[HJMinard]

Not me. Mine varies from sharp wide open to very sharp by f4.

Unfortunately, it seems about 10% of these lenses are duds (very unofficial number based upon feedback on this forum), so you may be one of the unlucky. You should consider requesting a replacement from your vendor.

[wolf]

That lens shouldn't be soft wide open. I did some tests when I got mine, at 28mm - f/2.8 it is sharp when viewed at 100%.

[cactusclay]

Thanks for the reply. I don't have examples, but I can decribe it. I shot a box with writing on it and when I zoomed in on the writing at 28 and 35mm the letters were blurry, all the way up to f8. the d20 was on a tripod. I hate to send something back and just hope I get a better one. I read somewhere that you could send the lens to Tamron and they would fix it right. Anyone know anything about that?

[pcasciola]

I'll second HJMinards 10% bad copy estimate. It may be even higher than that at this point. There was a very recent thread where POTN member kawter2 had a similar experience with the Tamron 28-75mm wide open but at about 50mm. A couple of us posted our matching pictures, he went out and bought a 2nd one and the difference was amazing. I believe he returned the 1st one for a refund after he made sure he had a good copy the 2nd time.

Here's the thread:
http://photography-on-the.net/forum/showthread.php?t=51644

[cactusclay]

Urrrggg. Yea, after looking at those other thread shots, I have to say that I got a bad one. Now I'm thinking that maybe I should send it back and get a 85 1.8, or take the serious plunge and get a 24-70 2.8, so I hopefully don't have to roll the dice again. I just opened a portrait studio a couple weeks ago and have been using my 17-40 f4 and my 50 1.8, but I've been doing to much draging the tripod back and forth and feel like I need a longer portrait lens.

[kawter2]

There was a very recent thread where POTN member kawter2 had a similar experience with the Tamron 28-75mm wide open but at about 50mm. A couple of us posted our matching pictures, he went out and bought a 2nd one and the difference was amazing. I believe he returned the 1st one for a refund after he made sure he had a good copy the 2nd time.
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YUP!! Don't be afriad to take it back.. if they don't exchange it demand a refund and take your business elsewhere. I was told by the first vendor that "The Tamron lens is incompatible with the 20d"!!!!!! can you believe that!

[pcasciola]

Urrrggg. Yea, after looking at those other thread shots, I have to say that I got a bad one. Now I'm thinking that maybe I should send it back and get a 85 1.8, or take the serious plunge and get a 24-70 2.8, so I hopefully don't have to roll the dice again. I just opened a portrait studio a couple weeks ago and have been using my 17-40 f4 and my 50 1.8, but I've been doing to much draging the tripod back and forth and feel like I need a longer portrait lens. You could roll the dice two more times, throw away the worst 2 out of the 3, and still have about $100 left compared to getting the 24-70L. Or, better yet, just exchange the Tamron AND get the 85mm f/1.8, and you'll still save about $500 compared to the price of the L.

The 24-70L is not all roses either. I've seen CA problems on that lens that I've yet to see on the Tamron, and the sharpness is not much better on the Canon if at all. I actually prefer the Tamron, anyway. The Tamron's focus is a little slower and build quality is obviously worse, but it's much more compact and far lighter than the Canon.

[cactusclay]

Yea Phil, I know what you mean. I've been reading a lot of mixed reviews about the 24-70 L and actually was going to bid on a 28-70 L on ebay, because it had better reviews, but getting a used lens sight unseen is sort of scary, that's why I opted for the Tamron. My problem is I could have used the lens today and now I have to wait, but I need to make a decision, before I even start waiting. There was another guy had a 85 1.8 that was having problems on this site and wondering if it was compatible with the 20d. you heard anything about that?

[pcasciola]

I just noticed that about the 85mm f/1.8 after my last post too, which is a little scary because I was actually just about to order one in the next day or two. I haven't heard about that focus issue yet with the 20D+85mm f/1.8, but I think I'll hunt around for more info before I order it now.

If you rely on these lenses for your business, then maybe the Canon 24-70L or 28-70L is a better choice for you, because I could see it outlasting the Tamron for sure. If you're afraid of buying used, check out KEH. They have a pretty good reputation and always have a good stock of used L glass. Here's a link to their Canon zooms page. They are showing four used 28-70L's in the $850 - $950 range.

http://www.keh.com/shop/product.cfm?bid=CE&cid=07&sid=newused&crid=9613047

[DamienB]

I was initially very happy with my 28-75 - did some very quick test shots, checked centre and corners and was happy. Then did a pile of people & pet shots which looked great... and finally some shots of an aircraft on the ground - this was the first subject that really had the focused area taking up the entire width of the frame, and to my horror I found that the right hand side of the image was distorted/soft. Thankfully found this out before using it for further shots of the aircraft and switched back my 28-135 for the rest of the day.

Further tests find that from f2.8 to about f16 the right hand side is soft (worst at 2.8). So I guess I've got one of the 10% - dammit!

[dsze]

http://photography-on-the.net/forum/showthread.php?t=49000

[DamienB]

Second one turned up... it's once again soft on the right. To add to things, it's also slightly soft on the extreme left edge, while the previous example was not. Back it goes...

[MrChad]

My buddy loves his older Canon 28-70L on his Eos3 and Drebel. What a nice lens IMO.
You get what you pay for, I'd opt for the L, especially if you make a living w/ the lens and need the f2.8L speed and sharpness.

If I could even consider affording it I'd be all over the 24-70L too.
Plus I think 28-70L go for ~$800 used.