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Old Mar 27, 2006, 9:32 PM   #1
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I know that most of the well respected on-line sellers will take a lens back if it's obviously defective, but what it it's just not tack sharp - close but not there. For instance, will B&H or Adorama take back such a lens. I have been reading reviews, asking questions, and looking at posted photos for the lenses I'm interested in, and, as you can imagine, there is a wide variation in quality of photos posted on different sites. All the lenses I'm looking at seem to be able to produce very sharp images for some people some of the time. My Sigma 150 macro can give great results, and the 24-70 gives acceptable results, but not great most of the time. If I'm just not happy with the Sigma 80-400 for instance, is it easlily returnable for another copy - how about for a different lens? The photo below is what I'd like to get - it's from the Canon 600L I got to try last Friday. But at that price, I'd expect that kind of sharpness.



Thanx,
Ron
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Old Mar 28, 2006, 8:25 AM   #2
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Doubt if anyone would change it if its not defective. Look at DP CHALLenge users remarks on lens. Some excellent, some good and some poor. You pays your money and you takes your chance.
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Old Mar 28, 2006, 11:16 AM   #3
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I've read here that some folks with Nikon and Canon lenses were able to send it back to them for tweaking, assuming it's still on warranty. But I think you have to prove to them that it doesn't focus right, either back focusing or front focusing.

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Old Mar 28, 2006, 2:01 PM   #4
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Can`t think what you could tweak as it is all screwed up tight.
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Old Mar 31, 2006, 4:18 PM   #5
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How do you judge your lens is 'not sharp'? Really the only way is to take a series of controlled test shots on a tripod. Make sure there is sufficient light for the auto focus to work correctly. Canon publishes a standard test setup they use for this kind of testing.

Sharpness is a combination of factors. The lens, the camera's autofocus, you (!) holding the combo still while pressing the shutter, available light, the subject you take (it might move), etc.

Canon's DSLRs do not apply much sharpening in camera. They leave it to the user to do that during post-processing.

I went through the whole 'does my setup focus correctly' testing once. I took pictures of a test pattern at a 45 degree angle on a tripod, at various distances and apertures under good light. I thought I found a few back and focus issues, and sent my whole setup (body plus lenses) back to Canon. they calibrated it all and it came back a bit better. Would I have ever noticed in real use? Probably not.

Barthold


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Old Jun 18, 2006, 9:46 PM   #6
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Barthold

You mention that "Canon publishes a standard test setup they use for this kind of testing" Could you describe how to get access to this test?

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Old Jun 21, 2006, 11:36 PM   #7
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surfnron wrote:
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I know that most of the well respected on-line sellers will take a lens back if it's obviously defective, but what it it's just not tack sharp - close but not there. For instance, will B&H or Adorama take back such a lens. I have been reading reviews, asking questions, and looking at posted photos for the lenses I'm interested in, and, as you can imagine, there is a wide variation in quality of photos posted on different sites. All the lenses I'm looking at seem to be able to produce very sharp images for some people some of the time. My Sigma 150 macro can give great results, and the 24-70 gives acceptable results, but not great most of the time. If I'm just not happy with the Sigma 80-400 for instance, is it easlily returnable for another copy - how about for a different lens? The photo below is what I'd like to get - it's from the Canon 600L I got to try last Friday. But at that price, I'd expect that kind of sharpness.



Thanx,
Ron
First off, Ron, you're setting yourself up for disappointment by comparing your 3rd party consumer zooms against a Canon L prime lens. These lenses are the holy grail of sharpness.

But to answer your question, I've sent a couple lenses to Canon for recalibration, and they returned sharper both times. These were used lenses though, and Canon charged me about $100 per... I have returned new lenses to B&H for a refund as well, but not because I was disappointed with sharpness.

Regarding judging other's copies by their posts, you must remember that much more goes into making a technically correct photograph than the lens used. Proper technique to get a sharp photograph takes skill as well. Finally, there are two things you must remember: 1) You get what you pay for. You want professional image quality, you may have to spend professional cash. There are exceptions to this rule of course, but it's usually true... And 2) Sharp does not a good photograph make. If you're photographing catalog jewelry or something like that, then go ahead and antagonize over ultimate sharpness. But for most photographs, and standard print sizes, it doesn't need to be tack sharp to be a great photograph. This is especially true when photogrpaphing people. If you don't believe me, just go look at some Natinal Geographic magazines. Best, softest photos in the world. It's you that makes a great image, not your lens.

I hope this helps,

Chris M
www.imagineimagery.com

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