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07-01-2010, 03:48 PM   #1
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Tell me if my lens is okay...

Okay, so my first DA* 16-50mm had problems focusing beyond five feet, and also the left side was softer than the left side. I just received the replacement from BH and this one seems worse!! The left side is just as bad as the previous lens, but the right side on this one is much worse than the other lens. Also, the focusing on this one seems worse as well! Anything beyond three feet is completely bad. Almost unusable.

Here are a few photos. The first is shot wide open at f/2.8 50mm auto focus. The second and third are the same image except the first is manual focus and the second is auto focus. It was taken at 2-3 feet away so the AF is much better than if I would have been further away, but it's still not nearly as good as MF, as can be seen.

What do I do? Send this one back and request another one?

07-01-2010, 03:53 PM   #2
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Oops! I'm having trouble uploading the picts... It erred on me and I didn't realize it. I'll have to try to upload them again later.
07-01-2010, 07:23 PM   #3
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Okay, I wasn't able to upload the first image. So here are the two cropped ones. The first being manually focused, the second auto focused.

I got to wondering, I've been shooting exclusively prime for the past several weeks, has that trained my eye to be more "picky," than it would have been before?
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07-01-2010, 07:25 PM   #4
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QuoteOriginally posted by Ubuntu_user Quote
What do I do? Send this one back and request another one?
Short answer based solely on the very small pics you posted: yes.

07-01-2010, 07:29 PM   #5
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I'd try shooting some "regular" subjects first, like a wall or railing at an angle, not 2 dimension printing. You can easily be off a hair and think all is bad. Shoot something so you can see the focus point regardless of if it is front or behind where you thought it would be. (That is a separate issue).
07-01-2010, 07:33 PM   #6
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You might want to try it in normal environments before judging it useless, also can you put anything else from the state of the pictures? Aperture, etc. and what camera are you using for it might help also.

Be aware that it could also be a problem with your camera mount (improbable), back/front focus or just a bad lens.

Please take some pictures outside in better lightning and post again.
EDIT: you might want to resize them before posting them here. Normally 1200x800 or less is good, 900x600 might be better.
07-01-2010, 07:44 PM   #7
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How to diagnose faulty camera equipment.
07-02-2010, 07:48 AM   #8
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Here are a couple real life photos. I was standing about 20 feet away from subject. First is AF, second is MF. Now you tell me if there's not something wrong with that?! These were both shot at f/2.8

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07-02-2010, 08:55 AM   #9
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QuoteOriginally posted by Ubuntu_user Quote
Here are a couple real life photos. I was standing about 20 feet away from subject. First is AF, second is MF. Now you tell me if there's not something wrong with that?! These were both shot at f/2.8
There's something wrong with that. You don't need to get testy. If you are telling, not asking, why bother?
07-02-2010, 09:01 AM   #10
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Your mf looks more focused on the flowers. What camera?, can you tweak the fine focus adjustment maybe?.
07-02-2010, 11:00 AM   #11
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QuoteOriginally posted by SpecialK Quote
There's something wrong with that. You don't need to get testy. If you are telling, not asking, why bother?
Oops! Didn't mean to come across as though I'm not asking advice. I most definitely want your opinion...

QuoteOriginally posted by Ex Finn. Quote
Your mf looks more focused on the flowers. What camera?, can you tweak the fine focus adjustment maybe?.
Exactly. I focused on the flowers, but the AF focused on space. I've tried the focus adjustment, but had no luck. Oh, btw it's on the K7.
07-02-2010, 11:43 AM   #12
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That's a crazy kind of a shot to try to get right in the first place:

A potted plant on the ground with a ton of foreground and background grass it's sitting on?

It's simply not a composition to use as an example. Your AF could have locked onto ANYTHING. It doesn't mean that the lens is bad.
07-02-2010, 12:51 PM   #13
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There's a reason people invented focus test charts and controlled testing methods. Those will quickly resolve questions that "real world" examples only confuse.

But FWIW, if you have a focus problem, there's no obvious reaosn at this point to suspect the lens rather than the camera.
07-02-2010, 03:11 PM   #14
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There is no EXIF attached, you did use center point af, correct?.
Open the image with PhotoMe and see where the focus locked. Even the center point is not that tight as far as the actual spot size is concerned.
07-02-2010, 03:14 PM   #15
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QuoteOriginally posted by Ex Finn. Quote
There is no EXIF attached, you did use center point af, correct?.
Open the image with PhotoMe and see where the focus locked. Even the center point is not that tight as far as the actual spot size is concerned.
yes, center point af.
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