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12-06-2006, 04:24 AM   #1
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Oh no, front focus again.

Sorry about this folks but could you give me your opinions.

This is my 50-200 DA and I think it looks about right.

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This is my 16-45 DA and I'm not so sure about this one.

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Finally the same lens focused on the middle barcode.

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Should I return this lens?

12-06-2006, 12:49 PM   #2
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My 16-45mm certainly is focusing like your 50-200mm and I think they are right. My DS focuses more to the rear but still gives me tack sharp shots.

What settings are you using?
12-06-2006, 01:12 PM   #3
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Is the last image (barcodes) cropped? If so, could you provide full version -- reduced size is OK (640x480 or so). I would like to see relative area under the central focus point to the rest of the image. That could be important.

Your 50-200 and 16-45 samples are not taken from the same angle. 16-45 looks more angled thus making anything that is out of focus due to limited DOF more visible. I would say be very careful when comparing these two!

But to me they both look good and I don't see any reason for returning the lens: AF systems are susceptible to errors and their precision is just an approximation. Performing the test with that test chart may not be the best way to check your camera. Better yet, try auto focusing and manually focusing on several real world subjects and compare results. If they look identical no reasons to worry. If they are different in all cases and for all/most lenses then your camera may need to be adjusted.
12-06-2006, 04:27 PM   #4
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The 2nd image has definite FF.

I went through 2 K10 bodies. The first would FF badly with the 77ltd and not so bad with the Sigma 24-70EX.

The second body would focus perfectly with the 77 and Sigma when 5 or 6 feet or closer.

Both would FF badly the further away from the target the worse it was.

I doubt that I had 2 bad lenses.

So I kinid of gave up on Pentax at this time

12-06-2006, 05:22 PM   #5
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Original Poster
QuoteOriginally posted by peted Quote
My 16-45mm certainly is focusing like your 50-200mm and I think they are right. My DS focuses more to the rear but still gives me tack sharp shots.

What settings are you using?
Shots were taken with lens wide open, using the center focus point. All were taken using the on-board flash in ĎPí mode.

QuoteOriginally posted by i.glisin Quote
Is the last image (barcodes) cropped? If so, could you provide full version -- reduced size is OK (640x480 or so). I would like to see relative area under the central focus point to the rest of the image. That could be important.
It is a crop. Iíll post the original later. The central focus point marker was all well within the boundaries of the middle barcode.

QuoteOriginally posted by i.glisin Quote
Your 50-200 and 16-45 samples are not taken from the same angle. 16-45 looks more angled thus making anything that is out of focus due to limited DOF more visible. I would say be very careful when comparing these two!
The difference in angle is at least partly due to the difference in field of view. I wanted to avoid the extremes of the zoom range with both lenses so the camera was significantly further away for the 50-200 shot. That said, all shots were handheld so differences in angle are likely and I take your point.

QuoteOriginally posted by i.glisin Quote
But to me they both look good and I don't see any reason for returning the lens: AF systems are susceptible to errors and their precision is just an approximation. Performing the test with that test chart may not be the best way to check your camera. Better yet, try auto focusing and manually focusing on several real world subjects and compare results. If they look identical no reasons to worry. If they are different in all cases and for all/most lenses then your camera may need to be adjusted.
Okay this is what I was hoping to hear. My feeling at the moment is that if there is a problem it might one I can live with. I will go out shooting this weekend and really try to pin this down.

QuoteOriginally posted by iL Medico Quote
The 2nd image has definite FF.

I went through 2 K10 bodies. The first would FF badly with the 77ltd and not so bad with the Sigma 24-70EX.

The second body would focus perfectly with the 77 and Sigma when 5 or 6 feet or closer.

Both would FF badly the further away from the target the worse it was.

I doubt that I had 2 bad lenses.

So I kind of gave up on Pentax at this time
Thanks for your input. I am sorry to hear about your experiences. I will shoot at longer distances this weekend and see how that affects things.

At this time I love the K10 too much to give up on it yet. Iíll work at it and see how thing pan out.
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