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Old Sep 21, 2004, 11:21 PM   #1
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Can anybody offer some insight as to what may be wrong with my 28-105 lens? It seems that recently photos--notably portrait shots of people--tend to be unusually soft, especially in the center of the shot. Some shots do seem to turn out okay, including distance shots of people/objects at 105mm. I've checked both ends of the lens for smudges or scratches but can find nothing obvious.

I was beginning to think it was a lack of skills or technique on my part, though in the past (I've owned my Canon Digital Rebel for three months now, and the 28-105 for two) there's been no problem...Well, the other day after shooting several portrait shots I switched back to the kit lens to take some more pics, and when I looked at them later on my computer the softness was there on the 28-105 pics while the kit lens pics were (gulp) perfect! :shock:

Any ideas?
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Old Sep 21, 2004, 11:30 PM   #2
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Hum hard to guess what is wrong, I had a Sigma 28-105 that had the diaphram fail and all images were taken at f2.8 for a while, that can make for some fuzzy lack of DOF.

Also if you are in a humid location, check your back element again, and if you can try to look at the internal ones. Fungus does like to grow on and eat into the elements. BUT this is not normal unless you are in a realhumid location.It is also not so easy to clean.

Also if you can find someone who has a Canon, try the lense on their camera to see if the problem occurs there too, might be a communication problem between your camera and the lense (maybe bad contacts?)





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Old Sep 22, 2004, 1:04 AM   #3
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Okay, well I did some test shots just now, comparing both the 28-105 and the kit lens to make sure it's not a "user" issue, and in each case the kit lens performed as it should, with sharp, crisp images taken at any setting. With the 28-105 I found that anything with an apeture set wider than 8 began to soften, moreso than the kit lens. Anything smaller than 8, all the way to 25 was just fine. Again, the kit lens performed well in the same shots at the wider apetures, so I can be confident in saying it isn't me not getting it right.
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Old Sep 27, 2004, 11:20 AM   #4
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> Can you provide some samples? With intact EXIF if possible.


Here is a link to my Yahoo Photos with the two pics: http://photos.yahoo.com/briantium2.

IMG_5236 is the "problem" pic. Both pics are 100 ISO, and both are cropped to 100%. The "bad" pic is set at 35mm, F4, shutter speed 1/2000. The "good" pic, IMG_5238, is F8, 1/500, also at 35 mm. Taken within seconds at Apeture Priority. This has been consistent throughout countless pics, regardless of settings (manual, shutter priority, portrait, etc). All pics come to the same thing at any photo lower than 4.5. I did not have this problem before a couple weeks ago and I do not have this problem on the kit lens. As you can see the F8 shot is great and on my other test shots was great as well.
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