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09-30-2007, 05:39 AM   #1
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Is it me... or the lens... or both ;)

I used my Sears 28mm all day yesterday because we were out exploring Maine and I knew that in addition to cute shots of the kids, I wanted to get the scenery in the background. Got home and was very disappointed to see that almost all the pictures I took were blurry or had funny coloring, and many had vignetting only on the right side.... but not all of them. Why would that only happen sometimes ?

These have been PPd a bit. I used Ben's Action (lol... didn't know you had an action, did you Ben? I turned the steps you recommended into an action to make it quick n' easy) The ones with vignetting all around had the vignetting on the right side only and I added it to the left to salvage them.



I didn't fix it in this one...


Really bummed that this one turned out crappy... I HATE it when I am fooled by a crisp picture on the LCD then get home to crap!


Are some lenses harder to focus than others?? I don't miss this many shots due to focus issues with my 50mm or my kit on MF.

09-30-2007, 05:59 AM   #2
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Humm, Hard to guess why the vignetting. Is there a filter/hood on the front of the lens? Any chance that's causing the issue? As for focus I'd try some test shots at home with a closer, defined subject. The min focus distance is fairly short on a wide angle lens. See what sort of results you get that way. If the lens focuses sharp at say 2-4 feet then you may be having a tougher time with MF focus on a wide lens. It can be harder since the FOV is so much broader and the details are smaller. (what did the focus assist lamp tell you?) Also these lenses have a wide DOF so what settings were you at? Maybe too wide open?

Last thought. Take the lens off the body. Stop it down all the way (f22 whatever). 'flick' the aperture lever a few times while looking through the lens and see if it is opening and most importantly closing down fast and snappy. See if the blades close down uniformly. If the blades stop down slowly so one or 2 seem to 'hang' and the aperture hole is not round, that may cause the issue with focus. Also some lenses are just not able to focus. They have a misaligned element and need adjusting. Hopefully that's not the case.
09-30-2007, 07:00 AM   #3
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No filter or hood and the blades more smoothly when I turn the aperture ring. I just did a little test (because my 'main' job today is to wash the outside of all my windows ...a task I am avoiding as long as possible )

Same 4.5 aperture, same everything...
28mm

kit lens

50mm 1.7


From this I pretty much learned what I already knew... DAMN I LOVE THAT 50mm 1.7
09-30-2007, 07:24 AM   #4
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Well it looks like the lens is soft from that image. But try flicking the aperture lever on the back of the lens, turning the ring won't tell you much. What I'm trying to describe is whether the lens stops down fast and the blades are even and uniform. The aperture will be wide open on the camera body and will stop down to the aperture your set just as the shutter is fired.

It would appear from the picture that the wood table under the remote is reasonably clear but not as good as the 50mm for sure. Try another test when you have time. Take a good quality printed page that is flat on the table (say from a magazine that is well printed). Use a tripod or some other stable support and use the self timer or cable release. Shoot it at an angle and focus on one line of the text (mark the line so you know which one you were trying to get in focus). See if the printed words look crisp and clear. Try a few different apertures. Wide open then f 11, f 16 etc. That may help tell what the lens can do.

10-03-2007, 07:39 AM   #5
JMR
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I am having the same problem and have switched to focusing manually. It's easier than trying to alter the focusing point. I have the 16-45 lens which seems very good and sharp with F4 aperture throughout. But I just bought the 50-200 lens and things appear very soft indeed. I will take 50-200 lens back if this continues. Try focusing manually and see if that makes a difference.

I suspect the cheaper 50-200 lens simply vibrates. But you seem to have a curtain or aperture issue as already noted. Go to a store try a lens, or borrow a lens and see if that makes difference.

JMR
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