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10-26-2012, 06:39 AM   #1
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FA28-70mm lens flawed?

I picked up a superb condition FA28-70mm f4 last week, and was just trying it out today. There seems to be an issue in that at wider FLs, there is a bleary unclear portion of the image. Not off to one side, or in the corners, like you commonly see, but just below the middle of the shot. Where the telephone cables cross the road in the image below. There does not seem to be anything inside the lens that is causing this - everything looks crystal clear in there.

I have tried several times, adjusting focus, with similar results.

This is only a cheap lens, and I can probably send it back, but I just wondered whether the forum members could shed any light on this.

10-26-2012, 06:51 AM   #2
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The FA28-70 is known for being prone to element separation in the rear group. I had one like that myself but in my case the whole frame was very soft at all apertures.
Check if you see some white fog or haze when you look through the lens wide open with a light. It should be very easy to see if that causes the problem.
Try another sample, apart from that issue it's a fine little lens!
10-26-2012, 10:26 AM   #3
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Do you use a lens hood or do you use a protective filter? If the issue isn't the above mentioned element separation, I would suspect a flare issue. Flare can best be avoided by using an appropriate lens hood and (with or without a hood) avoiding the use of any extra optical surfaces in front of the lens.
10-26-2012, 10:35 AM   #4
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It looks like it could possibly be a spot of condensation on the centre of one of the convex lenses. If that was the case, I would expect it to dissapear within a few hours. Otherwise I would say the lens is faulty and I would ask for an exchange unit if possable.

10-26-2012, 03:26 PM   #5
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Original Poster
Thanks for the responses. No filter (or hood) was used, but I will take more shots and see if it improves.

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