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02-10-2015, 06:23 PM   #1
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De-Centered Lens

I just received a 67 55-100 lens. I also just bought a Zeiss test chart to double-check all my lenses. When I set up the 55-100, focus on the centre circle, then start to throw the lens out of focus, the centre circle begins to separate and turns into 4 distinct circles at the extremes of the focus throw. I think I know the answer but want to confirm that this is an indicator of a de-centered lens. If so, does anyone have an idea of what it would cost to correct? My first instinct is to return it, but I got a good deal on it and I might be willing to negotiate with the seller if it can be fixed.
Thanks

02-10-2015, 07:47 PM   #2
osv
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maybe post some pics of the issue.

i usually think of decentering as being softer on one side than the other.
02-10-2015, 09:01 PM   #3
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LensRentals.com - Testing for a Decentered Lens: an Old Technique Gets a Makeover

Maybe try the methods on this site before you go any further.
02-10-2015, 09:19 PM - 1 Like   #4
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OK, don't I feel like a numnuts. The reason the image is splitting when out of focus is because I have it dead center of the focusing screen (it's doing what it's supposed to do). When I move the center of the test chart outside the center of the focusing screen and check, everything is fine. Guess I can keep the lens after all. Gotta get used to focusing screens again.

---------- Post added 02-11-15 at 02:22 PM ----------

QuoteOriginally posted by UncleVanya Quote
LensRentals.com - Testing for a Decentered Lens: an Old Technique Gets a Makeover

Maybe try the methods on this site before you go any further.
Yeah, reading that is what made me buy the Siemens chart I'm using. Just wasn't thinking the test thru. Turns out the lens looks fine, but thanks.

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