View Full Version : Off-center aperture
Jay M. Packer
28-Jul-2011, 23:03
I recently purchased a used 75mm f4.5 Nikkor lens on a famous auction site. The glass is in fine condition, but the aperture diaphragm, although round enough, is about a millimeter off-center. When the aperture is opened, a 1mm crescent of visible blade remains around half of the periphery.
What is the optical effect, if any, of a slightly off-axis aperture? Should I return the lens, or just blithely use it to make my usual bad photographs?
-- Jay
How many aperture blades in the shutter?
How many of them are not opening fully?
- Leigh
Jay M. Packer
29-Jul-2011, 06:09
How many aperture blades in the shutter?
How many of them are not opening fully?
- Leigh
It's a standard seven blade Copal 0 shutter. All the blades open fully, but the entire aperture assembly is not centered on the optical axis of the lens.
ic-racer
29-Jul-2011, 06:55
How many aperture blades in the shutter?
How many of them are not opening fully?
- Leigh
Agree, one or two may have jumped the pins. Putting in a too-long index screw can touch the blades and cause one to jump out of place.
Jim Galli
29-Jul-2011, 07:27
Jay, there are certain lenses, antiques like Verito etc. that I would have a wide tolerance for that condition and others like a modern wide angle where I would have zero. I'd return it.
Jay M. Packer
29-Jul-2011, 07:52
Gentlemen, thank you very much.
-- Jay
I just realized I have that exact same lens (Nikkor-SW).
Upon examination I find that the aperture blades are absolutely uniform from full open to minimum.
- Leigh
Jay M. Packer
29-Jul-2011, 13:38
I just realized I have that exact same lens (Nikkor-SW).
Upon examination I find that the aperture blades are absolutely uniform from full open to minimum.
- Leigh
Thanks, Leigh; that's helpful information.
-- Jay
Armin Seeholzer
29-Jul-2011, 15:14
Same on mine just as it should be, and Jim has absolutly right on this one as almost ever!
Cheers Armin
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