Off-center aperture

[Jay M. Packer]

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

[Leigh]

How many aperture blades in the shutter?

How many of them are not opening fully?

- Leigh

[Jay M. Packer]

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]

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]

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]

Gentlemen, thank you very much.

-- Jay

[Leigh]

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]

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]

Same on mine just as it should be, and Jim has absolutly right on this one as almost ever!

Cheers Armin