An F3HP issue, or a lens issue?

[LeftCoastKid]

I have a question for my fellow F3HP shooters, perhaps related to the camera's coupling, and/or the flange on my 80-200 F4 Ais lens. To wit: As expected, my entire assortment of Ai/Ais Nikkor lenses (15mm-600mm) work without issue on my F3HP body. The exception: my 80-200 F4 Nikkor. The lens will work properly when it's the first lens mounted on the camera for a particular outing. Changing to a different lens (or through several lens changes), and then returning to the 80-200, results in a constant underexposure reading on the camera's meter, irrespective of the shutter speed or aperture chosen. Returning to any other lens, the problem doesn't show.
I've checked the 80-200 lens on six F2 bodies, as well as on my F3P, 2 F5s and my F6; the lens performs without issue.
The coupling on the F3HP moves the same with all lenses, and the flange on the 80-200 moves as expected; I see no sticking or hesitation anywhere. Any ideas as why this particular lens, only on this one camera should behave like this?

 

[shutterfinger]

I only have a F4s and a pair of D Nikons but this sounds like a lens problem.
Operate the aperture lever that couples with the body on the lens and compare it to your other lens. The lever must remain perpendicular to the mount throughout the range. The pressure required to move the lever should be the same throughout the range and be the same as the other lens. Inspect the lever in the body, it should be parallel to the mount and move with the same pressure throughout its range. .001 inch and .5 grams can be the make/break points.

 

[voceumana]

If it works the 1st time it is mounted, have you tried recycling the power switch to see if that restores normal operation?

 

[LeftCoastKid]

Thanks for both your relies. Couplings/lens mount were the first things to come to mind; both worked as they should. Powering on/off didn't change the glitch. Very strange that tis problem only arises on this one particular camera, and only after I've changed lenses,,,

 

[reddesert]

The camera doesn't know anything about what lens is mounted beyond the aperture coupling ring position and the amount of light coming through it. (I believe an F3 doesn't sense the AI-S indicator cutout, but I don't have one to check.)

Something is not moving freely - either the aperture ring isn't engaging the flip up tab on the camera ring, or the camera ring is binding, or the lens aperture is stuck at a small value (which I think you would have noticed by looking through it).

 

[John Koehrer]

GREMLIN(s)

 

[mawz]

I'd suspect the issue is in the aperture linkage, not the AI coupling

 

[Chan Tran]

I think something is wrong with the lens aperture coupling.

 

[Chan Tran]

I'd suspect the issue is in the aperture linkage, not the AI coupling

The OP should be able to check it but I suspect that the AI coupling stuck at maximum aperture and doesn't follow the aperture ring when the lens is stopped down thus underexposure. If the aperture blades are sticking you would have over exposure because the the camera thinks the lens will stop down but it doesn't due to the sticking blades.

 

[bdial]

Are you using any other f/4 lenses?
What happens if you test by using stop-down metering with the various lenses?

 

[LeftCoastKid]

Thanks for all the suggestions. Mr Chan Tran called it: aperture coupling is sticking, but only intermittently - perhaps why I failed to see it? Any suggestions on a possible remedy?

 

[John Koehrer]

could be dust or grit between the ring and body. It don't take much.

 

[LeftCoastKid]

could be dust or grit between the ring and body. It don't take much.

Thanks for the suggestion. Did a close inspection and a clean up with isopropyl alcohol. Same pattern: works for a bit, but seems to stick at random intervals.

 

[mpirie]

It sounds like you may need to add a lube of sorts and not just IPA which can remove old lube.

It might be worth trying an electrical switch cleaner spray if you can't take the ring off for cleaning.

Mike