Dumb Nikon rookie error - pre-AI lens stuck on FM2N

[510Oakster]

Yesterday I took possession of my first Nikon FM2N body, went home and figured I'd take the lens off my also-new-to-me Nikkormat FTN and mount it on the FM2N to have a look-see. I got the lens on fine, but didn't realize or think that the coupling mechanism is different, and can't figure out how to get the lens off without the indexing prong on the lens breaking the indexing tab on the camera body.

I thought I may be able to remove the indexing prong, but don't see how I could fit a screwdriver past the projection of the pentaprism, below the Nikon nameplate.

Am I good and truly screwed here...please tell me there is a simple solution to my foolishness.

 

[Nicholas Lindan]

I don't know if you can do it or not, but try removing the screws that holds the bunny ears in place.

 

[BrianShaw]

My 40 year old recollection is very vague but isn’t the indexing arm on the body spring loaded?

 

[madNbad]

Set the lens to the minimum aperture and try again.

 

[510Oakster]

I don't know if you can do it or not, but try removing the screws that holds the bunny ears in place.

Yes, that’s what I was hoping I could do, Nicholas. I called it the indexing prong, but bunny ears is more descriptive. But I won’t be able to get a screwdriver past the prism housing to the screws.

 

[Donald Qualls]

Set the aperture to the widest you can, the bunny ears should move over enough to get the screwdriver past the prism housing.

 

[510Oakster]

My 40 year old recollection is very vague but isn’t the indexing arm on the body spring loaded?

Sadly, no it’s not. I found a picture on the web, and apparently some early indexing arms were spring loaded, but the FM2N is new enough that that part is solid plastic.

 

[BrianShaw]

Sadly, no it’s not.

Thanks for that confirmation. I’ll delete that faulty recollection from my cranium!

 

[510Oakster]

Set the aperture to the widest you can, the bunny ears should move over enough to get the screwdriver past the prism housing.

BINGO! Thanks for the encouragement - getting the screwdriver past the prism housing looked impossible, until I actually tried it! Fortunately the screws weren’t frozen, and they unscrewed easily. I noticed that the screws were already a bit nicked up - perhaps a prior owner made the same mistake? So now, on to cleaning and shooting...

 

[Donald Qualls]

Hurrah!

 

[BradS]

Hopefully it did not damage the FM2N. The problem is that pre-AI lenses that have not been AI'd do not have a recess into which the the little AI tab that sticks out from the lens mount flange on the FM2N would normally fit. The first FE and FM bodies allowed the little AI tab to be flipped back out of the way - enabling non-AI lenses to be safely mounted. Later FM2, FM2N, FE2, and FM3A lack this feature and so mounting a non-AI lens on any of these typically damages the little AI tab on the body. Good rule of thumb...never force stuff.

 

[510Oakster]

Good rule of thumb...never force stuff.

Yes! I learned the hard way repairing vintage sewing machines and typewriters...never use violence! Thanks for the info, I was terrified of breaking that plastic tab - I’m sure that repair would have cost more than I paid for the camera.

 

[MartinCrabtree]

The FM2n is worth the money to repair.