Film Nikon FE - is this a problem ?

[phigmov]

I tried searching the web and asking on various forums but I have yet to find out if this issue is something to worry about or not.

My Nikon FE is in pristine condition and I'm very pleased with it, however, I noticed the little steel tab on the body lens mount that indexes the AI tab on the lens only moves in one direction. Comparing it to my FM and F3 I realised that it is meant to be spring loaded and 'ride' the AI tab as the aperture is adjusted.

Looking inside it looks like there is a spring or cord that is meant to provide the suitable tension against the tab and allow it to move with the aperture of the lens. Obviously it does move fine in one direction, it just doesn't return when the aperture is adjusted in the opposite direction.

I was horrified to discover this half-way through a roll of film but all the pictures came out fine.

Is this AI tab return something to worry about ? Is there a technique I can use to compensate for it not moving back (my pinky finger could probably slide it back around with the lens aperture) ?

 

[Lawrence A.]

I don't know anything about Nikons, but if the pictures came out fine, I'd assume the thing is working as it should -- at least when the camera is fired.

 

[Kay]

Depending on how, where and how long the camera has been used some debris might find its way into the slit and the tab gets stuck. Just take out the 4 screws from the lens mount, remove it veeery slowly and use whatever you have (tweezers, toothpicks, ... be careful with q-tips! ) to remove the superflous stuff you find underneath the mount, especially next to the spring. Sounds too simple? That's what I did with my F3 many years ago, which has basically the same mechanism. The whole affair took me 5 minutes and afterwards everything worked just fine again. You could of course have it done by Nikon or a technician but in my case it wasn't a big deal. Don't worry about the registration distance, it does not change.

I tried searching the web and asking on various forums but I have yet to find out if this issue is something to worry about or not.

My Nikon FE is in pristine condition and I'm very pleased with it, however, I noticed the little steel tab on the body lens mount that indexes the AI tab on the lens only moves in one direction. Comparing it to my FM and F3 I realised that it is meant to be spring loaded and 'ride' the AI tab as the aperture is adjusted.

Looking inside it looks like there is a spring or cord that is meant to provide the suitable tension against the tab and allow it to move with the aperture of the lens. Obviously it does move fine in one direction, it just doesn't return when the aperture is adjusted in the opposite direction.

I was horrified to discover this half-way through a roll of film but all the pictures came out fine.

Is this AI tab return something to worry about ? Is there a technique I can use to compensate for it not moving back (my pinky finger could probably slide it back around with the lens aperture) ?

 

[phigmov]

I'll have a look at it next time I get some time.

Does anyone know what the tab actually does ? Does it index the metering 'chip' or stop the lens down when the shot is taken ?

 

[Kay]

I'll have a look at it next time I get some time.

Does anyone know what the tab actually does ? Does it index the metering 'chip' or stop the lens down when the shot is taken ?

It's a part of Nikons Ai (aperture index) system and transmits the difference between open aperture and working aperture to the camera. On the F3 and maybe on the FE too you can flip that thing backwards for older pre-Ai(S) lenses.

 

[trisberg]

I believe the tab is used for the body to know the relative aperture you are using on the lens. If it's off by a step or so you might not notice it but if it is off by several steps you would. It should rest against the AI coupling ridge on the lens and follow along when you change aperture.

 

[trisberg]

On the F3 and maybe on the FE too you can flip that thing backwards for older pre-Ai(S) lenses.

Yes, the FE has that little button you can push to flip the tab out of the way, but you'd have to meter stopped down in manual mode then.

 

[Kay]

Yes, the FE has that little button you can push to flip the tab out of the way, but you'd have to meter stopped down in manual mode then.

Yep, but back in my Nikon days I converted my pre-Ai lenses to Ai on a precision mill.

 

[Dwig]

...

Does anyone know what the tab actually does ? ...

The external "tab" that follows the f/stop ring's mating tab is part of the AI (Automatic Indexing) meter coupling. Its position signals the meter the lens' currently set f/stop relative to the lens' maximum f/stop. Since the meter is "looking" though the lens at its maximum it needs to know the amount the lens will stop down when the exposure is made in order to calculate the correct exposure settings.

If the body's tab is not in contact with the lens' tab the meter reading will be incorrect.

The tab can bind for several reasons:

• It's become dirty or gummy. This usually impacts movement in both directions.
• It's become bent. This is usually caused by attempting to mount a non-AI lens and this usually impacts movement in both directions.
• Its spring has failed. This usually leaves the tap and its ring moving easily but the lens can only push it one way. It doesn't follow the lens' tab back the other direction.

 

[phigmov]

• It's become dirty or gummy. This usually impacts movement in both directions.
• It's become bent. This is usually caused by attempting to mount a non-AI lens and this usually impacts movement in both directions.
• Its spring has failed. This usually leaves the tap and its ring moving easily but the lens can only push it one way. It doesn't follow the lens' tab back the other direction.

Cheers Dwig, I think its the last issue I'm facing - as per Snapdawgs suggestion I'll have a poke around inside. I almost wonder if someone didn't replace the spring with a bit of string as a kludge sometime in the past. I must have just been lucky in terms of setting the aperture tab and keeping it moving forward rather than backwards.