Nikon FA Metering Issues

[arnold_schmidt]

I recently acquired a Nikon FA and a 50mm F/2 AI lens to use on it; I was under

the impression that when coupled with an FA an AI lens would offer full

functionality in all shooting modes. It didn't come with batteries so those

installed a brand new, so a diagnosis related to low battery issues are

probably invalid. However my FA is confusing me due to the inconsistent meter

readings it is giving in aperture priority mode.

 

The camera always meters as if the 50mm lens is stopped down to its lowest

aperture (F/16) and doesn't not seem to respond to any changes in aperture that

I make on the lens. For example when metering under partial cloud and with the

diaphragm set to F/4 the FA will indicate a shutter speed in the region of 1/8

seconds, a reading sensible for F/16 but not F/4. Regardless of what is says on

LCD the FA shutter speed used for shooting seems fine, i.e. it shoots correct

speed not the improperly slow one.

 

Interestingly the camera seems to produce accurate readings if the DOF preview

lever is depressed thereby stopping the aperture down to the value set.

 

The FA seems to work fine in S mode (the LCD indicates sensible aperture values

to match the shutter speed I provide), can anyone here shed some light on the

problem I'm experiencing. Thank you.

[Jerry_]

Aside from 'old' age, your camera may be in need of a CLA (Clean-Lube-Adjust,) but if any parts are needed for the light-meter system, good luck. Twenty to 25 years have gone past since the FA was manufactured....a good camera it was, it might be not-so-good to repair.

[arnold_schmidt]

Thanks for the reply, I have only just bought the camera and the seller described it as being in 'excellent working order'. If as you say it is seriously flawed then I imagine I'm within my rights to return it.

[neil_parker]

Robert, you need an AIS lens to use all the metering modes in an FA. The AI lens should

meter and work properly in manual and 'A' - aperture-priority. It will not work properly in

program mode or 'S' -shutter-priority. There is no way for the body to control the aperture

in an AI lens.

[arnold_schmidt]

Neil. I realise this, however I am mainly worried about the problems I'm experienced with an AI lens when working in 'A' mode. Even when I manually adjust the apeture on the lens the LCD meter reading does not change. Additionally I have tried a modern AFD lens, which I gather is also in some respects an AIS lens and it has the same fault.

[neil_parker]

You're right, the AFD should function like an AIS on the FA. And you are having the

problem with more than one lens? So maybe there is something wrong with the body, the

Auto-indexing meter coupling with the aperture ring would be something to check, you've

ruled out the batteries, but even new ones are occasionally bad, here is what the MIR site

says about battery check on the FA:

 

"With sufficient battery power, the LCD stays on for 16 sec after you take your finger off

the button. If the batteries are weak, the LCD will turn off immediately when you take your

finger off the button."

 

It sounds like you have tested this with film and are getting good results regardless of

what the meter is telling you?

[arnold_schmidt]

I have tried the only two lenses I own which work on the FA, both perform the same way. The camera passed the MIR battery check. I haven't shot any film yet however when stopped down correctly the meter readings agree with that of my accurate Nikon D50.

[jkmccarthy]

<p>This may or may not help, but have you tried switching between "matrix metering" and "center-weighted metering" using the pushbutton switch on the front lower right side (from behind, i.e., from the viewfinder eyepiece -- front lower left if you're looking at the camera from the front) ? See Figure 1 here:</p>

<p>

<a href="http://www.mir.com.my/rb/photography/hardwares/classics/nikonfa/operation/basic5.htm">http://www.mir.com.my/rb/photography/hardwares/classics/nikonfa/operation/basic5.htm</a>

</p>

<p>Try the switch in both positions and report results to the seller before you return the camera body.</p>

<p>--Jim</p>

[arnold_schmidt]

Thanks for the response Jim. This makes no difference. The only way I can get a valid exposure reading for the apeture I select in A mode is by using stop down metering via the DoF preview button.

[anthony_velazquez]

Nikkor AI and Nikkor AI-s lenses that are shorter than 135mm work exactly the same on the FA in ALL metering modes including Shutter Priority. AI-s Lenses that are 135mm and longer activate a "High Speed" program shift and that is the only difference. AI Lenses 135mm and longer still work in all metering modes including shutter priority minus the program shift which you can account for manually<div></div>

[arnold_schmidt]

Thanks Anthony, you've confirmed my theory that all of the lenses that I have tried should be working on the FA. It seems to be the camera which is at fault, it looks like I will be getting a refund or replacement from the seller. Thanks again for the info.

[jkmccarthy]

<p>... So it doesn't sound like the "matrix metering" logic is at fault, but rather the AI (automatic indexing) coupling ring (or circuitry behind it) that's supposed to tell the meter how much the lens aperture is stopped down (even though aperture remains wide open for brightest view in viewfinder). If the camera body was a Nikkormat FT3 or FM or FE (to name just a few), my suggestion would be to check whether the metal AI coupling flap was in the down (engaged) or up (disengaged - for non-AI lens) position:</p>

 

<p>

<a href="http://www.mir.com.my/rb/photography/hardwares/classics/nikkormat/fseries/ft3/lenscoupling.htm">Nikon FT3 lens coupling</a> (see "Coupling Lever Release" in bottom photo)

</p>

 

<p>...but sadly on the FA the AI coupling flap is black plastic and fixed in the down position. So next question I suppose is whether this black plastic flap on your Nikon FA might be broken off ? (Had a previous owner tried to force a non-AI lens onto the body, it's possible the AI coupling flap could be broken.) Here's another FT3 reference photo that shows the coupling lever in chrome against a black body (just above "t" in Nikkormat in this photo), showing how far forward the coupling flap is supposed to extend:</p>

 

<p>

<a href="http://www.mir.com.my/rb/photography/hardwares/classics/nikkormat/fseries/ft3/khokingFT3/nikkormat_ft3_04.JPG">Nikkormat FT3 top front view</a></p>

 

<p>But if the coupling flap is intact, then the problem must be internal ... sorry.</p>

 

<p>The Nikon FA is a wonderful and feature-rich camera, so if you do end up returning this one to the seller, I hope you find another one and get to enjoy using it !</p>

 

<p>--Jim</p>

[jkmccarthy]

Here's another reference photo (this one an FE2 -- similar to the FA in having fixed black plastic AI coupling flap) that gives one an idea how far outward this flap should extend, unless broken off or otherwise damaged.<div></div>

[arnold_schmidt]

The flap seems to be ok, it will freely move around the lens mount (allthough it is a little loose). Can you confirm what I'm actually supposed to be looking for, I don't really follow your logic- sorry.

[jkmccarthy]

<p>Sorry I wasn't clearer before. I realized after posting the FE2 picture in-line above that neither feature "1" nor "2" called out in red were the meter coupling flap I was talking about. Sounds like this wasn't what confused you, but for others' future reference, I'm reposting that picture below with the piece in question circled in yellow.</p>

 

<p>Basically, my speculation was that the protruding black plastic piece on the camera body was no longer protruding, and hence the rotating the aperture ring on the AI lens was not engaging this piece (and your lens aperture setting wasn't being communicated to the camera body). But if the black plastic piece protrudes far enough to be "pushed around" when the aperture ring on the lens is rotated, then my speculation about your Nikon FA metering problem is wrong.</p>

 

<p>Your reply does prompt another question, however. The ring to which this protruding piece is attached should also be "spring loaded" making it want to go clockwise (as viewed from the front, with the lens removed, like in the picture below). Maybe I'm reading too much into your comment that "it will freely move" and/or "it is a little loose". But, if the ring isn't spring loaded, then here again, your lens aperture setting won't be sensed by the camera body since this relies on the black plastic "meter coupling" flap tracking the AI coupling ridge on the rear of the lens.</p>

 

<p>Again, my speculations could be (probably are) wrong when it comes to the root cause of your metering problem. If the flap is intact and the ring it protrudes from is spring-loaded, that ring will be rotated (as it's supposed to be) when you set the aperture on your AI lens. What happens next inside the camera body (e.g., gear train and electronic circuitry) is unexplored territory for me, so I can't be of any further help, provided the exterior mechanical parts seem to be okay.</p>

 

<p>Anyway, best wishes on your refund and finding another.</p>

 

<p>--Jim</p><div></div>

[arnold_schmidt]

I think you may have cracked it! You say the part is supposed to be spring loaded and it should 'want' to rotate clockwise as viewed, the spring on my FA seems to have failed I can rotate the plastic flap however I please with no resistance at all.

 

This fits with your theory and explains why the metering doesn't seem to work.

[jkmccarthy]

<p>Very interesting! Yes, the ring should "want" to move clockwise as viewed from the front, and (without a lens in place) the "flap" (or "tab" ?) should come to rest in approximately the position circled in yellow above. Installing an AI lens (which you rotate counter-clockwise to install in the bayonet mount, of course) should push the protruding tab counter-clockise some distance. With the lens in place, the more "open" the lens aperture, the farther clockwise (back towards the no-lens position) the meter coupling tab should move. Conversely, the more "stopped down" the lens aperture, the farther counter-clockwise the auto-indexing (AI) feature on the lens should push the meter coupling flap on the camera body.</p>

 

<p>You reported yesterday that with lens attached and the Nikon FA in Aperture Priority mode (and lens wide open), the meter behaved like the lens was stopped down to its minimum aperture. That implies the meter coupling flap was out-of-position somewhere too far counter-clockwise. With lens wide open, if you can rotate the Nikon FA's black plastic meter coupling ring (to which the flap is attached) by hand -- perhaps with a finger against it at the bottom -- try rotating the ring clockwise (as viewed from the front) until stops. Does this now result in believable shutter speeds in Aperture Priority mode ? And if, with light finger pressure on that ring to mimic "spring loaded" tension, you then stop down the lens, does the meter respond accordingly ?</p>

 

<p>If everything seems OK except for that ring not being spring-loaded and you are otherwise very pleased(?) with the Nikon FA's condition and price, maybe you'd rather call a local camera repair shop (or Nikon-USA) and inquire as to the cost of replacing the internal spring (a "minor" repair, as repairs go??), then talk to the seller to see what sort of deal they might be willing to work out ?</p>

 

<p>Best of luck,</p>

 

<p>--Jim</p>

[arnold_schmidt]

Thanks for the confirmation Jim. I have moved the flap around manually and the meter operates as expected. The seller has offered me a refund which I may take, however I'd to first investigate repair options as getting a spring mechcanism won't be major work to undertake and I think I got a fairly good deal on the camera anyway.