Nikkormat FT Light Meter Faulty?

[callie]

Hey There,

So I got a Nikkormat FT a few days ago but I think the light meter may be faulty,

I downloaded a few iPhone app to try and prove that the light meter is off.

Check the attached pics

With the camera set to 800 iso film and 2.8f is saying I should shoot at 1/60... when the apps all say over 1/1000 ???

 

[jimjm]

Callie -

It's possible the meter is off, but a few things to verify first:
- Fresh battery of correct voltage? I believe the FT originally took 1.3v mercury batteries, so your options these days are a Wein cell or CRIS MR-9 battery adapter with 1.5v silver battery
- Battery compartment clean with no corrosion?
- Are you indexing the lens after mounting it? Turning the aperture ring fully back & forth once to min and max apertures indexes the meter for the speed of the lens.
- This looks like a non-Nikkor lens you have mounted. Do you have a Nikon lens you can try this with?
- Hard to tell from your shots, but were these taken outdoors or inside? Hard to know what meter reading you should be getting, and if your App is correct.
- Are the focusing screen and mirror relatively clean and unobstructed? The metering cells are in the prism on either side of the eyepiece, and read the light off the image on the screen.
Try setting to a lower ISO like 100 and go outside on a sunny day. Metering off an open area like grass should get you close to Sunny-16, which would be about 1/125 @ f16, or 1/250 @ f11, 1/500 @ F8, etc.
I agree that this is a big discrepancy between your readings, so it's possible the meter is faulty. Luckily the FT is still a great camera to shoot with, even with a non-working meter.

 

[jimjm]

If I recall correctly, the back-and-forth indexing does not apply on the FT. I believe the FTN was the first Nikkormat that did this. With that done correctly, sounds like it could be a CdS cell failure.

Right you are...
I have the FTn, which had this "auto-indexing" feature. The FT has a separate setting to indicate max lens aperture.

 

[ronnies]

The photos are of an FTn though so the indexing does apply. Check the red line on the left of the mount is lining up with the correct maximum aperture after indexing.

Ronnie

 

[John Koehrer]

It is an FT. The max f indicator on the bottom of the lens mount shows this. It must
be set manually.
To mount and INDEX a lens on it, before installing the lens; the coupler has to be moved
CW until it stops.

FWIW Looks like the lens is a wide angle so the metering area is probably wider than the cell phone app.
If that's true, they're never going to match.

 

[ronnies]

It is an FT. The max f indicator on the bottom of the lens mount shows this. It must
be set manually.

The ASA scale on the bottom of the lens mount shows it's an FTn not an FT.

Ronnie

 

[Leigh B]

The variable resistor in early models was a metal ribbon.
The resistance elements were painted on it with a paint brush

Those have not been made in 50 years.

They often failed when the cameras were new, resulting in faulty or no readings.
Their reliability has not improved over the intervening 5 decades.

- Leigh

 

[cooltouch]

It's easy enough for Callie to determine if it's an FT or FTn. The "n" has the plastic tip on the film crank and an "N" on the top plate.

I wanted to point out what Leigh mentioned. This is the Achilles heel of the Nikkormats (and Fs and F2s as well). I have cleaned an F's variable resistor with Q-Tips before, which actually restored proper function. But if the elements are worn through, then the only alternative is to replace the variable resistor. Only problem with that is, the replacement part must come from a donor camera, and one will hope that it is in better shape than the one being replaced.

I recall -- but don't recall the specifics -- that there is a repair guy who refurbishes these variable resistors. So if he's still doing this, it might be worth approaching him. Whoever/wherever he is. Anybody else remember this guy?

I'm doing a google search on this topic and ran across a post by Rick Oleson at the now defunct Classic Camera Repair forum about the FT/n Nikkormat:

"A common problem in Nikons and Nikkormats is that the meter needle jumps wildly as you turn the aperture or shutter dial. This is usually fixed by cleaning a resistor in the meter. In the Nikkormat, this is located behind the lens mount - in the Nikon F and F2, it is in the prism. I have some notes for the Nikkormat and Nikon F, but not for the F2. If you would like the notes, please email me at rick_oleson@yahoo.com (my notes are for the Nikkormat FT, but the FTN is very similar)"

My google search revealed a few other sources that seem to be able to repair Nikkormat meters, but be prepared to pay for these services.

 

[Huss]

Your meter reading in the FTn shows overexposure. It is meant to be in the middle, not touching the top of the bracket.
Looking at that scene I'd say the correct exposure is 1/250 at f4 with 800 ISO film. Or 1/500 at f2.8 for the aperture that you are using. Which means you are still overexposing by 3 stops, which is much more than what your VF needle indicates. If you center your needle you may be 'only' overexposing by 2 stops.
As others have mentioned - what batteries are you using? You cannot use regular SR44/LR44 1.5v cells. This is why I use the FT2 Nikkormats as they use modern batteries.

As for those apps screen shots - the second one looks decent, giving an exposure that is correct for a maybe low key look. What is the name of that app? The first one is junk - I'm guessing it is Pocket Light Meter? This is another example of why I gave up on that app.

 

[cooltouch]

Your meter reading in the FTn shows overexposure. It is meant to be in the middle, not touching the top of the bracket.
Looking at that scene I'd say the correct exposure is 1/250 at f4 with 800 ISO film. Or 1/500 at f2.8 for the aperture that you are using. Which means you are still overexposing by 3 stops, which is much more than what your VF needle indicates. If you center your needle you may be 'only' overexposing by 2 stops.

I don't mean to pick nits here, but I'm pretty sure that the exposure difference between a centered needle and when its touching the top of the bracket (or bottom, far as that goes), this indicates 1/2 stop of difference. Thus overexposure would be more like 2-1/2 stops, not 2.

It also bears mentioning here that the chosen subject for metering appears to be a lightly colored concrete floor. Any meter will interpret its scene as 18% gray, thus this FT(n?)'s meter will be underexposing this scene by probably a full stop in order to achieve that middle-exposure value. So for proper exposure, one would want to open up things a full stop. (Note that the meter is already showing its opened things up by a half stop) A scene such as this is probably 3 or 4 stops off from "bight sun," so if we do the arithmetic, I'm getting about the same numbers as Huss. Open it up to counteract the meter's tendency to meter the scene as 18% gray, and it seems to be two to three stops off.

There is no way in the world I trust meter apps for cell phones. I've tried several, and they all just make me laugh, they are so inaccurate.

 

[callie]

Is this the N you are referring to?

 

[callie]

Hi Guys,
I have an update, firstly I want to thank all of you for the helpful insight.

I took the camera in to a local 2nd hand / vintage camera store to check out the light meter. Turns out they have an identical setup there just a chrome body. I tested both, my lens on both bodies, swopped batteries and no matter what combination we tried my cameras reading were off. For one test we used the same asa, the aperture and used the light meter to gauge the shutter speed. My cameras needle was in the middle at 1/4 whereas the shops camera was at 1/250The apps I downloaded also hovered around the 1/250 mark....

So the camera tech guy said I should return it as he is convince the metering is broken

 

[cooltouch]

Yep. Yours is an "N". Sorry, mis-wrote on the plastic tip.

Well, perhaps not broken, but certainly way out of spec. Like six stops off, by my count.

 

[ronnies]

The plastic tip was the ft2

The plastic tip was introduced towards the end of the FTn production. I have one FTn with the plain metal wind lever and one with the plastic tip.

Ronnie

 

[cooltouch]

Okay, so I was right, then . . . sort of.

 

[flavio81]

Hi Guys,
I have an update, firstly I want to thank all of you for the helpful insight.

I took the camera in to a local 2nd hand / vintage camera store to check out the light meter. Turns out they have an identical setup there just a chrome body. I tested both, my lens on both bodies, swopped batteries and no matter what combination we tried my cameras reading were off. For one test we used the same asa, the aperture and used the light meter to gauge the shutter speed. My cameras needle was in the middle at 1/4 whereas the shops camera was at 1/250The apps I downloaded also hovered around the 1/250 mark....

So the camera tech guy said I should return it as he is convince the metering is broken

You have a FTN as they indicated.

The FTN has this mechanism that tries to "auto-index" the aperture of the lens. Which requires that you mount the lens and then twist it back and force, as the manual says (of course you have already read the manual, right?) LOL...

So first the mechanism needs to be checked for correct operation (read: clean, lubricate) because otherwise it will not do the auto-index correctly. And this would explain why the meter is SO off!
Said mechanism is underneath the plate that says "Nikkormat" (or "Nikomat" if you're really lucky)

Next, as mentioned by cooltouch, the resistor plate around the lens mount might wear down. The way to check for this is to watch the meter needle movement while you shift speeds (or apertures). If the needle "jumps" this is due to faulty contact in the resistor brushes (or a worn down / dirty resistor surface). So this needs service: that part is dissasembled, cleaned and assembled again. The wiper brushes should do very good electrical contact with the resistor surface, but they need to do it gently so the surface lasts. So what they need to do is a COOL TOUCH.

Next, you need the correct voltage battery and the easiest way is to fit a #675 hearing-aid zinc-air battery cell. It is really easy to fit one in place of the original battery.

Now, after addressing these three items, the meter should be tested and compared with a known good camera or a true handheld meter. If the meter is off by 1 or max.2 stops then it can be re-adjusted by a technician. But after this adjusment the meter needs to be tested to see if metering on bright light AND metering in low light are (both) accurate. If one is accurate but the other not, the CdS cells require replacement.

 

[John_Nikon_F]

A few things:

The FTn went to the plastic tip stuff around 4435xxx, serial-wise. So, late 1972 or thereabouts. Leatherette changed at the same time.

With respect to a lens that won't index, take a small screwdriver or paperclip and press down on the tab just behind the coupling pin when it's at the minimum aperture for the lens. Then rotate the aperture ring back to the maximum aperture. That should cause it to index to the proper aperture, instead of sitting at f/1.2 and showing a very erratic meter. Other causes of an erratic meter can be the shutter speed ring shorting out against the metal strip. Seems to be more common on the FT2 and FT3 bodies than the FTn bodies. If the aperture ring causes a smooth movement of the needle, but, if you lightly touch the shutter speed ring and the needle pegs at full-overexposure, it's that problem.

To test for dead cells: one thing you can do is set the ASA to 400, set the shutter speed to 1/60, and the lens to f/8. Leave the lens cap on. Meter needle should remain at the full underexposure position. If it centers, then at least one of the cells has failed. Usually shows up as a cell that looks gray, instead of white with the red etching inside the window of the meter cell.

Since the camera is saying 1/4 second when the shop's FTn is saying 1/250, I'm thinking there's some corrosion, maybe on the wire going up through the body either to the meter movement itself or to the power switch at the advance lever. It's not uncommon to have corrosion that's not visible in the battery box, but in the wiring itself. Had a couple FTn bodies that were like that. Except the meters were completely dead. Battery chambers had some minor corrosion, but cleaned up nicely. Still no power to the meter. Pulled the top and ran a couple wires to the battery itself. Meter worked. So, the wires going down through the casting had corroded internally.

To the OP, it might be best to just buy the shop's body and let them either take the other body in on trade as a parts camera, or use it for parts, if the original seller is unwilling to refund your money. I suspect they would be willing to refund it, since you can prove that the camera is not performing as it should.

 

[twelvetone12]

@cooltouch Do you happen to have any photos of the variable resistor underneath the nikkormat lens mount? I have one that exhibits the same erratic readings as in your post.

 

[cooltouch]

Twelvetone (like your handle, btw), I have never serviced a Nikkormat's meter. I have serviced the wheel on a Nikon F before. It's pretty self-explanatory, though. Once you've dismantled the mount down to the resistor, just visually check the resistor for dirt or crud build-up. I just used a Q-Tip with alcohol to clean mine. You might want to slightly flex the wipers to make sure they're making good contact. If it appears that your resistor has worn through in areas, then it's time for a replacement -- if you can find one.

 

[flavio81]

To test for dead cells: one thing you can do is set the ASA to 400, set the shutter speed to 1/60, and the lens to f/8. Leave the lens cap on. Meter needle should remain at the full underexposure position. If it centers, then at least one of the cells has failed. Usually shows up as a cell that looks gray, instead of white with the red etching inside the window of the meter cell.

John's test is very good , but note that "dead cell" is not the same as cells that have aged and thus lost linearlity, which is the problem I indicated. When you have "aged cells", the meter works, but it can't be calibrated to meter correctly at the full range of ambient light levels (EV 17 to about EV 3)

Of course, with a dead cell the problem should be even worse, however i've never found a 'dead cell'.