Nikkor H-C non-AI Lens - Meter Coupling Problem

[larry davis]

I picked up a black Nikkormat FTn body on eBay recently and then bought a 50mm

f/2 Nikkor H-C non-AI lens for it. The meter works but only in the step-down

mode - that is only when holding down the Depth-of-Field preview button. I'm

pretty sure the lens is mounted correctly - set at f/5.6, pushing the coupling

pin all the way to the right, inserting the lens while engaging the coupling

pin in the slotted prong, turning all the way to the left until locked, then

indexing the aperture ring all the way to the left and right. But when looking

though the viewfinder (with the wind lever out so the meter is on), no movement

of the meter needle (always in the + range) unless I press the DOF button. Am I

doing something wrong? The aperture of the lens when off the camera is as set

on the aperture ring and when installed on the camera is wide open. Also, the

little meter needle on the top of the camera also requires the DOF button to be

depressed to work. Is this a body or lens (or photographer) problem? Thanks in

advance for any advice.

[photo5]

Sounds like the coupling is probably damaged. They are very old cameras from the 60s. Well, at least you still have stop down metering!

[bob_sunley]

Well, what are your asa and shutter speed settings. Metering on that camera is always with the lens wide open, unless you have a lens with no coupling shoe. On the shutter dial, does the little pointer for the aperture index point to the right value? What type of battery is installed in it? That camera only works properly with a 625 mercury(unobtanium now) or a wein cell. Regular alkaline ones throw the metering off a couple of stops. I have a nice chrome fully functional one sitting on my desk in front of me.

[larry davis]

Bob, the ASA is set at 100 and the speed at 1/125 - also tried other settings. The aperture index correctly points at 2. I am using a jury rigged 1.4 volt 675 zinc-air hearing aid battry (smaller diameter so I use a strip of rubber to make the battery fit tightly). Seems ok since the stop-down metering method works.

[bob_sunley]

Welllllll.......... there is a ring resistor under the shutter speed ring that can have problems in its old age, but that usually results in a low reading.

 

Does adjusting any of the settings cause the meter needle to move other than the DOF button? Does moving the shutter speed dial make a difference when the DOF button is depressed?

 

Can't be a lens problem as the only thing the lens does is move the coupling pin. It's possible one of the internal wires is shorted or one of the wiper arms is off track and shorting to the chassis.

[kelly_flanigan1]

There is a resistor ring around the lens mount. The coupling pin is on this ring. The asa setting gizmo is on this ring. The contacts often get crudded up. Indexing lets the body know what *wide open* fstop the lens is. Stopping down moves the pin in the fork; the fork moves the resistor contact. Place a body cap on the camera; one of those thats milky like a milk jug; but still allows light to pass. Position the body with meter on so the meter is centered; rotate the pin around the lens mount. The meter should move without any jerks; unless its cruddeed up. Often tbe ring is NOT worn out; its like a scratchy volume controll and needs so movement to get a good contact.

[kelly_flanigan1]

Pressing the DOF button stops the lens down; this should move the meter. The meter should also move whern on turns the fstop ring from F2 to F2.8.

[JDMvW]

My Nikkormat FTn meter just stopped altogether one day not long ago. As Bob said, the resister ring is a weak spot in its old age. But I don't understand why the needle would be in the plus range.

[scott_warn]

Check to see that the lens is indexing properly. On the side of the aperture ring follower, near the lens release button, you'll find a cutout with various apertures engraved on it. Within this cutout you should see a red dot next to the maximum aperture for your lens. If the red dot is at the 5.6 indicator, the lens didn't index properly.

 

These mechanisms can get gunked up with age and sometimes you just have to play with them to free them up. Take the lens off the camera and repeatedly swing the indexing pin throughout it's range. If you hear a click when you swing the pin past straight up, watch the cutout when you sart moving it back home and you should see the red dot start to shift in that cutout. You should also hear the pawl clicking as you pass each indexing point. If all that happens, you've freed up the indexer. If it doesn't, it's either use the stop down metering or take it to a repair shop for a good cleaning. BTW, if you get it working just sometimes, just keep exercizing it until it's totally free.

[JDMvW]

Wait, what is your film speed set at?

[larry davis]

Ok. Great feedback. Let me see if I can address it all ... if I depress the DOF button, I can move the meter needle by rotating the aperture ring. If I try to also move the needle by rotating the shutter speed ring while depressing the DOF button, I get a bit of movement, but not what one would expect, not like the aperture ring effect. I did try the milky body cap - moving the pin does not move the needle at all. The meter needle is in the (-) end when off and jumps to the (+) end when it is turned on. The indexing looks to be correct. When rotating the pin back and forth, however, the movement feels gritty to me, not nice and smooth. There is a clicking at the top center. Moving it back and forth numerous times has not helped. Tomorrow I will check some meter readings outside with nice bright light and compare them against my digital camera to see if even the stop-down readings are right. I have a feeling a CLA is in order, although that tends to cost more than the camera is worth. At least I think I can take shots using a light meter, as these good old cameras work fine without the meter or battery. Thanks agian. I'll let you know how my tests go tomorrow. Larry

[doug herr]

Since the meter needle is not (or barely) responding to the shutter speed I'd say your

resistor ring isn't working correctly, either from dirt/gunk or because it's worn out.

There's only one set of contacts on the resistor ring and its position w.r.t to the ring is

influenced by the shutter speed selection, aperture selection, maximum aperture of the

lens, and film speed selection. Since the meter reading responds to the stop-down

method the meter cells are probably OK (one on either side of the viewfinder eyepiece

IIRC).

<P>

If you'd like to repair the meter, start by getting a NOS mirror box assembly for the

Nikkormat FT2 from Pacific Rim Camera, then take the camera and the mirror box

assembly to your repair technician. The camera probably needs a good CLA by now and in

the process the mirror box assembly can be replaced. The mirror box assembly includes

the lens mount, shutter speed ring and resistor ring, and the FT2's mirror box is 100%

compatible with the FTN. While the camera is getting CLA'd have the meter calibrated for

a 1.5v silver-oxide cell.

[doug herr]

One more thought - before concluding that the resistor ring is the problem, be certain that

the shutter speed selector and aperture are in a reasonable range, i.e., sunny 16 or within a

few stops. Sometimes this camera's meter will appear erratic when the shutter speed and

aperture are out of range.

[larry davis]

Thanks everyone. I ran some tests today, and I must agree that the resistor ring is not working right. There is very little response to changing the shutter speed. It's as though the meter thinks the shutter speed and the film speed are always the same. I will contact Pacific Rim Camera, as you suggest, Douglas. Again, thank you all for responding with your good advice. Larry