General service information - Zeiss Contarex
The Contarex was unjammed by a tech in the Ukraine, had a damaged back replaced with a NOS item and I serviced the lens myself.
The Contarex is a handful and has proven to dislike the cold weather. The shutter hung for anything from a split second to a few seconds prior to finishing the exposure cycle, this does not occur if the lens is removed so I guessed that Henry Sheerers commentary was accurate and some aperture linkage problem prevented the exposure from finishing as it should.
I opened the wind-on as far as I could without the specialist tools needed. I was able to apply some Ronsonol sparingly to the exposed gearing and loosen up the wind on, applied fresh lubricant to the lever mechanism - it runs on surface metal to metal - no bearings or shims.
As I could not solve the riddle of top-removal I turned my attention to the aperture control ring. The lens aperture ring runs freely and so that was not the issue. I also tested the sequence without the lens attached and found the shutter did not hang. I then depressed the button (on the camera itself) that is moved when a lens is attached to it's mount and it caused the shutter to hang - so the shutter sequence hangs when the lens button on the camera bayonet mount is depressed mimicking the situation of the lens attached to the camera since the mounting of the lens depresses this button. This is the button that lies at the 11.00 o'clock position on the camera lens mount - it can be seen in the picture, pointed at by the meter iris lever. I discovered that this button introduces an idler gear into the system.
I removed the lens bayonet mount from the body. This exposes 3 shims that adjust the film plane distance, these simply fall way, you can see one in the picture - the chromed shim bottom left quarter.
The lens coupling ring is underneath the bayonet mount - it is the black ring that has the aperture coupling tab at the exact 9.00 o'clock position on the inside of the ring (see picture). This ring is held by 2 screws at 10 o'clock and 5 o'clock. remove these and the coupling ring lifts out. You will be able to see the following:
1. At 5 o'clock - The spring charged gear wheel that powers the aperture ring return
2. At 7 o'clock - two connected idler gears that set the aperture stop - these need to be turned until they stop when re-fitting the black aperture control ring
3. At 9 o'clock - The idler gear that is engaged by depressing the button on the lens mount, this is moved into engagement by the button when the lens is attached (button at 11 o'clock - see comment above)
4. At 10 o'clock - further gears linked to the meter iris and the thumbwheel that sets the aperture
All of these have to spin as freely as possible to ensure the shutter cycle is not impeded and therefore does not hang. I doused them with Rosonol on the end of a Q tip and spun them and moved them about as much as possible. I also thoroughly flushed the black aperture ring in Ronsonol and left to dry there are no springs in this just 2 rings running on bail bearings. As far as I can deduce, there are no spoilable parts in this area of the camera and so any wayward Ronsonol will likely migrate slightly and evaporate without concern.
To test I simply refitted the black aperture coupling ring without the screws and cycled the shutter while depressing the button at 11 o'clock. Success! A good clean has freed the system and the shutter fires consistently. The aperture control system also works with less effort and feels smoother and more responsive. No lubrication was applied. It passed a short shed test at ambient 10 degrees C and now sits on the shelf for a week or two to see if it settles down.
To re-fit the parts care has to be taken to set the various gears into position.
The gear in point 1 above - turn until the spring is just beginning to tense, re-fit the aperture control ring by dropping it in from above so that it sits just tensioned by the gear - no slack at all. The ring has to be jiggled very slightly to re-engage with all the other gears
The gears in point 2. above - wind them until they stop, too difficult to explain in words which direction - they either will be correct or not. To test this I re-fitted the black aperture ring with out screws mounted the bayonet with just two opposing screws and tried it - first time unlucky second time OK. If not wind them in the reverse direction until they stop and try again.
Set the aperture to the minimum on your lens - in my case F16
This camera was designed at the same time as the Nikon F and when looking at the various solutions each brand arrived at it is easy to see why the Contarex acquired a reputation for unreliability. Nikon chose the simplest aperture control system that works and returns the lens to full aperture viewing. Zeiss chose the most complex of linkages that shackled them to a limiting aperture system and a less accurate result. A flawed system, beautifully executed
The F2.0 Planar lives up to it's reputation as the finest lens of it's time, the Contarex has an immensely satisfying shutter sound as if a great deal is happening - which is the case - and if the house was burning down I would save my Nikon F2.
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