Contaflex Super BC loose optical mount

[bernard_L]

This is --partly-- a follow-up to an oldish thread about double images:

Ghost image with Contaflex

Made the first test of my second Contaflex (Super) body, bought last June. Some images show a ghost image, offset from the main image by a small amount. Most noticeable on pictures taken with the 85mm pro-tessar. Some pics with the same 85mm (and same body) do not show that problem. Still unsure...

www.photrio.com

Returning to that camera, I noticed that, grabbing the front element, I could move it very slightly, the tactile input confirmed by the sound.
I embarked into an overhaul of the camera body; the Super BC is more over-engineered than the contaflex I or II. After dis- and re-assembling the lens assembly to the front plate, and the front plate to the camera body, the wobble of the front element had disappeared. Joy! A few test frames... double images still here.

Then, having removed the front element (bayonet mount) I now grabbed the center element, and... it wobbles. Very little, but it wobbles. And the slack is somewhere between that element and the base of the shutter assembly (that interfaces with the front shutter plate). Pretty little documentation about the shutter assembly. The Zeiss service manual considers it as a single component. The Deckel manual just gives a (partially) exploded view and some cutaways in the lubrication section. So I unscrewed the middle element, then removed the light baffle plate, the speed cam and main ring. See below

The screws securing the brass barrel A to the black baseplate B are tight. But the baseplae B jiggles slightly with respect to the aluminum casing C. I an reluctant to dis-assemble the shutter components: will lose speed adjustent which sounds OK for now.
Question: where are the screws that fasten B to C ?
Thank you for reading

 

[bernard_L]

For the convenience of viewers, and to avoid going back to that old thread, the problem can be summarized in this 2017 image of a 220V tungsten lamp powered at 120V, and photographed at ~3m distance.

 

[matt1899]

I've also got a Contaflex Super BC with a loose optical mount. Can you tell me how you got the shutter loose? The Super repair manual mentions 3 screws, but these are hardly reachable in the Super BC.

 

[bernard_L]

I've also got a Contaflex Super BC with a loose optical mount. Can you tell me how you got the shutter loose? The Super repair manual mentions 3 screws, but these are hardly reachable in the Super BC.

First the three screws. If you need to remove them, you better remove them from the back. Granted, one of them can be accessed only in an oblique way. That is still OK if the screwdriver blade fits snugly; I checked, and a Wera 0.4x2.0 fits just right; the blade thickness being the most important parameter.

In my case, I started on the SuperBC after repairing a ContaflexII. For the CII separating the lens is simpler --a retaining ring-- partly because the front-element focusing simplifies the linkages between body and lens. Why this digression, you did not ask about the Contaflex II? Read on. For the CII, the problem was in the gear train between the advance/cocking knob and the lens. So I had to remove the top of the body.

Moving on to the SuperBC, and seeing how the access to the three screws was oblique, I did it the hard way. Remove the front plate (four screws at the front, under the leatherette); but the plate won't come off if the top is not lifted. It's crowded underneath. Re-assembly, esp. the galvanometer, is something. In retrospect, I would have unscrewed the three screws from the back. Even so, when putting back the lens assembly, you need to make sure all the linkages fall in place.

Back to your problem. "Loose optical mount" can have several causes.

• Front plate loose against chassis. As mentioned previously, four screws on the front, under the leatherette, on either side of the lens.
• Fixed part of focus helicoid against front plate. The infamous three screws.
• Some play in the focus helicoid. Unlikely IMO.
• Optics (except front element) loose against moving part of focus helicoid. That was my problem; see my post #1 above. The culprit screws were hidden below some of the shutter components, but I could leave the escapement in place and did not lose the speed settings.
• Front element sits on its own flange, hat might be loose.

Good luck!

 

[ic-racer]

Great pickup on that!

 

[bernard_L]

Just so you know what you are stepping into if you remove the top.

Below is the galvanometer prepared for re-installation. You are looking a the underside. The galvanometer fits in sort of cavity, so one does not see the underside during assembly. The green thread (Polyethylene fishing line) is holding back a spring-loaded lever. That lever must go on the proper side of another lever emerging from the chassis at the bottom of the cavity; the two cooperate to tell the meter what shutter speed has been selected.

So you carefully lower the galvanometer into the cavity, then release one end of the green thread, and carefully pull the other one. Then check that speed settings on the Compur barrel are reflected properly in the viewfinder display.

 

[bernard_L]

The OP seems to have left the room.
Maybe thinks photrio is some kind of IA bot. Ask question. Read answer. Done.

 

[matt1899]

Thanks for your reply. I have the impression that tightening the three screws seems to improve it, but it's still a bit loose. This is even more evident with one of the tele-lenses attached.

I do have a difficult time understanding how the focus mechanism holds together. The three screws (from inside the camera body) screw into the shutter and lens assembly. But that entire mechanism moves with respect to the body as well?

 

[bernard_L]

I do have a difficult time understanding how the focus mechanism holds together. The three screws (from inside the camera body) screw into the shutter and lens assembly. But that entire mechanism moves with respect to the body as well?

That is indicated in my post #4 above. Rephrasing:

Starting from camera die-cast chassis.

• front plate fixed by 4 screws, accessible from the front under the leatherette
• fixed part of focus helicoid, fixed by the 3 screws reachable through the film gate
• moving part of helicoid, connected via the focus ring and the helicoid grooves
• casing of shutter/aperture mechanism; note that this is a compur (Deckel) part; I do not remember all details
• ring baseplate for the shutter mechanism
• barrel for the middle and back groups of the Tessar, held to the ring baseplate by 3 screws partly hidden under some parts of the shutter mechanism; see post #1 above
• support for the front element of the Tessar, a brass piece with breech-lock system for interchangeable elements; connects directly to the casing of the shutter/aperture

Any of these might have a loose fit with respect to the previous one in the list.

Grab the front element. Do you feel it moving? Any small motion, hardly detectable, can have a detrimental effect on sharpness.
Remove the front element. Grab the rim of the lens (middle element). Do you feel it moving?
Peel away the leatherette either side of the lens, enough to uncover the four screws; Are they tight?
You already checked the three screws inside the body, through the film gate.

These are the easy checks. If you do not feel comfortable with a relatively complex assembly and re-assembly, your best bet is to buy another body-only camera.

Below: fixation of the front element breech lock to the outer rim of the shutter/aperture casing.

Dis-assembled shutter/lens.

 

[matt1899]

Thanks! Hopefully I'll be able to give it a try this week.