Contax mirror slip consequences

Vaidotas · Dec 16, 2022

I just bought Contax 139 MA with Yashica ML 50mm f/2 and after quick check found that camera don't focus to infinity. It focus to max 5 meters.
Checked the lens on proper working Contax 139 and it appears the lens has no issues.
After visual checking mirror chamber there is obvious mirror slip to ~1-1.5 mm
There is a lot of threads about Contax mirror slip and how to deal with it but not much info about this malfunction consequences.
Question is - does mirror slip affects ability to focus in to infinity?
Or there is more than one problem?

koraks · Dec 16, 2022

Vaidotas said:
Question is - does mirror slip affects ability to focus in to infinity?
Or there is more than one problem?

The consequence is that when you focus using the viewfinder, the focus will always be off from what the film sees. So it's a problem that needs to be fixed if you want any of your photos to be in focus.

Vaidotas · Dec 16, 2022

Koraks, thank you for your thoughts, but we are still at zero point and my question remains unanswered.

koraks · Dec 16, 2022

Perhaps someone else will come along and formulate the answer in a different way. Something is clearly lost in translation.

Good luck with the camera and I hope you'll find a fix.

Vaidotas · Dec 16, 2022

koraks said:
The consequence is that when you focus using the viewfinder, the focus will always be off from what the film sees. So it's a problem that needs to be fixed if you want any of your photos to be in focus.

Koraks, thank you.
There is question again.
Does mirror slip affects ability to focus in to infinity?
I understand your statement, you are talking in general.
My question is very specific for a folks who had this problem. Are you one?
So - mirror slip affects vignetting in viewfinder, sometimes has a contact with lens bayonet, and misalignment between film plane and viewfinder.
But does it affects inability to focus in to infinity at this degree (5 meters max viewing through viewfinder).

koraks · Dec 16, 2022

Vaidotas said:
My question is very specific for a folks who had this problem. Are you one?

I had a more elaborate answer here, but given this stipulation I've removed it so you can get answers exclusively from the group you're targeting.

Good luck!

Vaidotas · Dec 16, 2022

Ok.
I left the camera at repair shop for mirror reglueing / calibration and promise to report how it goes within month.
I was a bit desperate with my questions just because in urge to make quick decision leave it to myself or return to seller. Apart mentioned problem camera is really neat.

gone · Dec 16, 2022

Mirror slip does seem to be an issue w/ your camera. The link below gives you info on a do it yourself repair, assuming that is your issue. It also could be that the lens has been apart at some point and wasn't put together again properly.

Contax Mirror Slip Repair

So I've purchased two used Contax cameras in the past week (an ST and RX) and BOTH of them have the mirror slip problem (what luck huh?). I read somewhere that applying a hair dryer to the underside of the mirror and then pushing it back into place works...and it does, for the time being. My...

www.photrio.com

Vaidotas · Dec 16, 2022

Thanks, momus.
The lens is ok as I stated in first post.
Thank you for the link, I read it and a lot of other sources before starting this thread as I stated in the first post.

ic-racer · Dec 16, 2022

I had a Yashica FX3 in which the mirror was not inserted correctly and I re-positioned it. I have never had one move on me. If the focus is off, maybe someone tried to re-attach a mirror with 2-sided tape that was too thick.

Also, the mirror adjustment is shown in the diagram here from the Contax manual (which also applies to the FX-3).

28mm f2 Contax hits mirror on Yashica Super 2000

I recently bought a 24mm f2 Contax and tried it out with a Yashica Super 2000 camera. Unfortunately, it hit the mirror, damaging it. Any ideas why? I'm not sure what to do. This is my fist Contax lens and SLR so I suspect user error, but I'm also wary that any manufacturer would allow this to...

www.photrio.com

cowanw · Dec 16, 2022

The problem when mine slipped was that the mirror and camera would not cycle, without removing the lens; not a problem with focus.

brbo · Dec 16, 2022

ic-racer said:
I had a Yashica FX3 in which the mirror was not inserted correctly and I re-positioned it. I have never had one move on me. If the focus is off, maybe someone tried to re-attach a mirror with 2-sided tape that was too thick.

But that would make the lens focus past infinity. Not reaching infinity means the mirror is too far back, doesn't it?

reddesert · Dec 16, 2022

If the mirror is attached with too-thick tape or is similarly displaced forward when it slips, then when the lens is set to infinity on the focus scale, it's correct for the film plane, but it cannot get close enough to the ground glass to appear to focus at infinity. That is probably what the OP meant by the lens doesn't reach infinity focus.

Edit: This is backwards as noted by brbo below.

brbo · Dec 16, 2022

Too thick a mirror or mirror attached with too thick a tape will be closer to the lens and ground glass - image will be focused past infinity on the ground glass. OP has an opposite problem.

reddesert · Dec 16, 2022

You are right, in that case, if the lens was extended (say 5 meters on the focus scale), it would appear to be focused at infinity on the ground glass. So we are back to the question of what the OP means by "camera doesn't focus to infinity." On the focus scale? On the GG? etc.

Don_ih · Dec 17, 2022

Vaidotas said:
Contax 139 MA with Yashica ML 50mm f/2

The ML 50 is not very well made (although it's a very good lens). Without much effort, one of those will unscrew from its helicoid when you focus on something up close. If that happened and someone screwed it back together, it may not be together correctly. You need another C/Y camera to check it.

brbo · Dec 17, 2022

Don Heisz said:
You need another C/Y camera to check it.

...

Vaidotas said:
Checked the lens on proper working Contax 139 and it appears the lens has no issues.

Vaidotas said:
The lens is ok as I stated in first post.

Don_ih · Dec 17, 2022

Very astute of you to point out my oversight, @brbo . Did you happen to have any ideas?

If the lens is fine, the mirror mount has probably been bent by someone playing with it (flipping the lens up with their finger or perhaps attempting to push a slipped mirror back into position). However, if the ground glass is in upside-down, that might have an impact. Don't know if the focus screen is removable on the 139MA (?) .... did you mean 137MA?

brbo · Dec 17, 2022

Problem with bent mirror mount would be rather easy to identify, the upper and lower part of the image would not be focused in the same plane on the ground glass.

All is pretty much irrelevant now, since the OP doesn't have the camera anymore at hand and also asked for people that don't know this camera not to comment in this thread...

Vaidotas · Jan 16, 2023

The Contax 137 MA camera is on my hands after mirror regluing, callibration and cleaning.

The problem was improper attempt to reglue mirror with wrong thickness of dual adhessive tape. By slipping, mirror accumulated glue residue more at the bottom of mirror support causing change of the angle with pentaprism.

Thanks everybody for brainstorming.
Now I’m going through first roll, nice camera, very comfortable but my thumb still looks for rewind crank.

Yashica · Dec 3, 2023

Hi Guys,

i pull this thread out again...my bad. I own a Contax RX (besides other 35mm Contax gear) which does have the messy mirror slip.
Do you know a decent camera repair shop, which could do this for a sensible price into germany ?

Thanks in advance.

PS: great to hear, the 137 MA is working. I own also the 137 MA & MD, one is wrapped into red artificial leatherette, the other into blue.

cowanw · Dec 3, 2023

It occurs to me that storage of these camera sitting on the bottom plate may encourage slip. Perhaps they should be left sitting when not used on their pentaprism top

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