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Problem using a 50mm AE lens on a 167MT

G

Guest

I've just received a 167MT that I bought on ebay, and am surprised to find my 50mm f.7 AE lens won't function properly on it in AE or manual modes.

The camera is always detecting the aperture to be f16, and this does not change even when I vary the aperture of the lens. The shutter speed is also being set as if it is a f16 lens, with long exposure times that do not get quicker when I open up the lens aperture.

I'm wondering, is there a problem with the camera, or the lens? Or perhaps something else - I don't have an instruction manual for the camera.

Also, my f8 mirror lens is being detected as a f4.5 lens.
 
G

Guest

I've just tried the camera with two old 135mm lenses, both AE's. In both cases the camera detects the aperture correctly. But the 50mm lens works fine on a Contax 139. Strange!
 
G

Guest

You've tried the complete problems diagnostics? What happens when the 50mm lens is on the 167MT is twisted at the lens barrel (not the aperture ring) clockwise or anti-clockwise?

Does the aperture still stay at f16? It sounds like a prob. with the contacts at the lens mount interface, if you've already excluded the meter as being at fault.

Mike
 
G

Guest

Don't know what you mean by "twisted", Mikhail. Do you mean turn the focus ring - if so then that makes no difference.

When the lens is set at f1.7 and then put on the camera, the camera correctly says f1.7. And when I then step down the aperture it correctly displays all the descending f-stops. But once I reach f16 the display (and the exposure reading) stays at that and does not change when I open up the lens to f1.7 again.

On the lens there is a small bend at the top of the "aperture linkage lever" - the thing that is marked as "No. 3" on the photo that is on the "Please explain difference between AE and MM lenses" thread at the top of this board. But I don't know if the lever on all 50mm AE lenses are like that or if it is perhaps damaged and not linking with the camera properly.

Certainly, it was like that when I bought it second-hand last year as a rushed replacememt to my 45mm tessar that I dropped and lost in deep snow (I still shed a tear about that!). And it works fine on the 139.

So, could someone look at their 50mm lens and tell me what their aperture lever is like - straight or bent outwards slightly at the end!
 
G

Guest

this sounds strange to me because I previously owned a 139 and now have a 167mt, and had no problems with my 50mm lens on either. This is the same for my 28mm, 40-80mm and 135mm.
 
G

Guest

Steve,

1). rack down the aperture to f16 and look at it from the lens towards the mirror, and rack back up towards 1.7. Check with depth of preview. Do the aperture blades disappear? If no, you may have a problem with your lens coupling.

2. Grip the whole lens mounted on the 167Mt (not the focusing ring, nor the aperture ring). When you try and force the whole lens clockwise or anti-clockwise - do the exposure readings stay the same? If they do, it's probably not the lens mount at fault.

3. The aperture lever on the AE lens is straight. Perhaps slight angled as it starts out from the inside of lens. Not bent.

4. Perhaps wait until other Contax users wake up, and you'll get more info.

5. Still sounds like lens-coupling-mount interface problem to me. If the mirror lens is still reading f4.5, and the aperture is 'sticking' at f16 on the standard lens. You have checked the meter and replaced the batteries, haven't you?

Sorry to hear of the Tessar's demise. To be buried in the snow is unfortunate. You should be able to get a copy of the 167MT instructions from Contax, or possibly on this website. I have a copy somewhere, but not seen recently.

Mike
 
G

Guest

Hi there Steve,
My 50mm F1.7 aperture coupling lever has a slight bend upwards. It works fine on both the 139 and the RX.
Paul
 
G

Guest

Steve,

It may not apply, but my p85 had the same problem after a small drop. The mounting ring that is part of the lens was bent slightly in a fall.
The ring is attached by 3 screws to the rest of the lens body.
The bent ring was making contact with a lever at the top of the lens opening on the camera body.
After straightening the ring all was well. Your new body may have less clearance between the parts than your other bodies.
Hope this helps.
 
G

Guest

Hmmm ..come to think of it, the mounting ring is very slightly bent, by only a really tiny amount, but I'll have a go at straightening it.

It's actually surprising how badly made the lens mount is, you would expect it to be a solid bit of metal casting like even the most inexpensive independant lenses have, but it is just a cheap and flimsy bit of sheet metal.


Plus, answers to mikhail's suggestions:

1/ the blades do move in and out when the dof preview button is pressed.

2/ the exposure readings don't stay the same.

3/ There is just a slight angle at the end.

5/ new batteries, and the meter seems OK.

Thanks all.
 
G

Guest

I straightened out the tiny bend - which was just big enough to slide the edge of 2 sheets of paper between the mount and rest of the lens. And the lens now seems to be working as it should! So that seems to have been the problem.
 
G

Guest

Congratulations Steve. You have solved the problem! Now you have checked the 500mm Mirotar isn't reading f4.5?!
 
G

Guest

Its not a 500mm Mirotar, but a 600mm f8 mirror made by sigma - which gives excellent picture quality by the way! But it is still reading f4.5 <font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">•<font color="ff0000">• reads f5.6 on the 139, but the actual exposure seemed OK most of the time, except that if sunlight entered from the viewfinder the film would be under-exposed. Or maybe the f5.6 reading was affecting the exposure?? I'll need to try it on the 167MT with the spot metering on.
 
G

Guest

Search me Steve.

They look interesting. The red.dots add life to the grey board
I presume. Without them, life would be


Your viewfinder doesn't shouw these I guess!

Have not seen a mirror lense in action; I understand the focussing is different or difficult compared to twist barrels. The 167MT is a very good size and shape for most lenses anyway.
 
D

davidfung

(Also posted in another thread) Hi, I have a similar problem. I recently acquired a 85/1.4 AE. Using it on my RTSII is no problems, with the aperture read out correct regardless of which direction I rotate the aperture ring, and how I mount it. However, when it is mounted on my ST (in very good condition), the aperture readout only goes downwards, and never back up. For ex&le, if the lens is at 1.4 when I mount it, it will go to 2, 2.8, etc, all the way to 16. But it will never go the other way, say from 16 to 11, 5.6 to 4, etc. Has anyone encountered this problem? It sounds more of a problem with the body then the lens. Should I get the lens and ST serviced? Or is it something I can do myself. Thanks for your input.
 
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