Contax IIA/IIIA shutter curtain gap.

[campy51]

I did a mild cla on my Contax IIIA and before I did that the 1/1250 speed had no opening at all. All speeds seem fine to the ear and eye but the test roll showed very inconsistent photos. Some my fault but not all. My question is how do I tell if the opening is at proper width between curtains? In the photo below you can see that the opening is not parallel to the camera but the opening itself looks even. Is this a problem and how do I correct it? The first one is at 1/1250 and the second one I think was 1/100.

 

[awty]

The curtain ribbons probably need to be repaired or replaced, roller mechanism needs cleaning, lubing.
I replaced mine. https://www.photrio.com/forum/threads/contax-ii-ribbon-replacement.194491/

There are a few how to's on the net.

 

[campy51]

The ribbons looked fine when I had it apart.

 

[OAPOli]

The tilted curtains are an artifact of the rolling shutter I think. What are the symptoms of the "inconsistent photos"?

I don't see a big difference in the slit width between the two pictures. It should gradually get wider the slower the exposure time.

Without a better tester it's hard to determine exposure time. But high speed video can help check if there is gross imbalance between the curtains.

In principle if the sync speed is 1/50, the slit width is 24mm; 1/100 --> 12mm; 1/1250 --> 1mm (that's almost impossibly small).

 

[swchris]

How did you take the pictures? The non-parallel curtains are probably an artifact of your taking camera if it uses a horizontal shutter.

 

[campy51]

I did a slo-mo video with my iphone and then a screen capture.

 

[Don_ih]

I did a slo-mo video with my iphone and then a screen capture.

Do the same video but rotate either the camera or the phone 90 degrees and see if the shutter remained angled like that. It's possible the angling is the result of how your phone registers the contents of the sensor.

An angled shutter would definitely result in inconsistent speeds. But I'd think it would also look angled as you cocked it.

 

[campy51]

Here are some more. The 1st one is 1/100, 2nd 1/250 and the last one is winding the shutter.

 

[campy51]

I just developed my test roll and everything looks good so my cla worked out.

 

[Don_ih]

That's good. The shutter also looks pretty normal (to me) in your phone photos.