Canon L1: Tapering Yes or No?

[David Murphy]

I film tested my Canon L1 today with a Voigtlander 35mm F1.7 Ultron. The shutter speeds were all 1/250 and the lens was set typically to F11 +/-half a stop or so (ISO 200 color print film).

Question. Do you think this shutter is tapering a bit? Any other opinions?

 

[dberger]

I film tested my Canon L1 today with a Voigtlander 35mm F1.7 Ultron. The shutter speeds were all 1/250 and the lens was set typically to F11 +/-half a stop or so (ISO 200 color print film).

Question. Do you think this shutter is tapering a bit? Any other opinions?

Tapering is not obvious to me in these shots. The shutter is certainly not tapering completely shut before it completes the frame, at least at this speed, or else you would see black vertical bands on the right side.

If the shutter is tapering a bit, I guess you would see some underexposure on the right hand side, but it would be hard to see, especially in outdoor shots with varying lighting conditions across the frame.

If there is mild tapering at 1/250, it should get worse at 1/500 and 1/1000. If the shutter is tapering shut at high speeds, you can see it by holding the camera (no film, lens, or body cap; back door open) up to a bright evenly lit wall or sky and fire off a few. If you do not see a uniform full frame, there may be tapering.

Regarding the 35mm Ultron, of which I have no experience, it looks like f11 a stop or 2 beyond its peak performance (images just do not look that sharp). Then again, it is hard to tell on a computer screen.

cheers,

David

 

[David Murphy]

Thanks for the astute comments. That's about the sharpness I get with cheap ISO 200 film and a Dimage scanner. I can do better with say ISO 64 Kodachrome, but it's bad for testing cameras since it takes two weeks and C41 is processed down the street from here in 30 minutes.

OK, I had the shutter checked on a shutter tester today by my repair tech and he told me that while he did clearly notice tapering, most of the shutter speeds were about a stop fast -- a sign it needs some work. He'll adjust it and make it right. The L1 is a fine camera and well worth it. I'll run a complete series of tests on a uniformly illuminated white or grey target when the camera comes back as per your suggestions.