Only 1/4 of each negative exposed?

[pietb961]

Hey all,

Just developed two rolls of film shot today and ran across a problem I've never had before. One roll is almost completely unexposed except for portions of a few frames. On the second roll, only about 1/4-1/3 of each frame is properly exposed, and the rest is completely empty. There's a slight angle to the cutoff point on each frame which is suggesting to me that the mirror and curtain shutter are off-sync, so that the film is only partially exposed. This happens across multiple shutter speeds and apertures. The size of the exposed portion is relatively consistent.

Just fyi, I'm using an Asahi Pentax Spotmatic body. This is the first time I've had this problem.

Any advice appreciated. Very sad day!

 

[Sirius Glass]

The shutter needs a CLA.

 

[pietb961]

That's what I was worried about. Really love the camera and got it for only $20 so it'd be worth it. If I get a CLA, anyone have advice for a reputable Pentax repair shop, preferably in/near NYC?

 

[winger]

You'll need to mail it rather than drop it off, but this guy is the best - http://pentaxs.com

 

[pietb961]

Thanks!

 

[wiltw]

Which direction on the film is the partial frame?
The Spotmatic shutter curtains move horizontally across the film plane so that there wouid be a band which is fully across the short dimension of the frame, if the shutter was acting up
The reflex mirror moves vertically so it would cut off parallel to the long direction of the frame
If you saw cutoff in both directions, there is an interaction between the shutter and the reflex mirror

(After I made the drawing I realized that the mirror issue has the greyed out area at the wrong portion of the frame, it would be along the opposite end.)

 

[pietb961]

Its the first drawing - therefore a shutter issue.

If I slow the shutter speed down to 1/4-B, I can see the curtain open completely, so is it not that the reflex mirror release and shutter are out of sync?

 

[wiltw]

Its the first drawing - therefore a shutter issue.

If I slow the shutter speed down to 1/4-B, I can see the curtain open completely, so is it not that the reflex mirror release and shutter are out of sync?

The curtains should open completely at 1/60, the X synch shutter speed, and be fully open at any speed slower than that.