xwhatsit
Well-known
Hello,
Was a sunny day at the beach so took my new Yashica YF. After souping the shots, noticed that 1/1000 (which I've hardly used yet) was capping rather badly.
The YF is a Nicca 5L facelift, which in turn was basically a fancy Leica-M style body with screwmount innards. As far as I am aware, it's a pretty typical Barnack shutter, with the slow speeds on the front etc.
I read about shutter capping, and after doing the CRT shutter test I decided that the 2nd curtain did have too high a tension.
Pulled off bottom cover, looks like somebody has been in there before. The YF has these interesting ratchet and pawl adjusters for shutter curtain tension. I backed some tension off (way too much, curtain wouldn't run the whole way), then tightened it up. It stopped capping, but the speeds were too slow.
So I spent an hour or so fiddling around with the second curtain's tension. Here are the weird things that are happening now:
Sometimes the shutter doesn't release properly on 1/1000; you press shutter release, first curtain is released part way (maybe the gap at 1/1000?) and the shutter won't continue. It'll usually carry on once you take your finger off the shutter release. Before I touched the 2nd curtain tension, it'd do this occasionally on 1/30 - 1s. This problem seems to be OK now with the current curtain tension I have it set to (which is slow).
When I up the curtain tension slightly (I think), 1/1000 starts capping in a different way: instead of closing the gap towards the end of the shutter cycle (classic 2nd curtain too tight, right?), the "fade" is at the beginning of the cycle instead. Doesn't happen every time.
Do these two things point to a problem with the shutter release mechanism instead of curtain tension? Or do I need to start adjusting the first curtain too?
Last thing: right now I know the second curtain tension is too low. Shutter speeds look too "wide" on the CRT screen. This has affected (I assume this is the cause) the slow speeds: 1 second sounds more like 1.5 or 1.75s. Not too worried about that yet, until I get the fast speeds right. However B does an interesting thing; unless the slow speed dial is on 1/30, when you take your finger off the shutter release, it'll run through the 1 second escapement or whatever you have it set to before closing the curtain. I can't remember if it always did this! I don't think it's right though.
I'm going to build a three-sensor shutter tester for my sound card during my lunch break today and that might give me a clearer picture (no CRTs at work either, ha). Focal plane shutters are a pain! I thought I was going to be in for a treat after fiddling with the microscopic springs and gears and levers in Compurs, but I wish I was dealing with a leaf shutter right now
Oh well, I suppose the frustration will pass when I understand what is going on.
Was a sunny day at the beach so took my new Yashica YF. After souping the shots, noticed that 1/1000 (which I've hardly used yet) was capping rather badly.
The YF is a Nicca 5L facelift, which in turn was basically a fancy Leica-M style body with screwmount innards. As far as I am aware, it's a pretty typical Barnack shutter, with the slow speeds on the front etc.
I read about shutter capping, and after doing the CRT shutter test I decided that the 2nd curtain did have too high a tension.
Pulled off bottom cover, looks like somebody has been in there before. The YF has these interesting ratchet and pawl adjusters for shutter curtain tension. I backed some tension off (way too much, curtain wouldn't run the whole way), then tightened it up. It stopped capping, but the speeds were too slow.
So I spent an hour or so fiddling around with the second curtain's tension. Here are the weird things that are happening now:
Sometimes the shutter doesn't release properly on 1/1000; you press shutter release, first curtain is released part way (maybe the gap at 1/1000?) and the shutter won't continue. It'll usually carry on once you take your finger off the shutter release. Before I touched the 2nd curtain tension, it'd do this occasionally on 1/30 - 1s. This problem seems to be OK now with the current curtain tension I have it set to (which is slow).
When I up the curtain tension slightly (I think), 1/1000 starts capping in a different way: instead of closing the gap towards the end of the shutter cycle (classic 2nd curtain too tight, right?), the "fade" is at the beginning of the cycle instead. Doesn't happen every time.
Do these two things point to a problem with the shutter release mechanism instead of curtain tension? Or do I need to start adjusting the first curtain too?
Last thing: right now I know the second curtain tension is too low. Shutter speeds look too "wide" on the CRT screen. This has affected (I assume this is the cause) the slow speeds: 1 second sounds more like 1.5 or 1.75s. Not too worried about that yet, until I get the fast speeds right. However B does an interesting thing; unless the slow speed dial is on 1/30, when you take your finger off the shutter release, it'll run through the 1 second escapement or whatever you have it set to before closing the curtain. I can't remember if it always did this! I don't think it's right though.
I'm going to build a three-sensor shutter tester for my sound card during my lunch break today and that might give me a clearer picture (no CRTs at work either, ha). Focal plane shutters are a pain! I thought I was going to be in for a treat after fiddling with the microscopic springs and gears and levers in Compurs, but I wish I was dealing with a leaf shutter right now
Oh well, I suppose the frustration will pass when I understand what is going on.mooge
Well-known
Wow. I've had capping problems with my Leica M2 that are similar to yours- 'fade' at the beginning of the exposure (left side of the photograph) that went away with adjusting tension or pressing the shutter release quickly. really weird. I also noticed that if I slowed the shutter travel (with a finger on the shutter drum)and pressed the shutter release, it would stick at the second curtain release point until I released the shutter button, then both blinds would travel to the end without a gap. This works best with the higher speeds and goes away at 1/60 or so.
My solution was just to add tension to the curtains- I intentionally set it up with low tension, but I guess I couldn't get away with that. I poked and prodded and flood cleaned and re-lubed and black magiced the mechanism, but only adding tension helped. so maybe it is a tension issue because my camera didn't have any issues when I got it (well... besides a bad shutter curtain).
a tip for setting curtain tension- clean and re-lube the slow speeds, add tension until they work spot-on. This makes sense in theory, assuming the factory set the escapement up correctly. I could be wrong...
good luck, please post if you find out what was wrong.
My solution was just to add tension to the curtains- I intentionally set it up with low tension, but I guess I couldn't get away with that. I poked and prodded and flood cleaned and re-lubed and black magiced the mechanism, but only adding tension helped. so maybe it is a tension issue because my camera didn't have any issues when I got it (well... besides a bad shutter curtain).
a tip for setting curtain tension- clean and re-lube the slow speeds, add tension until they work spot-on. This makes sense in theory, assuming the factory set the escapement up correctly. I could be wrong...
good luck, please post if you find out what was wrong.
xwhatsit
Well-known
G'day Dragunov, appreciate the reply and information. Sounds very similar to my problems.
Heartening to hear you solved the problem just with curtain tension and nothing more serious. Obviously I need to strip and clean the mechanism too, which I haven't done yet. Haven't had access through the top cover yet, as there's a nasty seized grub screw holding the shutter dial on that I still haven't got around to drilling out. Before I dove in and started pulling everything apart I wanted to see if I could fix it with just a simple adjustment to the second curtain. Perhaps a little different to the Rangefinder CLA culture but I prefer to strip and touch as little as possible, providing the camera is still as it left the factory. However I think a full-blown flood cleaning might perhaps be warranted in this case.
I finished building my shutter tester (took a little bit longer than lunch break, sssh, don't tell my boss!). Unfortunately it's only a two-sensor tester at this stage, couldn't find any more of the Omron 4235A optointerrupter thingies to pull apart. Plus my idea of combining the channels (sound card) for a third sensor wouldn't work, I think, at lower speeds.
I have two sensors 24mm apart (maybe 23.5mm). Shutter speeds are reading a little slow right now as I thought:
1/60 is about 1/50
1/125 is about 1/100
1/250 is about 1/150
1/500 is about 1/250 at the beginning of the cycle, and 1/220 at the end
1/1000 is about 1/700 at the beginning of the cycle and 1/500 at the end
So obviously tension needs to go up. Interesting the tapering that is going on -- gap starts out smaller and gets bigger. So second curtain tension should go up.
As for curtain speed across shutter, I'm getting on average about 14ms across the 24mm. This means I think I'm getting 21 ms across 36mm? Isn't 20ms supposedly the correct time for the curtains to move the 36mm? So not too far out.
Will start playing with curtain tensions again when I get home.
Heartening to hear you solved the problem just with curtain tension and nothing more serious. Obviously I need to strip and clean the mechanism too, which I haven't done yet. Haven't had access through the top cover yet, as there's a nasty seized grub screw holding the shutter dial on that I still haven't got around to drilling out. Before I dove in and started pulling everything apart I wanted to see if I could fix it with just a simple adjustment to the second curtain. Perhaps a little different to the Rangefinder CLA culture but I prefer to strip and touch as little as possible, providing the camera is still as it left the factory. However I think a full-blown flood cleaning might perhaps be warranted in this case.
I finished building my shutter tester (took a little bit longer than lunch break, sssh, don't tell my boss!). Unfortunately it's only a two-sensor tester at this stage, couldn't find any more of the Omron 4235A optointerrupter thingies to pull apart. Plus my idea of combining the channels (sound card) for a third sensor wouldn't work, I think, at lower speeds.
I have two sensors 24mm apart (maybe 23.5mm). Shutter speeds are reading a little slow right now as I thought:
1/60 is about 1/50
1/125 is about 1/100
1/250 is about 1/150
1/500 is about 1/250 at the beginning of the cycle, and 1/220 at the end
1/1000 is about 1/700 at the beginning of the cycle and 1/500 at the end
So obviously tension needs to go up. Interesting the tapering that is going on -- gap starts out smaller and gets bigger. So second curtain tension should go up.
As for curtain speed across shutter, I'm getting on average about 14ms across the 24mm. This means I think I'm getting 21 ms across 36mm? Isn't 20ms supposedly the correct time for the curtains to move the 36mm? So not too far out.
Will start playing with curtain tensions again when I get home.
martin_t
Established
Just curious, how do the results compare between the CRT and your shutter tester. Did the slit widths and fade you observed on the CRT roughly agree with the tester ?
xwhatsit
Well-known
I think so. Hard to tell because I find it difficult to ascertain the width of the `band' on the CRT screen accurately.
I think I saw the tapering (fast at beginning, slow at end) on the CRT screen as well with the faster speeds.
Still haven't got around to playing with the curtain tension yet.
I think I saw the tapering (fast at beginning, slow at end) on the CRT screen as well with the faster speeds.
Still haven't got around to playing with the curtain tension yet.