| Author |
Message |
    
Jfdupuis
Tinkerer
Username: Jfdupuis
Post Number: 4
Registered: 12-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 30, 2009 - 05:00 pm: | 
|
Hi,
I'm working on a synchro-compur shutter that goes on a 4x5. The shutter was a bit sticky at slow speed and I decided to clean the mechanism in methanol. The shutter now work great and but the speed are a bit off.
I spend few time trying to get them right but I'm not able to have them all right on. I can get the {1,2,5,10} group more or less close, but then the {25,50,100} group is then off. I can also do the opposite. Is there a trick to have them all right on spot ? What should be an acceptable tolerance on the opening time ?
Thanks,
Jeff |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 873
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 30, 2009 - 07:48 pm: |
|
Most of the time the speed adjustment is done by how you position the escapement module in the shutter when you put it back in: you loosen the screw at one end and slide the module either inward toward the lens or outward toward the edge. Different shutters vary in details, but in the Synchro Compur in the Retina IIa, the adjustment at the "clockwise" end of the escapement affects all speeds, and you move it inward to slow the speeds and outward to speed them up ... and the "counterclockwise" end affects only the slow speeds, and you move it in the opposite direction - inward to increase speed, outward to slow it down.
Measuring speeds on a leaf shutter is a bit tricky especially at the fastest speeds, because of the way the opening is constantly changing in size during the exposure - the effective speed at 1/500 will be different based on the aperture you have set. I would try to get the slower speeds up through 125 to within 1/2 stop if possible and then accept what you get at 250 and 500 as long as each is faster than the last. |
Jfdupuis
Tinkerer
Username: Jfdupuis
Post Number: 5
Registered: 12-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, May 01, 2009 - 01:22 am: |
|
Thanks Rick, that help a lot. Knowing how the movements of the escapement module affect the speed will be of great help. |
|
