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Mszargar
Tinkerer
Username: Mszargar
Post Number: 1
Registered: 08-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 28, 2012 - 10:24 pm: | 
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Hello,
I have just bought a 1966 Zorki 4, and since I don't have a CRT monitor at home, I have tried to test the shutter speeds using Audacity audio recorder, measuring the time between the first sound peak related to shutter opening and the first sound peak related to shutter closing (fpofpc). For faster speeds I have measured the time between the last audio peak related to opening and the first audio peak related to closing as well (lpofpc).
These are the results all in milliseconds:
Speed Indicator (Correct Speed) : fpofpc (lpofpc)
1 (1000) : 680
2 (500) : 360
4 (250) : 206
8 (125) : 134
15 (62.5) : 77
30 (31.3) : 43.8 (41.3)
60 (15.6) : 21.65 (19.15)
125 (7.8) : 6.7 (5.9)
Obviously for 250 and above this method is useless.
I know this is not an accurate method, but do you think these are acceptable results for this camera, given that I will never really use any speed below 15? Is there anything I can do to improve the accuracy of the shutter?
Thanks in advance... |
Pailes
Tinkerer
Username: Pailes
Post Number: 7
Registered: 07-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 29, 2012 - 12:20 pm: |
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As long as you are shooting C41 or B/W film just overexpose 1 f-stop and everything will be fine. Negative film is very forgiving. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1228
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 01, 2012 - 03:12 pm: |
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There is some facility for adjustment of the slow speeds (1-15 and 60), but I think your point about how often you will use these speeds, and even more, how important critical accuracy is at these speeds, is very much on the mark. The faster speeds are more important, and there is no relation between the fast and slow control systems in the Zorki. You do not need any speed to exactly correspond to its theoretical duration. What you do need is, first and foremost, for the 2 curtains to be traveling at the same velocity, and secondly, for the speeds to step in a reasonable approximation of a 1-stop sequence from each setting to the next. I see that you're already familiar with the CRT tester method at http://rick_oleson.tripod.com/index-135.html . Although it does not give a numerical readout, it is very precise. Leica used to provide their technicians with a mechanical shutter tester that worked in exactly this way. A small black & white TV picked up cheaply at a flea market is a good investment as a shutter tester, even though it's now quite useless as a television. |
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