Could you please be more specific (setup, schematic) about your electronic tester, in both modes: time and pulses, and what precisely you saw or measured that made you think of a "capacitor holding a charge". Reason I'm asking is most simple circuits for shutter timing that are floating around require some caution in using the results, at least IMO.I used the electronically-tested numbers last weekend as-is, and when I came home with doubts I tried setting up my electronic tester to count pulses instead of time. In pulse mode (light interrupted by a fan), my electronic counter acted like there was a dwell, as if a capacitor was holding a charge...
Could you please be more specific (setup, schematic) about your electronic tester, in both modes: time and pulses, and what precisely you saw or measured that made you think of a "capacitor holding a charge". Reason I'm asking is most simple circuits for shutter timing that are floating around require some caution in using the results, at least IMO.
BTW, I have a Retina I with the shutter part dis-assembled since x months, when I gave up adjusting all speeds; but maybe I should have settled for +/-20%...
What are you using your shutter speed check to accomplish?
I ask, because if you are using it to check the accuracy of your exposure calculations, the way that leaf shutters work may screw up the calculation.
They take time to open, and take time to close. And that affects the resulting total exposure in a different way than with focal plane shutters.
I would expect certain parts of the image forms as a part of your "vinyl" shutter speed tester to show those effects.
Bill, since I've been restoring these old 78 radio/phonographs for the last 17 years, I can tell you one of the standard items I have to address is to send the rubber drive tire off for re-rubbering. These things are not running at correct speed. I doubt they're running a true 78rpm even after I'm finished with the restoration.
taking some of the Retinas apart can be difficult...
So I had a hunch the exposure method would throw in a wrench...
1.0 LogE from metered point to speed point (0.10) is for approximately 12% but my target was 18% gray.
So I shifted my shutter speed estimates 1/2 stop towards being faster speeds.
And you thought there was no practical use for knowing the trivia about 18% gray cards...
Also I said the rotational speed was a sanity check. You can see from the photo... There's no denying... at 1/25 the rotation in degrees is extremely clear. Shutter speed is really 1/20.
I made up a new cheat sheet for the camera where I use Exposure-based high speeds, rotational-based medium speeds, and electronic-based slow speeds.
As you can see, no one method (as I've implemented) works effectively for all speeds - but the entire set work together well.
500 = 1/160 (exposure-based)
250 = 1/100 (exposure-based)
100 = 1/70 (exposure-based)
50 = 1/35 (exposure and rotation agree)
25 = 1/20 (rotation-based)
10 = 1/7 (rotation-based)
5 = 1/3 (rotation and electronic agree)
2 = 3/4 (electronic)
1 = 1 (electronic)
As upsetting as it is to accept, ... I've come up with equally dismal results. So I can [sort of] concur. Evidence the shutter is in bad need of CLA. And even then I doubt the speeds could come up to actual marked speeds and stay that way for more than a year. ... But I also believe his numbers are the sad truth.
...I know Bill is disappointed at these numbers, because I've been there. But I also believe his numbers are the sad truth.
Thanks Tom1956, I think you'll understand I'm not disappointed at all... I've got shutter speeds I can use.
It's interesting how far the speeds are from nominal, which illustrates the often-heard expression: your light meter is probably the most accurate piece of equipment you have.
It's also a good learning experience for me... Now I know how to verify shutters of any camera, and this will help me when it comes to interpreting other people's Zone System tests... Because the Zone System calibration is designed to incorporate shutter speed variations in the personal EI. I now understand some people may "correctly" arrive at an EI that is higher than rated speed.
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