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#1
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Shutter timing
How can I go about timing the shutter speeds of my old shutters (Compurs,
Ilex, etc.)? Is there a technique and/or some inexpensive equipment to do this, or does this require an expert (and what can I expect to pay for such a service)? Thanks |
#2
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Shutter timing
In article , "st" wrote:
How can I go about timing the shutter speeds of my old shutters (Compurs, Ilex, etc.)? Is there a technique and/or some inexpensive equipment to do this, or does this require an expert (and what can I expect to pay for such a service)? Bob Monaghan's site has some good home-brew tips. Specifically, http://medfmt.8k.com/mf/shutterspeed.html A real shutter tester can run you around $550. A professional repair person is a good bet. |
#3
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Shutter timing
"jjs" wrote in message ... In article , "st" wrote: How can I go about timing the shutter speeds of my old shutters (Compurs, Ilex, etc.)? Is there a technique and/or some inexpensive equipment to do this, or does this require an expert (and what can I expect to pay for such a service)? Bob Monaghan's site has some good home-brew tips. Specifically, http://medfmt.8k.com/mf/shutterspeed.html I actually tried this: http://www.geocities.com/Yosemite/2131/shspeed.html and it really works well, I timed the 2 newest lenses I have and the readings are pretty accurate. Guillermo |
#4
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Shutter timing
sheesh ... if i could read schematic and get e clearer explanation I would do it ... Alex "f/256" wrote in message able.rogers.com... "jjs" wrote in message ... In article , "st" wrote: How can I go about timing the shutter speeds of my old shutters (Compurs, Ilex, etc.)? Is there a technique and/or some inexpensive equipment to do this, or does this require an expert (and what can I expect to pay for such a service)? Bob Monaghan's site has some good home-brew tips. Specifically, http://medfmt.8k.com/mf/shutterspeed.html I actually tried this: http://www.geocities.com/Yosemite/2131/shspeed.html and it really works well, I timed the 2 newest lenses I have and the readings are pretty accurate. Guillermo |
#5
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Shutter timing
"AArDvarK" wrote in message
news:Pzr4c.12289$Nj.5600@fed1read01... sheesh ... if i could read schematic and get e clearer explanation I would do it ... It's a simple DC voltage source and a phototransistor. It puts a DC voltage across your soundcard's mic jack, somewhat proportional to the illumination that falls on the phototransistor. It doesn't strike me as a particularly good way to do this, but simplicity has its advantages. The on-off transitions show as spikes in the otherwise flat recorded wave. A frequency domain plot would show the spikes more explicitly, and somewhat mask the uninteresting parasitic capacitance. A better, but more involved circuit would gate a 1 kHz tone onto the mic jack. The waveform envelope would better represent the shutter state as it opens and closes. But simple is good. You can also just record the noise your shutter makes, and guess at what the clicks and rattles mean. The extremely high circuit capacitance looks like it will be a liability for faster shutter speeds, but I reckon close enough is close enough. Also, take note that the waveform is clipped at audio volume extremes. It looks like a 10k or 22k current limiter would be more appropriate than his 5k. |
#6
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Shutter timing
In article Pzr4c.12289$Nj.5600@fed1read01, "AArDvarK"
wrote: sheesh ... if i could read schematic and get e clearer explanation I would do it ... [... snipped .. top posting is confusing ...] Bob's site has a couple good old analog methods, like using a turntable, TV, etc. No schematics neccessary. |
#7
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Shutter timing
jjs wrote:
In article , "st" wrote: How can I go about timing the shutter speeds of my old shutters (Compurs, Ilex, etc.)? Is there a technique and/or some inexpensive equipment to do this, or does this require an expert (and what can I expect to pay for such a service)? Bob Monaghan's site has some good home-brew tips. Specifically, http://medfmt.8k.com/mf/shutterspeed.html A real shutter tester can run you around $550. A professional repair person is a good bet. Calumet have a shutter speed tester. When I got mine, it was about $75. It might be a bit more now, but there is no reason for a think like that to cost $550 unless you are talking about spinning prism shutters for photographing nuclear explosions or something. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ Registered Machine 73926. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 8:00am up 13:07, 2 users, load average: 2.10, 2.11, 2.09 |
#8
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Shutter timing
Yep ... Catalog Item #: AA8075, $99.99. Alex "Jean-David Beyer" wrote in message ... jjs wrote: In article , "st" wrote: How can I go about timing the shutter speeds of my old shutters (Compurs, Ilex, etc.)? Is there a technique and/or some inexpensive equipment to do this, or does this require an expert (and what can I expect to pay for such a service)? Bob Monaghan's site has some good home-brew tips. Specifically, http://medfmt.8k.com/mf/shutterspeed.html A real shutter tester can run you around $550. A professional repair person is a good bet. Calumet have a shutter speed tester. When I got mine, it was about $75. It might be a bit more now, but there is no reason for a think like that to cost $550 unless you are talking about spinning prism shutters for photographing nuclear explosions or something. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ Registered Machine 73926. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 8:00am up 13:07, 2 users, load average: 2.10, 2.11, 2.09 |
#9
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Shutter timing
"st" wrote in message ... How can I go about timing the shutter speeds of my old shutters (Compurs, Ilex, etc.)? Is there a technique and/or some inexpensive equipment to do this, or does this require an expert (and what can I expect to pay for such a service)? Thanks Calumet sells a small shutter tester than works very well. I don't know the current price, it was about $80 US the last time I looked. This little box works well for all types of shutters including focal plane shutters and can also measure the duration of strobe flash. The calibrated times of a shutter are not the total open times, they are, rather, the _effective_ time for the full aperture of the shutter. The opening and closing times of the shutter leaves is constant for all speed settings to they have the most effect on the highest speed. For Compur shutters with a top speed of 1/400th or 1/500th second the opening and closing time is around 1/1000th total. Up to about 1/250th this has insignificant effect but both 1/400th and 1/500th will measure about 20% low on a total open time tester like the Calumet when the shutter is operating properly. The original specs for Synchro-Compur shutters are +/- 5% for speeds up to the top speed and +/- 20% for that one. Most used shutters will not be quite this good but will still be pretty accurate. Shutters need to be very clean to be consistent. Inconsistent shutters are usually the result of partial cleaning. Shutter blades must be free of any residue whatsoever if the shutter is to make its top speed. Lubrication, where its used, is very fine synthetic oil. Grease is used in very small amounts on the speed cam. Do NOT use powdered graphite on any shutter ever despite the occasional recommendation you will see for it. Its NEVER specified as an original lubricant and will gum up a shutter royally if used. -- --- Richard Knoppow Los Angeles, CA, USA |
#10
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Shutter timing
I looked into the suggested methods and found
that buying a "phototransistor" is going to be a wild goose chase. Radio shack came up empty and most other parts houses have minimun orders of $50 to $100 - forget it unless you have one to hand or a very good electronic junk store around the corner. Instead I just attached my microphome (any type) to my PC and recorded the sound in Sound Forge (Cool Edit, or Nero will work too). On slow speeds (1/2 or 1 sec) The shutter action is quite clear. By the time I got to 1/60 second it became much harder to determine where the open and close were. That's not too important. What I was able to determine was that the shutters I was testing were 1) consistent from one snap to the next 2) porportional - 1/2 second was about half of the one second and so forth. 3) Different from shutter to shutter. This last item is a puzzle. If I have two shutter+lens combinations and they both record the scene with the same approximate density at the same shutter speed and aperature (same film) but time differently in the above test, I can only conclude that the iris opening has been compensated since the exposures are near identical. Makes sense. Shutter timing is only half of the equation. How accurate is the iris ? Moral - your shutter doesn't have to time exactly. just give consistent and predictable exposures. |
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