Shutter how do you do the test

gunsmithing

gunsmithing

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I have test shutters with clocks, lathe and motor just by taking a photo this is not hard to do. Most motor on no load run at 1800 or 3600 rpm does good job for high speeds. I was telling a member early this month on how to do this check. for slow speed check I use a lathe on slow speed it to has a known rpm. Clock is same way. Use a bright light a flash will NOT WORK

The other way for lower speed is to use a digital cam record and fast speed and take movie of the shutter opening and closing. Not as good as the photo speed check but cheeper

Dave


[Some data is off the
http://tech.groups.yahoo.com/group/c.../message/30439
If you can find a 78 rpm record player and record, your problem would be solved by seeing how many degrees a white line from the center point of the record traveled while the shutter was open.]
 
I have always used a slide film and different combinations of aperture and shutter speed. ;)
 
I made a shutter speed tester using photo cells and a sound program called audacity.
Complete waste of time unless you know how to adjust the speeds on your camera!
I check Leica slow speeds by ear and high speeds by old crt TV on white noise chanel.
 
Another way is to suspend the camera over a record turntable. Put a thin white line (masking tape, for example) from the centre to the edge of the turntable and shine a bright light on the line. I found that this would work for leaf shutters as well as focal plane shutters.
 
Flashlight at the front, one of those digital audio toslink connectors feeding into a TORX-somthing receiver and a digital oscilloscope.

But like Nobbylon said: complete waste of time if you don't know how to adjust it.
 
nobbylon said:
Complete waste of time unless you know how to adjust the speeds on your camera!
Click to expand...

Properly adjust, too! Don't join the school of inept repairmen that try to fix slow shutters by blindly increasing torque (spring tension), or you'll kill your shutters.

Personally I think you should first of all own a service manual for every camera you try to adjust.
 
Any method using audio is problematic. Think about testing a press camera focal plane shutter, like a Speed Graphic. At what part of the audio waveform represents the period of time when the slit is scanning the film? You can't tell, especially considering it's a narrow slit scanning a wide sheet of film. The sound made by the curtain shutter mechanism is independant of the width of the slit. It sounds like a retractable window shade being released, that's all.

With these types of shutters you have to use an optical method.

I've found you can use a glass-encapsulated diode and an oscilloscope, or hack an old VCR tape end sensor, with a battery and resistor to bias the device.

I have a working Victrola, I'll have to try the 78rpm phono method.

~Joe
 
I use an old Arrowin tester :

http://www.flickr.com/photos/29504544@N08/6950232829/

6950232829_48f43da4cb.jpg


Great for 35mm cameras. A bit less for bigger as i have no MF sensor head and have to use masks to fit the 35mm format head on a 6x6 or 6x9 camera.
 
rodinal said:
see this...
Click to expand...

Indeed, i was considering something similar and nice to see that you allready realised it :)

Guess, with a graphic display it would be even possible to show a graph of the lightstrength.

btw Did you ever experiment with a slit mask before the sensorhead ?
I observed that all the 6 sensors in the testhead of my Arrowin are behind slits. Guess that this must be to improve accuracy.
 
nobbylon said:
...
Complete waste of time unless you know how to adjust the speeds on your camera! ...
Click to expand...

Not at all!

Back in the day, I had access to a good tester (a friend range a professional repair shop) and would periodically test my old mechanical shutters. If they ran consistently, I would simply note what actual speed was associated with each marked speed. I could then compensate when setting the shutter after taking a meter reading. In fact, I had a small table on my view camera lens boards that showed "marked" and "actual".
 
hanskerensky said:
btw Did you ever experiment with a slit mask before the sensorhead ?
I observed that all the 6 sensors in the testhead of my Arrowin are behind slits. Guess that this must be to improve accuracy.
Click to expand...

Never tried, but for sure it's to improve accuracy as you say. There are two factors that suggest this will not improve much the setup I used: the light source is a laser diode, so the light beam is very thin and sharp already, second, the light sensor (a phototransistor) has a built in lens, so it's very direction sensitive. But I think I have homework for the next weekend...

M.
 
Just try this shutter test work great simple to build.
Screen was good after find out how to use the software
Try out on a Pearl Rive S4 and ever setting speed was right.
This work great down to 1/8 sec shutter speed the slower shutter speed the hard to read the recording (too long of reading)
I use one Cadmium Sulfide and just a phone plug Radio Shack 276-1657

Dave

This one looks to be the best and very low cost
http://lalob.info/?page_id=66
http://lalob.info/?page_id=69
http://lalob.info/?page_id=72

This show how to better but the mic jack is hard to make
http://www.davidrichert.com/sound_ca...ter_tester.htm

Software for both
http://audacity.sourceforge.net/download/windows

Dave
 
rodinal said:
Never tried, but for sure it's to improve accuracy as you say. There are two factors that suggest this will not improve much the setup I used: the light source is a laser diode, so the light beam is very thin and sharp already, second, the light sensor (a phototransistor) has a built in lens, so it's very direction sensitive. But I think I have homework for the next weekend...

M.
Click to expand...

Yes, guess that with your setup a slit mask might not contribute anything.
My Arrowin has a very large surface lighted from behind with a DC halogen lamp set-up. This is done because the Arrowin also enables check of the real exposure values.
 
I use a window work great for high speed for the slow speed (1/4 sec) I think a CFL will work better to read the speed

Dave

hanskerensky said:
Yes, guess that with your setup a slit mask might not contribute anything.
My Arrowin has a very large surface lighted from behind with a DC halogen lamp set-up. This is done because the Arrowin also enables check of the real exposure values.
Click to expand...
 
hanskerensky said:
I use an old Arrowin tester :

http://www.flickr.com/photos/29504544@N08/6950232829/

6950232829_48f43da4cb.jpg


Great for 35mm cameras. A bit less for bigger as i have no MF sensor head and have to use masks to fit the 35mm format head on a 6x6 or 6x9 camera.
Click to expand...
You have such cool stuff, Hans. I still can't get over your old Voigtlaender collimator you picked up. Whatever will we see next! But you put it to good use. ;)
Cheers
Brett
 
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