Testing Shutter speeds

Discussion in '35mm Cameras and Accessories' started by Matt5791, Nov 30, 2005.

  1. Matt5791

    Matt5791 Subscriber

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    Anyone know of the best way fo doing this - is there a device available?

    I have a Nikon FE2 I have just bought which I am suspicious about the shutter speeds, especially the faster ones. There is a definite difference when I fire it simultaneously with another FE2 I have that I know woks well.

    Thanks for any advice,

    Matt
     
  2. Lee L

    Lee L Member

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    http://www.davidrichert.com/sound_card_shutter_tester.htm

    Has an inexpensive DIY solution that should be accurate enough. You need a computer with a sound card, some free software, and a few electronics parts. Been hoping to make one myself, but haven't been able to set aside time for it.

    Lee
     
  3. Andre R. de Avillez

    Andre R. de Avillez Member

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    I've built this tester with a cigar box and "close enough" parts from Radio Shack. I used an IR sensor, which is all that Radio shack has, a single AA battery holder, and no On/off switch. I take the battery out and leave it in the cigar box until the next use...

    Let me know if I can help in anyway.

    André
     
  4. blumesan

    blumesan Member

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    Had a look at the description of this tester. Very clever and simple design but one big drawback. There is no way it will work for focal plane shutters at speeds faster than the flash synch speed. For such speeds the exposure is determined by a combination of the transit time and the slit width. And when the shutter speeds begin to go off it is always the faster speeds that are most affected.

    Mike.
     
  5. Curt

    Curt Subscriber

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    The Calumet shutter tester will test focal plane shutters.
     
  6. Lee L

    Lee L Member

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    The sound card tester will work for focal plane shutters and with faster speeds. The tester as built will show you how long the phototransistor is exposed to light, which is the same amount of time that piece of film would be exposed. I'm not up on the modern 1/8000 second shutters, but the traditional focal plane shutters I'm aware of travel at a single constant speed with only the slit width varied for speed adjustment. That's the very reason you need an electronic flash sync speed in which the whole frame is exposed at once. See this page for a shutter tester from a reputable mfgr that relies on this geometry: http://www.skgrimes.com/idcc/

    In any case the sound card shutter tester will be good for any speed at which the curtain spacing is equal to or larger than the diameter of the phototransistor sensor. Draw a circle on paper to represent the sensor and run two paper curtains over it at varying spacing to demonstrate this for yourself. Even with the sensor somewhat larger than the curtain spacing, you could measure the time between the two points halfway from min to max signal amplitude (halfway up the signal skirts) and get a good reading for shutter speed.

    Lee
     
  7. John Koehrer

    John Koehrer Subscriber

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    check with microtools, they used to have a tester for less than $100.
     
  8. Matt5791

    Matt5791 Subscriber

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    Mabey I should just send it to a repair guy and have a full service while he is at it!

    Matt
     
  9. blumesan

    blumesan Member

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    Said another way: The phototransistor sensor would need to have a sensing diameter (field of view) equal to or smaller than the narrowest slit width. It is my impression that the generally available sensors have a fairly wide diameter (angle of acceptance). If my assumption is correct then the described method will not work

    Mike.
     
  10. Curt

    Curt Subscriber

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    Unless you would like another project, get the Calumet tester, then you will have it for future checks. You can easily sell it too.
     
  11. Lee L

    Lee L Member

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    Regardless of sensor size, if you measure the time between half-max output and half max output of the sound card signal, you'll still get a reasonably good reading. It would only reach some percentage of potential max output, let's say 5% for example, so your shutter speed would be the time between 2.5% max potential beginning and ending outputs from the sensor. What you're assuming is that an aperture/slit covering only part of the sensor will drive the sensor output to zero, which isn't correct.

    Lee