A quick way to test your shutter speeds

Discussion in 'Exposure Discussion' started by Krzys, Jul 16, 2010.

  1. Krzys

    Krzys Member

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    After seeing many ads over time saying 'the slower speeds may be off' I thought I should share a simple trick I use for examining shutter speed problems.

    Download a small and free audio recording program like Audacity or Reaper and use a computer mic to record the shutter. For at least the slow speeds you should be able to zoom in and see how long the shutter opens and closes, with the buzzing in between.

    I don't know how many other people do this but it works for me. Not super accurate but better than 'eyeballing'/listening for it.
     
  2. Ian Grant

    Ian Grant Subscriber

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    Yes, I did the same last year for my LF lenses and was rather suprised that the older Compur lenses were the most accurate.

    Ian
     
  3. Kevin Caulfield

    Kevin Caulfield Subscriber

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    And it's probably almost as accurate as many of the other methods.
     
  4. steven_e007

    steven_e007 Member

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    There's a thread on the LargeFormat forum about this that has got quite... involved :surprised:

    But basically... you can plug a simple phototransistor into your sound card and use Audacity to measure the shutter speed that way, too. It's accuracy is limited to about 1/200s at best - after that it can't measure shutters very accurately at all. Neither is it very good with focal plane shutters.

    Unless... you add just a little more electronics and place a pinhole over your phototransistor. It can then reasonably good for up to 1/1000s (and as slow as you like) even on focalplane shutters (well... big ones :wink: )
     
  5. SMBooth

    SMBooth Member

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    Beauty my Ilex #3 in slow by a stop.....but one copal is good, have to check the other one now. I was going to build (and I still might) the simple
    phototransistor one here (http://www.rusted.free.fr/speed tester.html)
     
  6. Slixtiesix

    Slixtiesix Subscriber

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    The easiest way for me is simply to put in a roll of Velvia and to go through all the speeds at the same EV. If all slides are exposed consistently everything is fine for me. Velvia does show even minute variations in exposure if you have a close look at the slides. I must admit that I do not have many cameras or leaf shutter lenses. Otherwise this would be a method too expensive for sure...
     
  7. Marco B

    Marco B Member

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    Good tip, thanks for sharing, I already have Audacity installed, but never thought of this.
     
  8. fdisilvestro

    fdisilvestro Member

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    Another way to do a shutter speed test involves the use of a D***l camera. You will have to place the lens/camera to be tested front to front with the d****l camera (like if they were kissing) You may use just black tape to avoid light leaks or use a combination of adapters and reverse mount adapters.

    The area on the back of the lens/camera to be tested should be lit by a constant and even light source

    This method assumes that a recent or new d***l camera with an electronic controlled shutter will be accurate

    Here is the procedure:

    The lens in the d**l camera should be on manual, constant aperture, constant ISO

    - First put the lens to be tested open and make an exposure with the d***l camera at the speed or speeds you want to test

    - Look at the histogram, you should see a narrow band at some point. You can adjust where the band should be either with ISO or the d****l camera lens aperture

    - Now, cock the shutter to be tested and open the shutter in the d****l camera on B. Release the shutter to be tested

    - Check the histogram and compare with the previous histogram. You would be able to tell if the shutter is accurate or how much it is off.

    - You can also use this procedure to check the effect of high shutter speeds whit small apertures in central shutter or to check if the diaphragm is properly closing before the shutter.

    Regards
     
  9. Jeff Kubach

    Jeff Kubach Member

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    Thanks for information, very useful!

    Jeff
     
  10. AshenLight

    AshenLight Member

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    This is a great way to test shutter speeds. Just a note though, Reaper isn't free except for evaluation. It's an amazing audio recording platform so if you decide to keep it and/or use it for recording, please support Justin and buy a personal license.

    Thanks and regards,
    Ash
     
  11. Slixtiesix

    Slixtiesix Subscriber

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    By the way, if you have a Mac computer than the easiest way is simply to use GarageBand for this. You can check at least 1 second and 1/2 second with this programm. Works pretty well. Just checked my Rolleiflex T and the SL66. Rolleiflex T: 1 sec is 1,5 sec in reality, 1/2 sec is 0,75 sec :-(
    Okay, I already knew that the shutter didnĀ“t work properly...
    SL66 however works fine. Hey, but she had just been serviced last year ;-)

    Best Regards, Benjamin
     
  12. benjiboy

    benjiboy Subscriber

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    When you,'ve tested your shutter speeds and assumint your test is accurate how do you know what margin of error is acceptable and still be within tolerance ?, because no shutter is absolutely accurate,.
     
    Last edited by a moderator: Aug 18, 2010
  13. BetterSense

    BetterSense Member

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    A couple points....

    This method only compares your shutter to the digital camera shutter. Its usefulness depends on the digital camera's shutter being accurate. I assume digital cameras have electronic shutters that are very accurate, but who knows. I know digital camera ISO ratings don't match what you will get with a good handheld meter; I wouldn't put it past camera manufacturers to have offset shutter speeds for some reason.

    Second, you might be tempted to use a similar method to check or adjust lens aperture scales. Keep in mind if you do this, you will be correcting for lens absorbtion, haze, and filter factor, and you will really be getting something like T-stops rather than F/stops. Depending on how much you value accurate DOF calculations compared to accurate exposure calculations, and how diverse your lens collection is, this could be a good or bad thing.
     
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  15. Rudeofus

    Rudeofus Subscriber

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    Sure, but a shutter that's 1% off won't affect image brightness in any appreciable way, whereas 50% is already half a stop. If you know how inaccurate your shutter is and you can verify that its offset is reproducible (i.e. not random), you can even compensate while shooting.
     
  16. jamesgignac

    jamesgignac Member

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    Krzys,

    Thanks for the tip, very useful indeed! I've used several cameras where I knew (only from seeing the end results) that the shutter speeds were off but now I'll know how far off :smile:

    I'm going to be buying a new MF setup sometime soon now that I've moved my base to China and chances are I'll be buying used...maybe I'll bring my laptop along for the ride!
     
  17. BetterSense

    BetterSense Member

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    50% SLOW is half a stop. 50% FAST is one whole stop.
     
  18. bobwysiwyg

    bobwysiwyg Subscriber

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    Sorry for the silly question, but I don't follow this??
     
  19. declark

    declark Subscriber

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    For my Rolleiflex and Hasselblad I used a digicam in video mode at 30 fps, then I just count frames right on the digicam. Works for the slower speeds up to ~1/30s. Open up the aperture of lens being tested, aim at bright object, press record, fire shutter, count frames in slow-mo playback. Super easy to do, but may not be stringent enough of a test, but then if the slower speeds are good, the faster ones are probably OK too.
     
  20. Q.G.

    Q.G. Inactive

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    That's the trouble with percentages.
    It's better to think in the usual terms of duration, and factors thereof.
    And then too to say what you mean, more, or less.

    50% slow means 50% longer, i.e. half as long again, than it should be.
    Twice as long, i.e. 1 stop, is 100% longer, or if you wish 100% slower.
    (50% slow however isn't half a stop, but 0.4 stop)

    50% fast means 50% shorter than it should be, i.e. 2x faster. And that's one stop.

    So just saying that "50% is already half a stop" isn't enough. Nor is it correct.
     
  21. RalphLambrecht

    RalphLambrecht Subscriber

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    Krzys

    That's a great method, and I have used it many times. I also have a Calumet Shutter Tester, which is unfortunately not available anymore, and used right, the audacity method in combination with the right detection hardware is more accurate, because it can records more cycles per second. Attached is a test of the 1/500s setting on a Nikon.
     

    Attached Files:

  22. RalphLambrecht

    RalphLambrecht Subscriber

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    This depends on what materials you use it for (B&W, slide, color) and what you are willing to accept, but there is a standard for shutter speeds and it is rather liberal.

    I use the following for B&W materials:
     

    Attached Files:

  23. fdisilvestro

    fdisilvestro Member

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    Agreed, I stated that assumption.

    No question about your point. I was reffering to problems like sticky diaphragm (happened to me) where the shutter will complete its cycle before the diaphragm closed, resulting in several stops overexposure (depends on the aperture settings)
     
  24. benjiboy

    benjiboy Subscriber

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    The way I look at it is that for me there's no point in my trying to check my shutter speeds because if they are inaccurate I don't know how to correct them, so I might as well leave it to a professional who does.
     
  25. Q.G.

    Q.G. Inactive

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    It makes sense though to test shutters yourself.
    Even if a professional repairman would test for free, you would have to go to, or send the equipment to, him before you even know whether there is something else for him to do also.
    If however you can test the shutter yourself, without too much trouble... no need for all that.
     
  26. RalphLambrecht

    RalphLambrecht Subscriber

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    You can correct for exposure deviations caused by incorrect but consistent shutter speeds through compensating aperture changes.