23 thoughts on “Simple shutter speed tester

  1. “He plugs the circuit into some sound editing software to get the signal.”

    Heh, if only things were that simple.

  2. Too bad this won’t work via the optical viewfinder because the mirror is lifted prior to exposure.

    What’s a good way to do the same for a DLSR? A rotating disk and a fast strobo light?

  3. I doubt this works accurately at really high shutter speeds, where the finite pinhole size will probably blur out the signal. A few more real results would be great to evaluate the performance…

  4. You can test at very high shutter speeds by pointing it at any CRT television that is displaying static (doesn’t work with flatscreens, CRT only), and looking through when it fires. The ghost image left on good old Retina 1.0 will tell you all you need to know.

    Because of the CRT’s refresh rate, you can get different interference patterns depending on shutter speed, and even diagnose specific issues to each curtain based on the shape, angle and pattern of the ghost image left on your vision.

  5. @Claudio
    You could test do a similar test for DSLRs using a micro and LEDs. Have the micro trigger the camera, and strobe a multicolor LED, or several LEDs in a row. Would need to be rather accurately timed programing, but should get you a close for the lower side of the shutter’s capabilities.

    If you were pushed, you might be able to get a ribbon cable through the body at some location. Might even be able to concoct a small wireless device to squeeze behind the shutter over the sensor. If I ever get my hands on a busted DSLR, I will give this a try and see what I can cook up.

  6. I remember my Dad doing this about 30 years ago with a rather nifty little Vivitar camera (they used to be great) connected to an LDR. Worked perfectly and helped fix the camera to keep it going for another few years.

  7. @NatureTM

    Thanks, but not mine. That is something camera repairmen WAAAAAY back in the days before electronics figured out.
    You can try it yourself with a known good camera to get the idea of what different shutter speeds “look” like, or try to look it up online. I would hope there is a chart up somewhere, hopefully it isn’t just more lost tech at this point.

  8. @Claudio

    I found you the perfect DSLR tester – also an old TV. In this case, take a picture on the screen at any high shutter speed.
    As per an article in the Dec 1967 Popular Mechanics, you only need to count the number of visible lines in the shot. Each one represents exactly 1/15,750 second.
    The screen is interlaced and repeats each full screen of 525 lines every 1/30 of a second. 1/60 of a second gives you exactly half the screen visible in the snapshot, down to only 4 lines visible for 1/4000 sec and 8 lines for 1/2000. 15 lines equals 1/1050 sec.

    Pretty easy, eh?

  9. Thank you for the interest you show about my invention.

    I’ve used the tester with speeds up to 1/500 with good results.

    …And yes, there is still people using non-digital cameras.

    Pablo

  10. Instead of placing a special back with the sensors on it, couldn’t you just shine a bright lightsource into the lense, and then put a photoresistor against the viewfinder, hooked up to a microcontroller or computer to time how long the viewfinder goes ‘dark’? Would also work on DSLR cameras, I suppose.
    Or is there something against that method?

  11. No geert what happens in a SLR is that the mirror flips up and then the shutter opens, at a speed set in the camera’s settings, the shutter and the mirror are not the same thing and the mirror’s lag between pressing the button and flipping up will be constant (apart from changes due to temperature of course).
    So I’d advise to use that TV screen trick mentioned by others if you want to avoid using a custom back.

  12. I am one of the many people who has used this idea before, because if you searched the net it was an idea that readily came up in the search results.

    I have to point out that a single photodiode doesn’t give you enough information to accurantely measure the shutter’s performance for the real world. Because there are two different shutters in your average SLR (front and rear curtains released at different times) you need to ensure that they are moving at the same speed. Otherwise the image will get progressively more or less exposed as the two shutters move across the film plane. Two diodes placed at opposite sides of the film plane work very well. You can also measure the shutters’ total velocity which is important for a manual camera because the springs may become tired after many years, especially if you foolishly charged the shutter before putting the camera away in the cupboard for years ;-)

    @andrew: it really is that simple – for my soundcard anyway.

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