Testing accuracy of shutter speed
In the old days we used a turntable at 45 rpm, attached a white piece of chalk and calcuate the shutter speed from the white band it produced. While testing now a new camera in my pool – a Contax 645 – I thought about some similar method but with more present day technology. Could be acoustic (waveform analysis of the click noise) or optical (distance travelled by a moving object). There is a fancy method for large format that I found at photo.net
Basically using the large format lens shutter, at various speeds, and comparing the exposure to the DSLR set to the same speed, all while pointing the DSLR at the large format camera’s ground glass.
Another method uses an old TV screen or CRT computer monitor as shutter tester
For just checking speeds, it works with both focal plane and leaf type shutters. The quickest way to do it is to remove the lens and look at the screen through the camera as you fire the shutter; for cameras with fixed lenses you can put a piece of groundglass in the film plane and look at that.
Video analysis is also frequently suggested but limited if you don’t own a Phantom that’s good for 1000 fps. Some cameras can record 60 fps, which would show 1 open fame at 1/500s. But wait audio seems to be even easier:
I release the shutter button about half a second after the shutter closed so the sound of the auxilliary shutter is separated from the sound of the diaphragm shutter. I recorded each shutter speed three times in order to test if they vary from time to time …Then I read the file into the computer and opened it with Audacity.
Basically the same principle of an Iphone App. So I went for audio testing. My example show 1/250 basically starting at the 2nd peak.
Works perfect in the range 1/1000 to 8s.