|Shutter tester and Kodak Retina IIc|
There is a light-sensitive phototransistor out on the end of the boom which is maneuvered in close to the rear lens. A flashlight is shone on the front of the lens and the shutter is tripped. The result is captured through a connection to the microphone port by the freeware Audacity sound recording/editing program.
|Audacity Sound Recording and Editing Program, Retina II results|
The dark block encloses the opening and closing points of the shutter on my Retina II and the length block at the bottom center shows the duration of the exposure to be 0.012 seconds. Divide 1 by that amount and you get a shutter speed of 1/83 with the shutter having been set to 1/100. When I set the Compur-Rapid shutter to 1/250 I got a recorded speed of 1/200. That is better performance than I get from my Retina IIa, and I was surprised and pleased because the Xenon lens on the II model is probably the best on any of my Retinas.
I tried out the tester on quite a few of my cameras. The Compur shutters produced very smooth wave forms and the results repeated consistently. The box camera results all showed speeds in the expected 1/30-1/40 range, but the wave forms were noisy and I didn't have a lot of confidence in the absolute numbers. Still, the comparisons are interesting, and the relative values are useful. I didn't try speeds above 1/250 as it seemed that would be stretching the device's capabilities beyond its potential accuracy.
Mid-way through my shutter testing, this mantis showed up on my front porch, so I snapped a few portraits with the digital: