I inherited this beautiful 1950 Rolleiflex camera from my father and my friend gave me his 1954 Heathkit oscilloscope. I am a newbie to this testing device and I would like suggestions on basic ways of using a 555 timer plus a phototransistor from a computer mouse to do a shutter speed test. I have read up a little on the designs and I find too many options and variables. The basic idea is to shine a bright light into the lens of the camera, set one of eight different shutter speeds, and release the shutter. When the light hits the sensor and when it stops should show on the scope. This is supposed to show the length of time the shutter was open for. I need some guidance for the simplest (not necessarily the best) set up that I can understand. I would appreciate any and all comments. Thank you, Greg