What exactly happens when you expose an image using a DSLR camera ? To illustrate the series of events which take place in that short “click” moment the image is taken, I borrowed a highspeed-video camera from work during lunch break and filmed my Nikon D300s without lens and my Zenza Bronica ETRS analog middle format camera.
The Olympus iSpeed camera I used can take up to 15.000 frames per second (fifteen thousand), which slows even the fastest events down to super-snail-slow-motion. Also with an exposure time of 1/15.000 sec you need a strong light source, which is provided by the super-bright lamp you see in the image above. Actually fifteen thousand frames per second slow the exposure cycle down so significantly, that the raising of the mirror took 40 seconds in the original video. The footage you see in the above video is played back at twelve times the normal rate !
I recorded the exposure cycle of my D300s at 1/125 sec, 1/2.000 sec and at 1/8.000 sec (without lens) to illustrate what happens. After that I filmed the communication between the internal flash of the D300s and a SB-900 speed light flash which is used in slave mode. Finally I filmed the exposure cycle of my Zenza Bronica ETRS camera with and without the lens attached.
It is interesting to see how the front and rear curtain form only a narrow slit when the exposure time is very short (1/2.000 sec and 1/8.000 sec). Also I was astonished to find out that the curtain in the Zenza Bronica is in the lens. Well, it’s quite obvious because there is no curtain in the body, but I never thought about that before, just used the camera.
Enjoy the video !