Posted by Les on April 13, 2001 at 12:59:20:
In Reply to: Using Modern Flash posted by Michael Funkhouser on April 13, 2001 at 08:39:40:Okay you are facing two problems, the most difficult to overcome may be solved already.
BAck in the days of the Flashbulb, The shutter was delayed in opening for about 1/5th of a second (20milisceonds) to give the flashbulb time to warm up. This is called M sync and modern flash equipment won't work, or will work very poorly on M sync. This is also true with solenoids.
the reason is most of the electronic flash's light is done and over with before the shutter opens, thus it won't matter what shutter speed you set it at.
The other option is to not tie the flash to the lens but open the lens, flash the flash manually and then close the flash.
Now if your Compur shutter has an X sync then ignore all of the above, since electronic flash uses X sync.
rumage around and find the manual for your flash and find the guide number. Usually the guide numbers are for ISO 100 film. email me off list for guide numbers other than iso 100.
Let's assume that the guide number is 160. Set the shutter for something reasonable like 1/60, use the rangefinder/ground glas to focus and then read what the distance is between you and the subject( on the distance scale on the bed of the camera). Let's say it's 10 feet. Uh oh here come some math:
Divide the distance into the guide number and you will get the aperture.
160/10=f16
Notice if we double the distance we open up one stop
160/20=f8.
One of the old timers tricks is to do the math on a piece of paper for common distances say 6 8 10 12 16 20 feet, then tape over the distance scale or sit the tape next to it and write down the apertures. That way you focus, look down at the tape and read the aperture for that distance. Saves a lot of time.
Les