rolleistef
Well-known
Hello all,
Here's a rather simple methos to check a shutter accuracy.
All you need is a microphone and a sound production software.
By recording the sound of the camera (works better with focal plane shutters and non-reflex camera in general, you get the graph of the sound, with time graduation.
First of all, you need to find out what sound you "see" on the graph.
There are five principal parts :
#1 : trigger being pressed and actuating the mechanisme
#2 : shutter opening, which is the big thing you see. The peak you see is the shutter blades "hitting" the sides when they have opened completely
#3 : that looks like a fish backbone! It is in fact the time during which the shutter is completely opened, and what you see is the clockwork whizzing.
#4 : shutter closing. The clockwork finishes its course and releases the shutter blades,
Which strike closed on #5.
The trigger being released is the peak at far right
What you need to take into account is the time between the beginning of the opening of the shutter and the end of the closing, since of course light will start writing on your film at the very moment when the shutter starts to open. If your microphone is really sensitive, you'll even be able to hear the mad sound of photons hitting the emulsion at C speed. No that's not true actually.
Picture 1 : 1 second on a Rolleiflex T, Synchro-Compur shutter
Starts opening at 1.995 and ends its closing at 2.885, which is 0.89 second. Not bad for a 50yo shutter that has never been CLAd!
Picture 2 : 1/8 of a second on a Hi-Matic 9, Seiko FLA shutter.
Starts opening at 4.012 and ends closing at 4.159, which is a 0.15 second time. 1/8th = 0.125 second, 0.15 is closer to 1/6th.
Of course you need to make your own tries but it seems to be relatively accurate down to 1/100th of a second.
Another methods, based on the same principle, uses a laser pointer and a photoeletric diod connected to a micro jack. The "sound" is produced but the cell, which, as a diod, will let allow electricity to pass when hit by light. Once the shutter is opening, the laser goes through the lens, light hit the cell which sends current to the recorder/computer, thus writing on a similar software the exact shutter time.
Hope that helps!
Here's a rather simple methos to check a shutter accuracy.
All you need is a microphone and a sound production software.
By recording the sound of the camera (works better with focal plane shutters and non-reflex camera in general, you get the graph of the sound, with time graduation.
First of all, you need to find out what sound you "see" on the graph.
There are five principal parts :
#1 : trigger being pressed and actuating the mechanisme
#2 : shutter opening, which is the big thing you see. The peak you see is the shutter blades "hitting" the sides when they have opened completely
#3 : that looks like a fish backbone! It is in fact the time during which the shutter is completely opened, and what you see is the clockwork whizzing.
#4 : shutter closing. The clockwork finishes its course and releases the shutter blades,
Which strike closed on #5.
The trigger being released is the peak at far right
What you need to take into account is the time between the beginning of the opening of the shutter and the end of the closing, since of course light will start writing on your film at the very moment when the shutter starts to open. If your microphone is really sensitive, you'll even be able to hear the mad sound of photons hitting the emulsion at C speed. No that's not true actually.
Picture 1 : 1 second on a Rolleiflex T, Synchro-Compur shutter
Starts opening at 1.995 and ends its closing at 2.885, which is 0.89 second. Not bad for a 50yo shutter that has never been CLAd!
Picture 2 : 1/8 of a second on a Hi-Matic 9, Seiko FLA shutter.
Starts opening at 4.012 and ends closing at 4.159, which is a 0.15 second time. 1/8th = 0.125 second, 0.15 is closer to 1/6th.
Of course you need to make your own tries but it seems to be relatively accurate down to 1/100th of a second.
Another methods, based on the same principle, uses a laser pointer and a photoeletric diod connected to a micro jack. The "sound" is produced but the cell, which, as a diod, will let allow electricity to pass when hit by light. Once the shutter is opening, the laser goes through the lens, light hit the cell which sends current to the recorder/computer, thus writing on a similar software the exact shutter time.
Hope that helps!
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