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02-01-2011, 08:59 PM   #1
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Dum leaf shutter lens question

I've been trying to figure out how these work...you connect the sync socket to the lens, cock the lens, but then how does the sync pulse release the lens mechanism? Does the lens need power on a few contacts to power some internal circuitry? Or is this all mechanical?

02-02-2011, 01:30 AM   #2
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Connect the flash to this socket.
First wind up the leaf-shutter. When the camera is fired the leaf-shutter is also released. He gives the sync-pulse to the flash.

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02-02-2011, 07:35 AM   #3
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I was wondering how the lens gave the sync pulse actually...no batteries or power to the lens afaik, so it should be all mechanical.

Wheatfield had a good description of the rest of the operation:
"The sequence for the leaf shutter operation is:
When the camera shutter is tripped, the aperture lever trips the leaf shutter. The leaf shutter closes as the aperture stops down. The camera shutter opens, and during this time, the leaf shutter opens and closes. The camera shutter then closes and the leaf shutter opens again as the aperture lever is released.
This is why it is important to only use the leaf shutter with a camera shutter speed of 1/8 second. Everything is timed around that camera shutter speed. Apparently things can break if a different camera shutter speed is used during leaf shutter operation."
02-02-2011, 08:23 AM   #4
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QuoteOriginally posted by kenyee Quote
I was wondering how the lens gave the sync pulse actually...no batteries or power to the lens afaik, so it should be all mechanical.

The mechanism that fires the flash is purely mechanical. It is just a microswitch.
Everything else is done by the flash.
If you want to see, take a flash that has a sync cord and touch a pencil point to connect the contacts that plug into the camera.
The flash will fire.

02-02-2011, 08:49 AM   #5
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I once inadvertently had the camera's shutter on 1/4 on a 6x7 with a LS lens and ended up with about 1/3 of the frame unexposed.
02-02-2011, 03:42 PM   #6
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QuoteOriginally posted by Wheatfield Quote
The mechanism that fires the flash is purely mechanical. It is just a microswitch.
Thanks Wheatfield...makes sense...I've used a paper clip to fire a flash on a pc sync cord before. Was trying to figure out if there was some way to get a 645 LS lens to fire on a K body...
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