Shutter Curtain Action

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Can anyone explain the shutter curtain movements for this camera? In particular, I'm interested in the sequence and direction of the curtains. I have some handheld slides taken at slow speeds that I'm trying to figure out why they are softer on the left side than the right. SR

-- Steve Rasmussen (srasmuss@flash.net), December 16, 2000

Answers

Thanks for the outstanding responses! My experience with handholding the various lenses is as follows. The 45mm through 150mm seem to be fairly easy to handhold at slow speeds but the 200 and 300 are much more difficult to get sharp shots even when using faster speeds. But, the 400 and 600 can be shot at 1/125 and 1/250 respectivly and be sharper than the 300 at 1/125. Mass really does make a difference! SR

-- Steve Rasmussen (srasmuss@flash.net), December 17, 2000.

Typical focal plane shutter with cocked curtains on the left. At exposure the first curtain is released travelling to the right which opens the light path. That's followed by the second curtain which closes the light path. The gate is fully open for varying intervals at speeds of 1/30th second and longer. At higher speeds it's just a slit traveling across the gate.

-- Garrett Adams (gadams@jps.net), December 16, 2000.

Steve, as Garret explained, with times shorter than 1/30 sec, the first shuttercurtain is followed by the closing second curtain before it has arrived at the right side of the picture. The net effect beiing a slit of variing length (1/60 sec: 1/2 frame width, 1/125: 1/4 frame, 1/250 sec: 1/8 frame width etc.) travelling (and exposing) from left to right in 1/30 sec. That means that the right side of the picture is aproximateiy 1/30 sec later exposed than the left side. With handholding that time difference can cause the right side to be sharper because the residual vibration from the mirror and/or tripping the shutter has had time (1/30 sec) to die out.On a tripod with MLU the reverse occurs: the arrival of the first shuttercurtain at the right side of the picture causes vibration and the right side to be unsharp at 1/60 sec (at 1/30 and slower the left side is also less sharp, at 1/125 and shorter the unsharp area is 1/4 width or less at the right side, generally causing little trouble (also shorter exposure time). Greetings, Leen

-- Leen van de Klippe (leenvdklippe@hetnet.nl), December 16, 2000.

I have had the same experiences, and can fully agree with Leen - a very good explanation. It seems like the problem are smaller with the new 67II comparing to the old 6x7

-- Bert Wiklund (BWfoto@vip.cybercity.dk), December 17, 2000.

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