[LargeFormat] Wollensak Rapax Shutter

[Timothy Atherton]

Richard,

not specifically related to your post, but have you checked out this
treasure trove (frequently added to)?

http://www.cameraeccentric.com/html/info.html

Can't recall if I've posted it previously


tim a

> -----Original Message-----
> From: largeformat-bounces at f32.net [mailto:largeformat-bounces at f32.net]On
> Behalf Of Richard Knoppow
> Sent: November 18, 2005 4:17 PM
> To: f32 Large Format Photography Mail List
> Subject: [LargeFormat] Wollensak Rapax Shutter
>
>
>   Until the other day I thought the Rapax, also sold as the
> Graphex, originated after WW-2. It turns out that it
> probably was first made about 1942 or 43, not long after the
> Kodak Supermatic. The first Rapax/Graphex shutters evidently
> had brushed chrome faceplates rather than the black ones
> familiar to me. Graphex was a trade name used by Folmer
> Graflex for shutters sold on Speed Graphic cameras. From the
> advertising I just noticed the first shutters were the small
> sized ones used for 101mm lenses.
>    I wonder if anyone on this list has one or has seen one.
> At the time this shutter first came out Wollensak was still
> using Velostigmat as the trade name for its best lenses.
> Like Ektar, Velostigmat, and the later Raptar, specified a
> quality of lens rather than a generic type.
>    Rapax/Graphex shutters are good ones. Their advantage
> over the Supermatic and Compur is that the force necessary
> to trip the shutter is low and constant at all speeds. This
> is important where a solenoid is used for flash
> synchronization. Both the Supermatic and Compur require
> rather higher pressure for tripping at the highest speed.
> Unless booster batteries are used the solenoid may not trip
> them at all at this speed. Also, the pressure is great
> enough even at slower speeds to cause unreliable operation
> of the solenoid unless either an extra battery is used or
> one uses the special higher voltage dry cells sold at the
> time for photo-flash use.
>    I am especially curious if anyone has both the
> Velostigmat and Raptar/Optar versions of the lenses sold for
> Speed Graphic use. My experiencew with post war Raptar
> lenses is that they have a design flaw resulting is blurry
> images in the corners and margins even when stopped down to
> minimum despite being very sharp in the center. I am
> wondering if the design of the lens was changed c.1946 or if
> the older versions also have this problem.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk at ix.netcom.com
>
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