[LargeFormat] Compur #1 and Copal #1 for G-Claron 305mm f9

[Clive Warren]

At 10:00 pm -0800 21/1/02, Frank Filippone wrote:
>Secrets on the Iris plate.......
>Let's assume you already have an iris plate, for a 210 lens.  A rather
>common lens for a Copal1 shutter.
>
>210mm = marked F stop
>240mm = +1/3 stop.. is, as marked,  F11 is 1/3 of the away from F11 towards
>F16.
>270mm = +2/3 stop
>305mm = +1 stop
>
>SO if you have that 210 Shutter, for an F5.6 or 6.3 lens, it is a rather
>easy change to just make a mental note to set the shutter 1 stop more open
>than the scene requires......F6.3 = Wide open, F9,  on a 305 lens.  Pretty
>neat?
>
>Rmemeber that just becuse the iris markings say the lens is at F5.6, this is
>not true for the G-Clarons.. the largest aperture POSSIBLE is F9.
>Pay no attention to the scales when they go bigger than  F9.
>
>My G-Clarons are all in standard Copal 1 Shutters... I just switch the
>elements, keeping the F-stop ring the same.  I use no shims.

Thanks for that Frank.

Unfortunately there are no Copal #1 shutters in the kit here so it 
will be a case of measuring the iris and making a small plate.

I will check out a couple of people locally though to see if they 
have Copal #1 shutters in their kit......

The main concern was the width of the shutter so perhaps if you get 
the chance you could measure it for me?

Sounds as though you use the 305mm - how do you like it and have you 
encountered any aberrations when using it at infinity wider than f22?

The lens will make my field outfit a little more manageable - the 
Kodak 12" Commercial in Ilex #4 is a tad large and heavy.  All I need 
now are two recessed lens boards for the MPP Mk VII - one will be 
used back to front for the 305mm.

Cheers,
        Clive