[LargeFormat] Rodenstock Sironar 180mm f5.6 - Convertible

[Karl Wolz]

Clive,

Remove the front element.  Focus the camera on a near-infinity object, and
measure the distance from the lensboard to the groundglass.  Or if the lens
is not mounted, simply use a white wall and move the lens back and forth
till you get an image on the wall and approximate the distance to the wall.
You could try the same thing using the front cell alone and compare the
results.

Want to trade for a 360 Tele-Xenar?  Old (1957, I think) but good.

Karl Wolz

----- Original Message -----
From: "Clive Warren" <cocam@cableinet.co.uk>
To: <largeformat@f32.net>
Sent: Friday, December 07, 2001 2:11 PM
Subject: [LargeFormat] Rodenstock Sironar 180mm f5.6 - Convertible


> Just been clearing out various places in the house - well this is my
> holiday this year. Short straw possibly......
>
> Anyway, I cheered myself up by finding a couple of lenses that came
> along in a deal a while ago and had been put away safely in a
> previous tidying frenzy.
>
> One of these is a Rodenstock Sironar 180mm f5.6 in a Copal #1 -
> checked the coverage when it arrived - 234mm. Can double up for 4x5
> (it would have to be pretty special to replace the 203mm Ektar) and
> 5x7 with minimal movement.
>
> The interesting thing I have just noticed is that it appears to be a
> convertible lens. I tend to prefer mainly the Schneider offerings so
> was a little surprised to see a dual set of apertures on the aperture
> scale - for example, f16 (in white) corresponds to f32 (in yellow).
>
> The yellow scale is marked f=550 - so it is a convertible -
> 180/550mm.  The aperture for the 550mm configuration is f16. The
> front element sets are a lot larger in diameter than the rear.
> Folklore and Ken Hough always tells us to put single element sets
> (from Turner Reichs) on to the rear of the shutter. The question is,
> which element set (front or rear) on the Sironar should be used for
> the 550mm focal length?
>
> Cheers,
>         Clive
>
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