Rodenstock 480mm on 4x5

[Shutter]

Hey,

I'm thinking about buying a Rodenstock 480mm f9 and using it on my 4x5 Sinar F2 - but I don't know anything about the lens and I haven't found anything on the web...
So here are my questions:

1 How does the lens perform on smaller formats? After all the lens was designed for 8x10 and I'm concerned that the large coverage might cause a lack of detail/sharpness...

2 What bellows extension is needed for a working distance of approximately 3m?


TIA,

Chris

edit:

no need to reply, I won't be able to use the lens because the behind-the-lens-shutter I was going to purchase with the lens is broken

[Emmanuel BIGLER]

Hello and Willkommen to the apo-ronar fan-club.

The lens will be diffraction-limited when you stop-down to about f/32-f45. The 240 mm apo ronar is diffraction-limited at f/22. So probably you have to stop one of two clicks more for the 480 in order to get the best possible image quality with this lens.
So : no problem at all.

Bellows extension : the relevant formulae are
required additional extension = (magnification) x (focal length)
(1+ 1/magnification) = (distance from lens to subject) / (focal length)

here = distance = 3 metres = 6.25 focal lengths
magnification = 1/5.25
additional extension = 480/5.25 = about 90 mm no problem
Total bellows length : about 480 + 90 i.e. about 570mm.
Explanation ; the apo ronar is a symmetrical lens ; hence the distance between the lens board and the focal plane is close to the focal length. For far-distant subjects this position is about 480mm behind the lens board. The additional extension is to be added with respect to this (infinity->focus) position.