Re: 4x5 requirements?

[John Sparks <sparks@xxxxxxxxxx>]

Roger Hein wrote:
> 
> Thanks for the info George.  As it happens I also use a Wisner.  Any idea
> how or if your friend got around the bellows problem?

I also have a Wisner and wanted to use 4x5 IR film.  I talked to Ron
Wisner and he said they sell an Infrared safe bellows for $80.  Pretty
cheap as bellows go (and only the cost of 2 boxes of 4x5 HSI film!).

I had an extra back for a speed graphic and made a 4x5 reducing back
for my 8x10 Canham which does have an IR safe bellows instead.

> Also, how much focus correction do you apply when using your Graphic?  I
> assume that like most view cameras there's no IR focus mark (or even focus
> scales for that matter).

I haven't worried about the focus correction and just stopped down to
f/32.  Everything has been quite sharp.  The correction I've seen is is
so small that it's pretty hard to manage (increase extension about 1/2mm
for a 210mm lens at infinity).  You may want to bias your focus point
toward slightly closer points in the subject than usual.  Unless you are
using an visibly opaque filter, there is still plenty of visible light
affecting the film so you still need to have everything in focus by visible
light anyway.  You just need a little bit more on the close end to cover the
IR.

John Sparks

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