Re: ATM [~OT] Roll film holder plans?

[Aplanatic@aol.com]

Matt wrote:

>  > Does anyone know of 'net plans for a roll-film holder/camera body? 

Dominic responded:

>  The best I have seen is actually the back from a Hasselblad.
>  It is smaller than any other I have seen. Pro camera shops
>  in San Francisco area have been selling these for about
>  200 USD, but I think you can do better at a camera swap.

I use a Hassy back on my concentric Schmidt Cass as can be seen here:

http://members.aol.com/aplanatic/slevogt/ota_oag.html

There are two problems with this back.  First, there is some non-flatness of 
the film which can be as large as 3 or 4 mils, and I have also found that the 
distance from the interface to the film is quite a bit different in different 
camera bodies.  Up to about 5 or 6 mils in the three bodies that I have.  
This second problem can be overcome by careful measurement and calibration.  
The first problem cannot easily be solved.  In my f/4.5 camera the film 
non-flatness definitely makes a difference and can cause soft focus from time 
to time.  The Hassy back is nice and very convenient, but if I had to do it 
over again, I would probably build or buy a vacuum back for medium format 
work.

Dave Rowe