Bellows frame size ?

[Laurent]

Hi,

after the question about lens boards, I have a similar one for bellows : being building the view camera from Jon Grepstad's design, I'd like to use a used bellows to avoid making my own.

I know from the building documentation that a Cambo bellows has panels of 162X162 mm. My issue is I found one used Cambo bellows but it's 108€, and that makes a big difference in my budget. As I saw some Sinar and Toyo bellows for half that price, I wonder if I can adapt them.

So I'd be happy to know what are the frame sizes of Toyo and Sinar bellows.

Thanks for your input
Laurent

 

[rbarker]

The standard Toyo 4x5 bellows frame measures 158mm square (outside) and 125mm square (inside). The corners are rounded with a radius of about 8mm, and there is a light-trap at the edge - a lip about 1mm thick, followed by a trough of about 4mm wide by 4mm deep. Around the outside, there is a 5mm lip between the edge of the frame and the outside surface of the bellows. That lip is used by the securing slides on the standards, top and bottom.

Note that the design of the Toyo bellows frame matches the dimensions of their 158mm lensboards and the attachment side of their backs. Thus, it would be possible to use that design as the basis for various other special features.

 

[Laurent]

Thanks a lot for these precisions !

 

[Laurent]

I finally made my choice for a Cambo in mint condition, since the cheaper Toyo was in bad shape.

So here are the Cambo measurements if somebody is interested :

The frame is externally 162 mm, corners are round with a radius of about 10 mm
The internal opening is 117 mm, there's a lip of 1.5 around it (1mm height) so that the frame's lip will fit in a 120 mm opening.
Around the lip is a rabbet of 4 mm by 2mm depth.

I also bought a very cheap Sinar in bad shape (but still usable) that will make a hood.
The dimensions are :

Frame external dimension is 139.5 mm, internal opening is 120 mm.
There is no lip, but a light trap of 135 mm external, 128 internal, and 2mm depth. Radius of the external part of the trap is about 2mm.
The bellows could be held by an external rabbet, which is 3mm thick and 2.5 depth.

In this aspect, the Cambo is the easiest since it has a wide frame around the bellows, which makes attachment easy.