How much variation of film register is there with older LF cameras? That is, the distance from the 'mating face', where the film holder sits, to the GG focusing surface.
I was surprised to find out, only about a year ago, that the MPP technical cameras I'd been using for years had a register of 5mm. This is a quarter millimetre more than the 'standard' 5x4 register of 3/16 inch, or 4.76mm, which Toyo, Fidelity, and most other DDs and rollfilm holders adhere to. It doesn't sound a lot, but it's equivalent to a focusing error of 1 metre with a 150mm lens focused at 10 metres.
I've since had the GG seating of my MPPs milled down to the correct distance, but I'd always considered the MPP to be a 'modern' and standardised camera, being of 1960s vintage.
It appears that even after the introduction of the international or Graflok back, some camera and filmholder makers were still going their own sweet way when it came to this important dimension. Graphmatic backs, for instance, appear to all have a register of 5.5mm! At least, the ones made under license in the UK by Wray have.

So, all you owners of older LF cameras. What's your register? And is it compatible with modern DDs, or was your camera only meant to be used with the makers own filmholders?

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 21, 2001

Answers

I don't know the register of my camera, an MPP Mk7 by the way, and I have noticed results are sharp using various holders ranging from the Linhof dual plate/film darkslides to fidelity delux and elite holders. Also when I still had it, the results from my Wray Graphmatic were possibly sharpest.

-- David Kirk (david_j_kirk@hotmail.com), February 21, 2001.