[LargeFormat] Ross APO Process 12" f9 Lens

[Clive Warren]

Just dipped into my lens box and found a Ross APO Process 13" f9 lens 
that is mounted in brass barrel and has an aperture diaphragm that 
goes to f64 and a Waterhouse stop slot. There is no coating but this 
shouldn't be too much of a problem as there are only about 6 elements 
(judged from the reflected light bulb test).

The aperture range is adjacent to a range of distance marked in 
inches rather than mm so it must be fairly old.

Does anyone have an idea of the age of the lens or some history of 
the Ross (London) lens company? I would imagine it will be a good 
performer. Currently looking at all sorts of portraiture options......

Cheers,
        Clive