Brass lens suggestion for a 4x5 camera

[Ray Heath]

Hi Jimi
My camera is not a sliding box I use the rack and pinion to focus.
It doesn't focus as close as I'd like for still lifes etc.
I'm thinking of building some kind of step out mount for close up work.
Not really a problem though as I have a second mounting ring that I can use to mount this lens on one of my larger sliding box cameras that has a 4x5 reducing back.

[Steven Tribe]

I'll check my Ross CdeV sources sometime to-day. I still think it is a no.2!

One of the problems with early catalogues is that there was a tradition of giving the "back" focal lengths, not the effective focal lengths. This is quite logical really as many cameras did not have fine adjustment and used the adjustment on the sleeved barrel to do this. A camera owner could see if his camera was OK for his lens at infinity. And, before the advent of Waterhouse slots (around 1857) there was no marker from where to measure the efl from on the barrel.

I seem to remember that the Ross CdeVs were not completely constant through the 1850's and 60's. I have all three sizes, two are with the type engraved, and the third is like yours and is obviously the intermediate size no.2.

Another characteristic of the early Ross CdeV is the ultra thin lens hoods, which are often either damaged or completely lost from the soldered connection.

My later no. 3 has a diameter (front lens) of 70mm and a efl of over 7.5".

[Carsten Wolff]

e.g. Lancaster and Son's small landscape brasses are ~135mm afaik, not expensive and cover 4x5 with ease. Being simple achromatic doublets, you can play with open aperture sharp centre only to small aperture and pretty much everything sharpened, provided you can suss a shutter... but I'm sure there are tons of other lenses out there that fit the bill.

[Jim Andrada]

Something in a Volute shutter looks quite the cat's meow.

[Steven Tribe]

G'day Steven
Thanks for the info. I found a page at http://antiquecameras.net/rosslenses.html that shows what appears to be original Ross advertisements.
If I assume that the stated measurements are a bit loose then my lens would match the stated specs for a CdeV No.3, 2.5 inch diameter and a focal length of 6 inches. Which I actually measured to the waterhouse slot to be closer to 6.5 inches.

I found time to-day to check my thought that the Ross catalogues at:-

http://www.antiquecameras.net/rosslenses.html

are, in fact, back focal lengths - rather than effective focal lengths.

I checked the measurement of all CdeV sizes and can confirm that they all give efls which around two inches longer than in the catalogues. These misleading focal lengths extend to the Portrait series as well, where the focal length of size 3 is given as just 10" - it is really around 12"!