This is a gorgeous old Ross Universal f5 Petzval of approx 10" focus. It has slot for Waterhouse stops but I don't have any for it. Ideally this would be the perfect lens for 6.5X8.5 format if you want weak / swirly corners. On 5X7 which is probably what it was designed for, it's going to have pretty decent manners, and on 4X5 it's going to make gorgeous portraits that would have made any technician happy in 1931. 8X10........now that's a stretch. How do you feel about dark corners before the swirlies begin? I have 2 other larger Ross Universal's and I love them, but it's time for me to begin downsizing a bit. Size is what is the neatest thing about this lens. It'll fit on a 4X4 lens board, and might even be a good candidate to have a machinist put into a Copal 3 or Betax 4 shutter for you if that's your thing. I would like $365 + shipping for this.