Sorry lads, you'll need a 9X9 or perhaps the teeny Deardorff 8X8 lens panel to mount this giant on. This was made by Bausch & Lomb around 1900 - 1905 - ish and inscribed with the sellers names, not B&L. This one as you can see is Wallach Sweet & Co. of Chicago which was a large photo retailer. These large photo houses bought these and sold them as House brands. Bausch & Lomb and Wollensak did a lot of this kind of marketing around the turn of the century. This lens casts a magnificent image on 8X10. They conservatively listed it as 8 1/2 X 6 1/2 because it is a copy of the Dallmeyer Patent Petzval 3A. A couple of items to note; The aperture is silky smooth but 3 of it's blades are now gone. It makes a perfect circle until about f11, then you can see it's not quite perfect. f11 is about all you would ever desire, in fact, what you buy an f4 petzval for is to shoot it wide open. That's where they're the most gorgeous. Also, this once had the rotating rear glass for diffusion. Some time in it's life the threads on that were damaged and it's nearly impossible to turn. Not a feature anyone cares much about, it didn't work all that well. It was more an advertising ploy. $895 plus shipping for this.