I'm not an expert, but would call myself a "newbie collector." I own four Petzvals at the moment, dating from from 1850s to early 1870s, including Grubb, Voigtlander, Derogy, Darlot. I've been zeroing in on lenses made before 1860 and am especially after a lens from the 1840s. I also own a pillbox lens made in 1855. I have some thoughts. Your lens is a good length, a good brand, and the glass is in good shape. On the negative, it has no flange and the brass is a little rough looking. Another thing is that lenses made before 1860 or so did not have slots. Yours does, making me wonder if the slot was added later or maybe the lens was actually made after ~1860 (less likely since many added the slot.) I'll take a rough stab at a price, something the wiser Steven Tribe passed on here. I'm going to say the lens would probably sell in the $400 to $650 range on eBay. If I had to guess a specific price, I'd say $500. Again, that's a guess and it depends on how badly two people want a Ross lens. Note that last month I bought an even rarer lens, a Grubb Petzval made in the 1850s for $360 (no flange). The CC Harrisons and Voigtlanders seem to go for much more, all things equal. As Steven said above, most people who really want an 1850s Petzval already have one. That's the case for me, too. I have two, I think, and may sell one this year. Now if you can come up with a lens from the 1840s, I'm interested.


Kent in SD