Finally, a couple of Petzval's small enough to use with your Nikon! Or or or, just about anything except the medium format stuff like Hasselblad that has a back focus so long the lens has to live inside the camera. Man, are these hard to find too. They were both on theatre projectors 95 years ago, and probably had a 30 year life doing that. Then they all went into the trash I guess. Or languished in drawers in old theatres and then went to the dump with the rubble. I did a giant page at my website with photographs made WITH these 2 lenses. Get ya all fired up. You can see the possibilities for sure. http://tonopahpictures.0catch.com/GundlachKollmorgenPetzvals/GundlachKollmorgenPetzvals.html Click on the links to see images made with these lenses! The Gundlach 3 1/4" is effective f2.1!! Holy cow. The Kollmorgen is effective f2.7! These are probably best suited for electronic collectors and gorgeous bright colors. Then print them 60X80 inches and you'll have instant fame. MOMA will be knocking. That's all there is to it. I want $165 each. Your choice. First come first served. $6 bucks shipping in USA. PayPal OK.