One of the lenses I picked up over the past Winter was a 12" (300mm) Bausch and Lomb brass projection lens. It came off a B&L Balopticon Model C Magic Lantern slide projector from around 1915. It doesn't come apart so I couldn't check the lens configuration more closely but most of these lenses were of a Triplet design with no aperture iris. My starting guess for the true aperture of this lens is around F6.7 which is what one of my other projection lenses, a 15" (380mm) off a Balopticon has as its aperture.
This scene is from one of the White Birch Tree forests at the Marion Brooks Natural Area in Elk County, Pennsylvania.
1947 Pacemaker Speed Graphic 4x5 large format film camera.
12" Bausch & Lomb brass projection triplet lens used with focal plane shutter of Speed Graphic.
Ilford FP4+ B&W film, shot at ISO 125.
1/500th second at F6.7(ish).
Developed in Adox Rodinal 1:50 dilution for 12 minutes @ 20 degrees Celsius in Jobo Multitank 5 with 2509N sheet film reels with drum placed on Unicolor Uniroller 352 auto-reversing rotary base.
4x5" negative scanned with Epson V600.