Hello LF fans! I'm talking to someone about an old B&L Protar convertible lens, 8 3/4" - 11" - 13 3/4", in an old air regulated shutter. I have yet to see it in person. I've talked with Steve Grimes about it, primarily about the shutter, but he said it might be a "Casket Set" due to the five aperture scales on the shutter. I've read the disadvantages of "convertible" lenses but at the same time I've read they will sharpen up some with the use of a yellow or orange filter when using B+W film. Does anyone know anything about this lens? It's quality, usability, coverage or anything else? Is there another convertible that might be better? Your help would be greatly appreciate