And to answer your other question about larger formats, a 210 mm lens on 4x5 is equivalent to a 65 mm lens on 35mm format. you could argue that 4x5 photographers should be using 300mm lenses, but they often don't. reasons being inadequate bellows extensions at close up portrait distances and very limited depth of field. same depth of field as with a 300mm lens used with 35mm format, only you have to be closer still with the larger format. with an 8x10 you'd have to use a 600mm lens to be equivalent to an 85mm for 35mm. One of reasons you see so little 8x10 portrature is that's it's so hard to do.