I recommend CF and later lenses because
- parts [springs and B50 filters] are getting harder to find and service can be a problem
- the ergonomics are not as good, changing the aperture and shutter speed at a given EV is awkward for C lenses
- One set of B60 filters will work for most of the CF and later lenses, some of the larger diameter lenses of the shorter and longer focal lengths use larger filters
I have only two C lenses: the Fisheye 30mm and the 500mm lenses only because the price that they were offered was so low that I could not pass them up. I have the 30mm Fisheye, 38mm Biogon SWC, 50mm, 80mm, 100mm, 150mm, 250mm and 500mm lenses.