Brian, Either of the G-Claron's is useable as a convertible by removing the front group. The 210 becomes a 370, and the 355 a 615 or so. Much of the correction is diminished with only one group which can be a bonus for portraits. Of course the aperture scale changes by about 1 2/3 stops or actually more like 2 full stops for the increased bellows at portrait distances. Give it a try. Won't cost you more than a few sheets of film. Polaroid even better.