Excellent points about depth of field with 6x7 format. Consider the 35mm camera using 85mm f/1.8 for subject isolation in portraits, the 6x7 portrait lens is often a 150mm f/4. Note that Bronica GS-1 was built to be a lighter 6x7 than Pentax and Mamiya. All lenses are leaf with maximum speed of 1/500 and the lenses are slower f stop which keeps the
lenses lighter and smaller. Fastest lenses are 80mm f/3.5 and 100mm f/3.5. The 150mm is equivalent to 75mm and the 200mm is equivalent to 100mm neither is particularly close focusing thus an 18mm extension tube is used for close headshots.