Listen to what this poster is saying. Your normal lens on a 6x6 will be 80mm. I rarely shoot at 2.8. The problem is your depth of field gets so shallow you may only get one eye in focus. If the subject is moving then no eyes in focus. You need to pick up some medium format cameras and see how they feel. I don't own any lenses faster than 2.8 and my lenses are still beasts. I couldn't imagine what they would be like if they were 1.8s or 1.4s. I don't think those types of lenses exist in this universe because they would be prohibitively expensive and they would kind of defeat the purpose. They would be so heavy they would be a pain to shoot hand held. At least in the SLR form factor.
Originally Posted by ntenny
Trust me. Shoot with a medium format camera at 2.8 for awhile and then come back and tell us what your keeper rate is. Unless you are constantly focused at infinity I would assume it will be pretty low.