Sirius Glass
Subscriber
Although IMO opinion John Hicks, a good photographer and a great person I bet, talks about a couple of relevant, valid things in his "comments", some of his words there don't seem to reflect experience in real low light photography... I repeat: in my opinion.
Examples: medium format is never the best option for low light + moving subjects. If you do landscape of any kind and you use tripod, no problem of course, but, f/2.8 for low light? I hope he's not talking about handheld photography. When light is low, even at f/1.4 @3200, speeds are low, like 1/30th and 1/15th. In those cases f/2.8 is totally useless if we need people without blur.
35mm and any f/1.4 lens are much better tools. Plus, we get a lot less DOF, at the same f-stop, if we use medium format instead of 35mm.
And what he says about rectangles made me smile: we don't use 6x6 to crop for a rectangle, but to compose for a square. We compose for a rectangle with 35mm or with 6x9.
6x7 doesn't replace 6x6, and it doesn't replace 6x9 either.
For low light level photography a tripod is needed for longer exposures. With the longer exposures people and other moving object will start to blur at some point. If blurring is acceptable then proceed. Otherwise use a larger aperture or faster film. Simple and direct.
I am looking for film speeds of 3200 because I want to use them with long lenses and therefore the maximum aperture is limited if I want to use shutter speeds of 1/250 second or 1/500 second to photograph wildlife. A tripod is needed because of the mass of the lens and the need to hold the subject in the field of view for long periods of time. There can be no fill in flash at those distances and the subject are not interested in moving to better lighting for my convenience.