I have only attended a few semesters of photography and a semester of art in college, so most of what I have learned has come from scouring the interwebs and forums, watching Dean Collins videos, reading textbooks and looking at pretty pictures in magazines. But I have been able to cobble together a rudimentary understanding of photography and start to get a handle on what I like and why.
For my personal goals I see a great many pro’s and cons of the varying dimensions of capture size on 120 roll film.
One advantage of 6x6 is the option of cropping to vertical or horizontal after capture. However for me this is outweighed by the fact one is throwing away a large amount of data that one can keep by originally recording in the desired field of view, as well as the subsequent waste of film and chemistry and money.
Also, having been initiated into photography through 35mm I have grown to prefer rectangular formats.
The 6x4.5 format is apparently great for weddings. I don’t like to shoot weddings; they freak me out. I never found much use for this format.
The 6x7 format enlarges without crop to 8x10, 11x14 and 16x20. This seems very useful when selecting ready-made frames.
The 6x8 format more closely fits 8.5x11 & 10x13 magazine and annual report full-page images with little cropping. I have never used this format and the little magazine work and AR work I did was primarily with 4x5, 6x6, 35mm and APSC digital. Bummer.
The 6x9 format mimics 35mm and felt very comfortable to me on the handful of occasions I’ve had to use it.
The 6x10 format, I think, might work well for landscape work here in the American west but I have not tried it yet, hopefully in another month or so.
The 6x12 format is, I’ve heard, well suited for a combination of shooting ease, resolution and fairly substantial panoramic printing size; far more beneficial than extracting similar ratios from lesser dimensions.
For me a greater point beyond pure resolution has become the overall “feel” of an image and an important aspect of this is depth of focus falloff; I have always really liked the subject separation one gets with a larger sensor or film size at any given aperture.
I remember what a revelation it was when I read that depth of focus is consistent across focal lengths when keeping the subject proportions consistent. That never occurred to me because I had only seen the results of NOT keeping the subject proportions consistent.
This
is explained really well on the web so I will not try to regurgitate the facts. The bottom line is one needs a much greater aperture to achieve similar depth of focus falloff on a smaller format and these ratios can be found on the internets as well.
But since all things are NEVER equal in my world I have learned that I like a greater dimensional format on roll film than a smaller and here is why:
I can get closer with a larger format and get greater depth of focus falloff with a smaller aperture lens of lower cost than with a smaller format and the same lens.
With a larger format I have greater room for lens plane and film plane movement at any given subject distance.
As I continue to learn I may find additional reasons to prefer a larger format. However, I can imagine these factors may inversely and negatively impact someone shooting macro photos, but I have no real world experience with that and can only imagine.
I just remembered when I was shooting jewelry, that's like macro, sort of. I used Rodenstock Makro lenses all the time with movements on 4x5. But only the rings and watches were sort of like macro, and not really tiny macro and I am tired of typing.
edit: A roll film back would have probably have been a very good choice for some of that now that I think about it.
If someone sees I have made an error please correct me as soon as possible.