Around when I started (again) photographing more seriously, I'd crop the photos however I please. If it looked good in panoramic, I'd cut the top and bottom, If it looked good in square, I'd crop it to square. Not much thinking went into framing at the time.
Then I happened to read a comment on a photo forum on some photo contest where a heavily cropped image (a pseudopanoramic if you will) won - going like "how could a cropped image be better than uncropped ones". To put it another way "The Real Photographers scan their pictures with negative borders included". I did that for a while (these are my experiments on film), because, lets be honest, it felt right thing to do at the time. And it taught me a whole lot about framing and intent. But for me it stops there - the negative borders have a didactic value if you really respect them and don't add them to your digital images. Any serious presentation with negative borders has a wannabee feel for me. They're tolerable in a book, but certainly not on exhibition prints. I know the previous sentences hit photographers like Dan Winters, but is he really in a desperate need to show his images are uncropped and shot on film? Doesn't his work stand without making such statements? (It's a rhetoric question - it sure does, so why the borders then?)
I stopped shooting film long time ago, but I kept following 2:3 format strictly, because it was natural thing to do as the cameras I used shoot this format. Also it was easy to present my pictures side by side when they were in the same aspect ratio. I didn't shoot series yet, but having uniform look went up on the importance scale while having uncropped image went down - you can crop and still maintain the same aspect ratio. But these were very slight crops just to maybe fix a one degree tilted horizon or cut out some obstruction even not covered by viewfinder. My first two exhibitions (Dark Matter and Unfinished Stories) were all 2:3 images in landscape format, not a single portrait (format).
Once I started Blood Unquiet, it became increasingly clear there'll be images in portrait orientation, even the very first drafts had vertical images. 2:3 vertically is ugly as hell, in my humble opinion. It's just fine horizontally, but the vertical version doesn't fit into my definition of 'beautiful'. I didn't want to use 3:4, because it very much associates with the time I shot compact cameras, so I chose 4:5. I tested also 6x7 , but this was too square. And square is just too androgynous for me (I've nothing against looking at good square images, but I can't compose in square).
Next problem - none of my cameras shoot 4:5 natively making the visualization much harder. I had to get used to visualizing 4:5 image inside the 2:3 viewfinder. But it's well worth the hassle as it makes presentation so much easier - if you're interested in what I went through finishing and formatting Blood Unquiet, you can read my Exhibition Considerations series from this spring (scroll all the way down, it's in reverse order as usual for blogs). This was the time when I started to use live view much more than I used to before as the camera can be configured to show 3:4 crop marks on the screen. That's better than nothing.
When I finally happened to shoot Polaroid (which is very close to 4:5) it felt really natural. I'm really looking forward to the time when camera companies start making sensors with different aspect ratios or at least implement cropping in a usable way. I certainly wouldn't have anything against native 4:5 digital camera and why not a real panoramic one? Meanwhile I feel the pull towards 4x5 film cameras - I'd really want to make myself familiar with one, but I don't rush to buying yet. I'd give it another thought if New55 was usable without fixing it (fixing as in pouring a liquid fixer onto a tray and washing the negative in it). I can live with scanning, but I'm not into handling chemicals, that's not even a convenience thing, but rather something I'd call childhood trauma.