In the film era, I used 6x12cm backs on my Arca-Swiss F-Line 4x5" technical camera. This worked great for making slides for double-spread magazine prints with a Schneider 90mm or Nikkor 65/75mm lens. If I put my bigger 8x10" view camera into "action" (if such a word can be applied to this monsterous bulky camera device), there was 6x17cm back to be inserted as well. Almost all of these large-format slides are deposited to my stock library and I only have a few mediocre scans available.
The bigger cameras become very expensive to operate over time, so towards the last years of my film-based career, I used the comparatively nifty and neat Hasselblad Xpan instead. Of course it wasn't a genuine Hasselblad, only by the label, as the camera itself was a Japanese Fuji design. The Fuji (or Hasselblad) lenses for the XPan were good-excellent performers, although prone to vignetting due to the wide coverage. Thus one should really use the dedicated anti-vignetting filters unless "speed" was of greatest importance.
I'd confess I liked the Xpan better than the Arca-Swiss, as it was faster in use and much more economical too. Plus being smaller and neater, I could even shoot hand-held.
One of my favourite XPan captures is below. Here I had to remove the centre-spot filter as it was getting dark despite the snow and the XPan had only up to 8 secs. exposures. You might set the camera to "B" and lock the shutter release, but the camera would override you and close the shutter after 8 seconds, no matter how long exposure time yu would need. A true design flaw which I complained about to the Hasselblad factory. They just shrugged their shoulders and "saw no reason to change the design, because it was perfect". For whom?
