Words have more meaning to me. I try to understand the concept before I describe it, like an engineer who is careful to use the number "2" when he means "2" and NOT "3" -- however similar they may be in value.
Large Format describes a relationship rather than a specific size.
Relationships only make sense when we understand the context. If you have a client that likes looking at 'chromes on a lightbox and always describes 6x6 transparencies as "LARGE FORMAT" as opposed to 35, only a pedantic twit would insist the guy paying the mortgage was wrong.
For me, shooting 4x5 seems to have more in common with shooting 6x7 and 35 than it does 8x10. It is fastidious. The image must be enlarged. Diffraction is always an issue. A loupe is necessary. And so on.
With 8x10, I don't need a loupe to focus, I can set up a shot without a level and am generally relaxed when I'm working. I don't need to think about how the image will enlarge, and naturally enough don't think about grabbing the 8x10 kit ( bag of camera, bag of film, tripods, and ditty bag ) and running to catch a shot a quarter mile away.
I use a 35 rangefinder, a 35 SLR, a 120 TLR, a 120 RFDR, a 4x5 Press Camera, and a Monorail.
There is an intuitive relationship between each piece. There is a continuum: a progression from 35mm to 4x5 that has no breaking place. Outside that continuum is the world of Large Format.
For me, "Large Format" is 8x10 and bigger. Smaller than 8x10 is simply "Not Large Format".
The important thing is to establish for yourself what is Large Format and what is not. I know a few guys for whom an 8x10 Deardorff is their only camera, and the phrase 'Large Format' is without meaning.
Think about something you have only one of, and try to differentiate it from itself: "This is my favorite Left Ear, although THIS is my EXTREME RIGHT EAR."
And, ahem, the notion of "Ultra Large Format" is both redundant and silly. Unless one is describing a camera that is too big to be of practical use, there is no point in Ultra Describing It. "Large" signifies something ample and abundant; it can suggest something lavish or EXTRAVAGANT. A categorization for abundantly special cameras that are not merely AMPLE but "especially extravagant" is PRETENTIOUS.
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