I use a 5x4 LF camera with a 6x9 and 6x12 rollfilm backs, both of which I consider to be medium format. I would consider LF to cover any film sized 10cm x 10cm and above. This is a more satisfactory definition than defining LF as being sheet film. I have an adaptor which enables one to take two seperate photographs on a single sheet of 5x4 - photographs I would define as MF.
Is using a roll film back on a 4x5 body considered large format photography?
Is using a 35mm film back on a Mamiya 645 considered medium format photography?
Which matters more, the tool or the image? From my perspective, MF = 120/220, LF = sheet film.
It's all just labels, really. The only time I can conceive where it's relevant would be if you were wanting to join a large-format users' group on the basis of owning and using a 6x9 folder. Depends entirely on their interpretation, not yours.
Right now in Spain they're holding the Running of the Bulls,
followed by the Soiling of the Pants,
and the Burying of the Idiots.
In my darkroom, I've have to use the Beseller 4x5 enlarger to print by enlargement those 6x12cm negatives, as they can't be accomidated in the 23C enlarger. So, in this respect they're LF negatives; but I have to agree with most of the others that LF generally implies sheet film, not roll film. (Ignoring such exceptions as 9.5" aerial surveillance roll-film cameras, and using a MF back on a 4x5, etc.)
but, I really don't know why it matters. If you make photos with this camera or that...or another, and the result lightens your spirits...who cares if it is large format or meduim format or pano? Why does it matter?
Brad, I agree.. but for some people calling anything on roll film LF is as offensive as calling a porpoise a fish.
<chuckle> reminds me of a trip I made to the jungle with a group of biologists. I found a cicada on deck one night, and having never seen a grasshopper(?) that big I caught it and preented it to one of the bio guys saying...."What kind of bug is this?"