Did anyone ever call 35mm film "full frame" before digital came along (except maybe in the context of those cameras that could shoot 2 or 4 pictures within a single 35mm frame)? I think you might be able to argue that anytime some refers to FF in this context they are talking digital.
No, quite the opposite. 35mm was traditionally called the miniature or leica format.
All those folk with 6D's and 5D3's thinking that 'full frame' is just the best thing ever... the medium format guys haven't even noticed you are in the room.
They certainly could have called 35mm "full frame" before digital...because aps-c (advanced photo system-classic) was originally a film format, first produced in 1996. However, it didn't really catch on very well.
"The Advanced Photo System was an attempt of a major upgrade of photographic technology for amateurs, but was soon overtaken by the popularity of digital photography. Despite the added features, APS never really caught on with professional photographers because of the significantly smaller film area (56% of 135 film). Color slide film, popular with professional photographers, proved unpopular in APS format and was soon discontinued (although chromogenic black-and-white IX240 film continued to be produced). Color print film was normally available only in a limited selection of film speeds and color formats. These developments, combined with the fact that auto-loading 35mm cameras could be made almost as compact, as convenient, and as inexpensive as APS-format cameras, prevented APS from attaining greater popularity.[original research?]
APS cameras were mostly produced in compact fully automatic form for the consumer point and shoot camera market. However, within five years of APS' 1996 launch, the rapidly-falling prices and increasing quality of compact digital cameras had reached a critical point that saw them quickly adopted by the mainstream, and APS camera sales plummeted.
In January 2004, Kodak announced it was ceasing APS camera production.
Both Fuji and Kodak, the last two manufacturers of APS film discontinued production in 2011. However, as of January 2012, limited stocks are still available for purchase."
There were lots of film formats, popular sizes ranged from the infamous disk camera with what seemed like a microscopically small area of film, up to 8x10. 35 mm was probably the most popular size among "real cameras", but smaller formats like 110 are still in use today, as well as 220 (medium format) and the sheet films for what others considered to be real cameras, like the 4x5 and 8x10 formats.
We can't really compare film formats to digital formats because of the different pixel sizes used in digital. In film, at a particular ISO, for all practical purposes you had one resolution. Bigger sheet of film captures more detail, smaller one captures less. In the digital world, you range from pixel densities of around 20megapixels to around 5 gigapixels for the equivalent area of a FF sensor. In film the limit was how big you could make the camera, in digital it becomes a hard limit where if the pixel were any smaller it would be shorter than the waveform of light and become a mechanical filter.
Who knows what the future brings? Mechanical filters are very sharp, they are the standard way of filtering signals in satcom systems, perhaps one day they will replace the bayer filter... Nobody can predict the future with any kind of certainty, but one thing is true, film is not digital, the restrictions and bounds of one are not the restrictions and bounds of the other.