Oh, so that's what it means...

The APS film format came and went while I wasn't paying attention. It showed up a couple years after I'd stopped working in the photo biz, and by the time I was paying attention to cameras again, it was 2001 and I was buying a Sony Mavica digital camera and film photography itself was collapsing precipitously.

The Nikon looks like a regular SLR, while the EOS IX is self-consciously '90s cyberpunk

The name survives because what we currently refer to as "crop sensor" DSLR & mirrorless cameras use a sensor that gives a "crop factor" of 1.5X (1.6X on Canon) and is referred to as "APS-C".

As it turns out, there are three ways you can shoot a picture on an APS film camera. The standard one, which uses the entire negative, is in a 16:9 aspect ratio and called "H" on the camera, for "High Definition", since HD video was a new and novel thing at the time. There was also a mask that would crop the sides off the image to give a more traditional 4:3, referred to on the camera as "C" for "Classic". Finally there was a "P" mode for "Panorama", which aggressively cropped the top and bottom of the image for a 3:1 ratio, which returned 4x11" prints.

Note that the image was only cropped in the viewfinder, using LCD or mechanical masks, or sightlines, and the instructions for each print size were encoded on the film for the lab's printer to read. The actual negatives were all recorded full size for each image.

The name "APS-C" survives as the most common sensor size in DSLRs because sensors were crazy expensive to make. Camera companies had experience projecting images onto a piece of film this size, so there we were. As sensors became relatively cheaper, and relatively easier to make efficiently, ones that are the same size as legacy 35mm film became more common. (This is because lenses are the important thing in photography. Get bought into a lens ecosystem, and you're likely there for a while.)

Incidentally, APS-H lived on into the digital era as well. While Nikon's first pro digital body, 1999's watershed D1, used an APS-C sized sensor and didn't increase the size until going full-frame with the D3 in 2007, Canon thought that pro photogs needed more sensor real-estate. The sensors in Canon's 1D, their first in-house pro body in 2001, were larger, giving a crop factor of 1.3X. Because of this crop factor similarity, they were called "APS-H", even though they used a standard 4:3 ratio.

To give an idea of how much the price of the sensor affected the price of the camera, the APS-H 4MP EOS 1D dropped in 2001 for $6500, and a year later the full frame 11MP EOS 1Ds joined it in Canon's lineup for a whopping eight grand. That's better than $200/MP or, looked at another way, seven dollars per square millimeter of additional sensor size. At seven bucks a square millimeter, the head of a pin would be $28 and a penny would be almost two grand.

(I had thought that the Canon EOS IX and Nikon Pronea 6i were the only semi-serious APS film SLRs out there, but it turns out there's another!)
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