That's a whole lot of weird tapdancing by those companies. To me, it's not a hard philosophical question at all: a photo is an accurate representation of the light that was received by the camera.
Anything that makes the image vary from reality means it's no longer a photo, but an artwork based on a photo.
> Anything that makes the image vary from reality [...]
I'd argue these are not equivalent definitions. Demosaicing, red eye removal, exposure/brightness/contrast adjustments, white balancing, distortion correction, stabilization, etc. diverge from the exact light received by the sensors, but generally produce better representations of reality.
Digital photos necessarily have at least some processing, and I think there's a gray area where it's hard to draw an exact line (e.g: how smart can you go with interpolation and noise reduction).
I was perhaps a bit too brief, but I stand by my distinction. With the exception of red-eye removal, the rest of the modifications you mention are intended to remove the distortions introduced by the photographic process itself, and so bring the photo closer to the real image, not further from it.
But if you're using things that take the photo further away from the actual image (like beauty filters and other things that add information that wasn't there or distort information that was), then what you end up with isn't a photo at all in my mind. It's artwork based on a photo.
Sure, could say that the lens itself is altering the light and thus no longer an accurate representation of the light received by the camera. Particuarly evident with something like a fish-eye lens.
My comment is questioning JohnFen's definition that a photo must be an accurate representation of the light that was received, to be clear. Any existing photo will diverge from that in various ways, often because it better captures reality (or that you can't really capture much at all without it).
yeah, I was using "light received by the camera" as shorthand for "objective truth". No photograph perfectly reflects the reality it is trying to capture, of course, because the process itself introduces distortions. But that's an expected margin of error.
My distinction is about how far the photo is from what I'd see if I were looking with my own eyes. If a photo is enhanced in a way that makes the image different, then it's photo-based art and not really a "photograph" anymore. That resulting photo-based art may express some sort of truth that just the image doesn't, but that doesn't mean it's not a piece of art rather than a plain recording of reality.
As a more extreme example of the sort of thing I mean, look at the Samsung "super zoom" functionality a couple of years ago where the camera was straight-up replacing the moon in photos with a fake moon image that looked better. That clearly makes the "photo" no longer an accurate representation of reality.
Lets expand that definition a bit then. Lets say that I use a flash in a photo, does the result become a "photo" or "artwork based on photo" in your definition? I'm altering the light received by the camera.
What about a neutral-density filter? polarizing filter?
So if I use a lens with a higher rate of chromatic aberration then say a super expensive lens with less chromatic aberration, does the photo I take become "artwork based on the photo" as its altering the light received by the camera more.
I think the use of a flash is irrelevant. It doesn't make the camera alter the image it received. I think I covered the other points in my other clarification comment.
Anything that makes the image vary from reality means it's no longer a photo, but an artwork based on a photo.