Hang on. If I’m shooting a subject ten feet away with a 35mm lens, then switch to a 70mm lens to “zoom”, did I not just change the optics to make the subject bigger?
There is no 70mm lens, it's 48mm and 77mm on the Pro and 48mm and 120mm on the Pro Max. But yes, if you switch to 77mm/120mm it uses an entirely different lens, it's the one on the middle right when looking at the back.
Since this seems to be about semantics technically you didn't zoom at all, you actually switched out the entire camera. Both different sensor and different lens. So if this is about Apple calling it optical zoom and whether it is that, Apple uses the term because that's how it effectively works for the user, no matter how it's achieved from a technical point of view. Optical zoom is what we understand to be the counterpart to digital zoom.
It’s not cropping or zooming in digitally, it’s an optical change to obtain a closer view.
When going from 24mm to 48mm it uses cropping but the resolution remains at 12MP. There can be a small reduction in quality since only the main 48MP sensor and only at 24mm can make use of the entire sensor area. By default these still come out as 12MP, but the quality should theoretically be better since it was able to use the full 48MP sensor for the 12MP shot. That goes out the window once cropping is used. Though the 14 Pro also used the same method and AFAIK there was barely any difference noticed if any.
I would agree that anything between 1x and 3x is not optical, but they aren’t claiming it is. The 3x “zoom” is optical because it’s a change in the lens, not a digital change after processing.
Apple does claim the entire range is optical zoom if you look at the specs and they aren't wrong. None of these are digitally interpolated (digital zoom) but not all change through which lens the photo is shot. Since the resolution always remains at 12MP and no digital interpolation is required they can call it optical zoom and that's how it behaves. If Apple said in the ads that it isn't digital zoom but not optical zoom either, they'd get a lot of confused customers.
I'm just guessing here, but I think it still uses the main 48 camera when using the 5x telephoto camera, for best post processing.
The 5x 120mm on the Pro Max and the 70mm on the Pro use a separate lens with a separate sensor, it's the lens on the middle right if you look at the back of the phone. The main 48MP sensor is used for 24mm, 48mm, and the steps in between.
If it's a digital zoom, then they should not advertise it as optical zoom.
It's not a digital zoom. Shooting at 24mm results in a 12MP photo by default and shooting at 48mm results in a 12MP photo as well. There is no interpolation going on, no digital zoom was applied. And if you claim crop is equal to digital zoom then by that logic all DSLR cameras that don't use a full frame sensor use digital zoom for every photo. That is obviously not the case, the sensor area is just smaller, hence the crop.
For all intents and purposes it is optical zoom since all photos always come out at 12MP, whether at 24mm, 48mm or 120mm on the Pro Max.