I never used them, so maybe I’m wrong, but aren’t they just things you put in front of an existing regular phone camera (for example 24mm on the new Iphone) and then they just take a picture with a 24mm opening, but looking through whatever 120mm telephoto objective you stacked on top, without it having an effect on the photo quality?
In other words, if a 24mm opening can let a certain amount of light and information to the sensor, do the telephoto lenses change that somehow or is it literaly as if you pointed the phone through a binocular, since whatever passes through the telephoto then has to filter further through the standard 24mm lens?
Yea, sort of. The “telephoto” lens will definitely be degrading the image quality because for one, you’re putting a lens on top of the existing lens, too many optical elements. Two, light transmission would probably reduced, given that the aperture would be smaller than f/1.
And btw, nobody can put a binoculars in front of a DSLR to have a usable image, the lenses tend to be wider in diameter than the binoculars.