>>3944007>Can someone eli5 for me why an iphone with a focal length of 26mm cannot take a in focus photo at less than arount 16cm or so?
Simplistically, the closer you need to focus, the further away you need to move the lens assembly from the sensor. This limits how close you can focus, either by the length of the barrel in a normal lens (fitting a longer barrel would make the lens too bulky), or by the thickness of the phone in smartphones. This quickly becomes impractical, since focusing closer and closer you need to move the lens disproportionately further away from the sensor. Gaining a couple centimetres of closer focus you pay a hefty price in bulk.
You can achieve the same result (close focus) optically by rearranging the lens elements instead of moving the whole lens assembly further away, but again at some point you reach similar limits.
This is by far the main reason phones don't focus extremely close, since they try to be as thin as possible.
For camera lenses bulk is still the main issue, but secondarily other concerns are:
1. since lenses are not perfect and don't perform the same across different focal distances, you need to prioritise at which distances the lens is optimised, and for "typical" (non-macro) lenses, performance suffers at very close focal distances
2. a long barrel, very close focusing lens makes the focus throw very long which is impractical (both for manual and AF lenses) when trying to use it at normal focusing distances>Additionally I dont understand why the telephoto lens wouldn't be the lens you would use when taking macro shots.
Telephotos require even greater distance to the sensor to achieve similarly close focus as wides, and given that they are already "thicker" (sitting at a longer distance) to achieve normal focusing distances, making them macro would make them far too thick for a phone.
That's the reason why, say on the new iPhones, the macro mode uses the superwide (and not even just the wideangle lens).