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Having studied technical optics (in the analog camera age) it's just so hard for me to imagine that those tiny, tiny apertures we have on our phones can replace

Having studied technical optics (in the analog camera age) it's just so hard for me to imagine that those tiny, tiny apertures we have on our phones can replace a well designed lens. However, I'm not a skilled enough photographer to beat what my mid-range phone can do and I'm happy not to have to lug my DSLR around very often. Part of my day job is optical metrology so I realize that traditional optical design will never fully be replaced by the smarts in our phones and the super advanced miniature lenses.

amluto 3y ago
> it's just so hard for me to imagine that those tiny, tiny apertures we have on our phones can replace a well designed lens. I don’t think they can, but they usually don’t need to. If you manage to extract a modern phone lens and stick it in front of the film of a 35mm camera or a ten-year-old digital camera, you will get utterly terrible pictures :) Nice old lenses had nice flat focal planes. For a camera phone, who cares? The depth of field is so big that you probably can’t tell whether the focal plane is flat. Nice old lenses tried hard to avoid distortion. Your camera probably corrects distortion in software. Nice old lenses collected lots of light and integrated that light using the world’s most boring algorithm: just adding it all up. Your phone has a much more sensitive sensor and cleverly takes multiple frames for you so it can infer a decent picture even in poor lighting using fancy algorithms. Really nice old lenses might have been close to diffraction limited resolution, and maybe users managed to get extremely sharp photographs with them, but they usually didn’t. Your phone camera has a much much worse diffraction limit, but it has fancy sharpening algorithms that work sort of okay, and people mostly view the photos in small formats anyway. Nice old lenses, with the aperture wide open, had shallow depths of field. Your phone camera doesn’t, and it will try to fake it for you in “portrait mode”. It looks pretty bad, but a surprisingly large number of users don’t care :) (I personally find the way hair looks to be quite annoying, and I’m surprised that I haven’t seen a nice AI-enhanced version that can fake hair over a distant background better.)
- zwieback 3y ago
  Nice summary, thanks!

amluto 3y ago

> it's just so hard for me to imagine that those tiny, tiny apertures we have on our phones can replace a well designed lens. I don’t think they can, but they usually don’t need to. If you manage to extract a modern phone lens and stick it in front of the film of a 35mm camera or a ten-year-old digital camera, you will get utterly terrible pictures :) Nice old lenses had nice flat focal planes. For a camera phone, who cares? The depth of field is so big that you probably can’t tell whether the focal plane is flat. Nice old lenses tried hard to avoid distortion. Your camera probably corrects distortion in software. Nice old lenses collected lots of light and integrated that light using the world’s most boring algorithm: just adding it all up. Your phone has a much more sensitive sensor and cleverly takes multiple frames for you so it can infer a decent picture even in poor lighting using fancy algorithms. Really nice old lenses might have been close to diffraction limited resolution, and maybe users managed to get extremely sharp photographs with them, but they usually didn’t. Your phone camera has a much much worse diffraction limit, but it has fancy sharpening algorithms that work sort of okay, and people mostly view the photos in small formats anyway. Nice old lenses, with the aperture wide open, had shallow depths of field. Your phone camera doesn’t, and it will try to fake it for you in “portrait mode”. It looks pretty bad, but a surprisingly large number of users don’t care :) (I personally find the way hair looks to be quite annoying, and I’m surprised that I haven’t seen a nice AI-enhanced version that can fake hair over a distant background better.)

zwieback 3y ago
Nice summary, thanks!