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It's not just that. The lens itself doesn't have enough resolving power. When light passes through a tiny aperture, it becomes irreversibly blurred, enough to b

It's not just that. The lens itself doesn't have enough resolving power. When light passes through a tiny aperture, it becomes irreversibly blurred, enough to be detected by the micron-scale pixels in the camera sensor. Camera phones will try to re-sharpen the image, but some information is always lost. It's especially obvious looking at things with fine detail and sharp edges, like tree leaves against a bright sky.

pdpi 7y ago
"The lens is sufficiently prone to diffraction that you won't get the full value out of the sensor's resolution" is a very different statement from "the sensor's resolution is not really 12MP". Saying "The camera isn't true 12MP" suggests the latter, not the former.
- jerf 7y ago
  I deliberately stayed away from claiming a cause in my post, because I don't know the cause. I only know the result of the system as a whole; every cell phone camera I've had in the last 10 years does not actually take pictures at its claimed resolution, even in broad daylight. (I can also say it can't solely be over-aggressive JPG-ification, because the result doesn't match that; the 'blobs' I refer to cross the JPEG DCT boundaries freely. I can't say bad JPEG-ification isn't part of the problem, though.) I tend to buy last year's midgrade phone because I don't really need the latest and greatest. Maybe the top end really does take the full photos they claim, but that still leaves a lot of cell phones that are lying. Most of the recent cell phones take perfectly adequate pictures, considering the amazing disadvantages they are laboring under. It's just that if you downsample the pictures to 2 or 4MP, you're basically losing no information. (There are similar effects with video. The aforementioned 10+ year-old camera I had suffers from this as well. It has a "720P" and a "1080P" video mode, but based on my experimentation, both modes get real video out at about 400-500 "real" lines of vertical quality. I can squeeze either video's source down to that size and when I compare the full screen result to the original, I can find no difference whatsoever. I imagine more modern real cameras probably do a better job here; this thing is pretty old now, obviously.)
- jacobush 7y ago
  Not very.

pdpi 7y ago

"The lens is sufficiently prone to diffraction that you won't get the full value out of the sensor's resolution" is a very different statement from "the sensor's resolution is not really 12MP". Saying "The camera isn't true 12MP" suggests the latter, not the former.

jerf 7y ago
I deliberately stayed away from claiming a cause in my post, because I don't know the cause. I only know the result of the system as a whole; every cell phone camera I've had in the last 10 years does not actually take pictures at its claimed resolution, even in broad daylight. (I can also say it can't solely be over-aggressive JPG-ification, because the result doesn't match that; the 'blobs' I refer to cross the JPEG DCT boundaries freely. I can't say bad JPEG-ification isn't part of the problem, though.) I tend to buy last year's midgrade phone because I don't really need the latest and greatest. Maybe the top end really does take the full photos they claim, but that still leaves a lot of cell phones that are lying. Most of the recent cell phones take perfectly adequate pictures, considering the amazing disadvantages they are laboring under. It's just that if you downsample the pictures to 2 or 4MP, you're basically losing no information. (There are similar effects with video. The aforementioned 10+ year-old camera I had suffers from this as well. It has a "720P" and a "1080P" video mode, but based on my experimentation, both modes get real video out at about 400-500 "real" lines of vertical quality. I can squeeze either video's source down to that size and when I compare the full screen result to the original, I can find no difference whatsoever. I imagine more modern real cameras probably do a better job here; this thing is pretty old now, obviously.)
jacobush 7y ago
Not very.