How Apple Photos handles RAW files
Jul 28, 2018 13:58:40 #
John_F wrote:
One way of telling is to check the file size. My camera manual claims the pixel depth to be 14 bits, so a 6,000 pixel by 4,000 pixel image should be 6000x4000x14/8 bytes in size. The 42 MB is actually the minimum file size as the file header contain other information. Any file size that is less than the calculated minimum can not be a RAW file.
Actually you are wrong, raw files are usually written using lossless compression. That is when uncompressed the values are what they should be.
jpeg compression is lossy so the re-inflated file is similar to the file before it was compressed but not identical.
With jpeg this tends to become noticeable in sky which may show some banding.
I think there are some sony raw files that can use lossy compression. If you care to take a photo with the lens cap on you should see the raw file for that photo is relatively small.
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