[lonjil]

> Why make the distinction if there is no difference?

There is a difference, which is that the compressed lossless version is smaller and requires some amount of processing time to actually be compressed or uncompressed. But there is zero difference in the raw camera data. After decompression, it is identical.

> If a computer compresses and expands the image using an algorithm you are not getting back the same image. Period. I do not care if you perceive it to be the same, it is not the same.

It is the same. You can check each and every bit one by one, and they will all be identical.

[spider-mario]

Careful, next they’re going to argue that once you copy the raw files off the SD card, they’re not the same images anymore.

[FollowingTheDao]

If you copy something, by definition, it is not the same file. It is a copy of the file not the original file.

If you copy a Van Gogh is it worth the same as the original?

[spider-mario]

No, but it’s also a painting instead of a digital file, so different considerations apply (maybe the copy wouldn’t be strictly identical, maybe the value is affected by “knowing that Van Gogh is the one who applied the paint to the canvas” or by the fact that only one such copy exist), and this is therefore a false analogy.

If you copy the number written on a piece of paper to another piece of paper, is it the same number? Yes, it is, and a digital photograph is defined by the numbers that make it up. Once you have two identical copies of a file, what difference does it make which one you read the numbers from?

Or are you arguing that when the camera writes those numbers to the raw file, it’s already a different image than was read from the sensor? After all, they were in volatile memory before a copy was written to the SD card.

[FollowingTheDao]

Thank you. How can something be different and the same?

[lonjil]

One aspect may change (file size) while another remains the same (the actual data you get when you read the file).