Compressed or uncompressed RAW?

Maybe it’s a bit of a beginners question. Just sold my Sony A7 and got a A7Rii (quite a change!).

I just do RAW. Shall I use compressed or uncompressed? Uncompressed has about double the size (41 / 82Mb). Question is, is it really worthwhile? Will images be better?

I did some processing with a RawTherapee 5.7 dev version and didn’t notice too much lag difference on my W10 i5 8Gb notebook. So from the PC power point of view it won’t really matter.

Is the compression lossless or lossy?

Seems it’s lossy, but seems the it’s only visible only under some circumstances, high dynamic range and low ISO.

A discussion you can find here.


Life is full of compromises, isn’t it? I shoot Nikons. Their compression is nowhere near as drastic on the file size, so I use the uncompressed. Look at it this way. Lossy compression = lost data. While that means more processing time, ultimately the end result won’t be compromised. Also, from a data storage perspective, most shots get tossed out( at least, mine do) so the good ones will have the best chance of yielding a good result.

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actually, it only means more time for disk I/O, which might be compensated by a faster decoding for the uncompressed format. Overall, I expect the impact on processing time being negligible. It might have a bigger impact on burst rates while shooting though (besides requiring more storage).


Good point, haven’t thought about that one.

Tossing out more stuff is certainly good too. I will stay uncompromising uncompressed for now.