Different Canon cameras offer next to RAW also M-RAW and S-RAW. These file formats feature a lower resolution but also a significantly smaller file size.

Is it possible to shoot RAW files with all their advantages and convert them into M-RAW or S-RAW files later, if there is no need for full resolution in a subset of photos? Is there software available for this task?


1 Answer 1


It's theoretically possible to do so but I doubt any software implements this currently.


mRAW and sRAW are both ways to compress images that attempt to preserve as much if the editing latitude as possible. If you've decided a group of images aren't worth preserving in RAW but you have processed them then JPEG is a much better space saving strategy preserving both resolution and image quality (but not editing latitude).

The desire to convert to m/sRAW at a later date just doesn't make sense to me: you've decided that a set of images are not worth preserving at RAW filesizes & printing at high resolution, but you want to preserve the ability to change your mind about white balance at a later date. If you think you might reprocess images to make them better then it seems worth investing in small increase in storage space to keep the original RAWs.

  • \$\begingroup\$ I keep all my RAW files, they are not removed in favour of their JPEG output. I want to keep smaller versions of some RAW files without losing editing capabilities. They might be edited at a later date, but not e.g. for high resolution prints. This makes sense to me for a significant part of my family photos. ;-) \$\endgroup\$
    – lejonet
    Jan 13, 2014 at 20:39
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    \$\begingroup\$ Having used m/sRAW for a while back when I first purchased my 7D, the editing latitude is really not that much more than your average TIFF. In some respects, given that m/sRAW are 14-bit encoded, they actually have less. A standard RAW image has VASTLY superior editing latitude than any of mRAW, sRAW, or TIFF. If one wishes to save space, use of m/sRAW is a great way to do it, but if you need editing latitude, I highly recommend against using either. \$\endgroup\$
    – jrista
    Jan 14, 2014 at 21:05
  • \$\begingroup\$ @lejonet With the current cost of disk space (which is only falling too), is there any point? 1Tb/$50 hard drive will store approx 33,000 30Mpx RAW files, so perhaps 120,000 sRAW. how many photos a year do you take? \$\endgroup\$
    – Steve Ives
    Sep 28, 2016 at 14:14
  • \$\begingroup\$ Another use case: I am a photography teacher with a computer lab full of underpowered computers (with no graphics cards). I would love to teach my students the benefits of RAW, but my computers cannot handle files that large, so I am forced to have them shoot jpeg instead. In this case the learning process is more important than the benefits of having an image with large dimensions. \$\endgroup\$ Apr 4, 2023 at 12:55

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