Greetings to all,

This is becoming an interesting topic of discussion. 

I Googled for the search terms 'canon raw files compression' ... and
found that there are 710,000 web pages with those search terms!

I reviewed some of those pages and found these unequivocal but
unequivalent statements ...

Since there is no 'lossy' compression, the Raw file contains the full
data presented at the camera's sensor: there are no JPEG or other
compression artifacts.

[http://www.dlcphotography.net/RawFormatWorkflow/RawFormatWorkflow.htm]

A quick glance at a folder of 150 D30 images gives sizes ranging from
2,509Kb to 4,511Kb. The RAW format does include compression (heck
on the D30 it even includes a 2/3 size JPEG of the image as well!), so
different images will compress to greater or lesser amounts. I would
guess the extremes of file size range are in the region of between 2 and 5Mb.

[http://www.binbooks.com/books/photo/i/l/57646AFA31]

Lastly, JPEG compression used in cameras is a "lossy" format meaning
that some data is lost in compressing the file. Shooting RAW allows you
to bypass this compression and retain the maximum amount of data in
your images.

[http://www.mkwphotography.com/workflow.htm]

After seeing these seemingly contradictory opinions, I wouldn't dare state
that Canon Raw format either is or is not compressed ... unless I had a
highly detailed description of the Raw format directly from Canon.

--
Martin

p.s. Yes, I have the technical background to understand the actual format
that Canon uses.