Canon 70D does provide 3 options of getting raw images - Small, Medium and Raw. I would like to know whats the difference between 3. Recently i did my tour and got some very good results from medium raw images. Would like to know the following things 1. I do understand size of the image varies in the 3 cases and what is the extent of information loss in Full vs Medium Raw 2. Which option to use in what condition. 3. Didn't look like 70D did any software processing in case of any of the raw images but does it w.r.t Medium and Small Raw
The only "real" RAW option is the option RAW. The other two, S-RAW and M-RAW where introduced in the EOS-1D Mark III and EOS-1D Mark IV respectively as options to decrease the file size. The S-RAW has about 1/4th the number of pixels and half the fil size of "real" RAW and the M-RAW about 54-60 % of the pixels and two thirds of the size of the RAW option.
The use of the S-RAW and M-RAW is of course if you want to save storage space (not really a problem these days), if your memory card/camera combination can't keep up with the data flow from continuous shooting or if you have to transfer many images over a limited data link in a short period of time all while still retaining the larger bit depth compared to shooting in JPEG.
As far as Canon has documented the formats publicly there are no processing applied to these two formats except from lowering pixel count compared to the RAW option
Canon has a good information page about the formats if you want to take a look yourself.