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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

PrasadChuri
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  • http://cpn.canon-europe.com/content/education/infobank/image_compression/file_types_raw_sraw_and_jpeg.do – clabacchio Oct 10 '14 at 08:22
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    @FredP Please don't use comments for answers. – Philip Kendall Oct 10 '14 at 08:38
  • @FredP that's an interesting thing to consider about reducing noise on a smaller format – laurencemadill Oct 10 '14 at 08:41
  • @PhilipKendall Sorry, it's not really a documented and complete answer, hence the comment... But I will stop if it's not well tolerated. – FredP Oct 10 '14 at 09:07
  • @laurencemadill I don't know how the smaller format RAW data is produced from the full sensor data, maybe someone can confirm or infirm my idea. – FredP Oct 10 '14 at 09:11
  • @FredP Generally, posting chatty speculation as a comment is bad, because with distracts from the question and comes above real answers that may follow. Comments are best for asking for clarification (to be deleted if that is then added to the question), for references to other questions that might be relevant, and for very short factual statements that are unlikely to false. – mattdm Oct 10 '14 at 12:28
  • Think about it this way: if you post speculation as an answer, it can be voted up if true or down if not true, an commented on or edited as a means of others helping it become a real answer. None of those things can happen with comments that need improvement, and they take up the space that should be used for improving the question. – mattdm Oct 10 '14 at 12:31

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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.

Hugo
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