Same Quality at Half the Size: How Good Is Canon's New Compressed Raw Format?

The majority of photographers shoot raw files because the larger file sizes over JPEG are offset by the big gains in post-processing flexibility. Nonetheless, companies are always doing what they can to give photographers options for smaller file sizes with minimal quality loss, with the latest from Canon being the Compressed Raw format on their new mirrorless cameras. This great video takes a look at how these files hold up against traditional raw files and if you should switch the feature on.

Coming to you from Alex Barrera, this excellent video takes a look at Canon's new Compressed Raw format. If you have shot with the EOS R or EOS RP cameras, you may have noticed that they use a new file format (CR3) and that you have the option of saving files in Compressed Raw. This format will generally save about 40-50% in file size, which offers a substantial gain in storage and can make life a lot easier if you frequently come home with large batches of images. Not only will this make things like storage and backup easier, but it will also give you gains in buffer usage when shooting. On the other hand, the disadvantage of compression is that it can often result in image quality loss, but you might be surprised by just how good Canon's version is — so much so that you might just prefer to leave the option turned on at all times unless you are really performing extreme edits. Check out the video above for Barrera's full thoughts.

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20 Comments
LA M's picture

Asked and answered years ago...in fact you can find that same info on Canon's website since the 5D MKII days

Mike Clare's picture

This cRAW format may be being confused with the older Canon option of mRAW, which is a smaller pixel-dimension file in the raw format. This new file is the same full pixel dimension of the sensor but with some form of compression algorithm to create a smaller file size. I believe other camera manufacturers have had compression options for raw files, but this (I believe) is Canon's first option (ie. not available back in the 5D MKII days).

LA M's picture

It's an evolution of the same thing...sheesh. There is little to no difference. I shot xRAW for weddings most of the time because it saved space and printed albums just as well..

Must be a slow news day?

Alex Cooke's picture

No, it's not an evolution of the same thing. In the past, Canon raw file sizes were reduced simply by cutting resolution. This is something entirely different for their cameras: reducing file size while maintaining full resolution and for all intents and purposes, the same file quality.

LA M's picture

Wrong. Doesn't matter what marketing mumbo jumbo they spin. It's the same thing... Don't take my word for it. Compare a 5D MKII the same way. NO difference in IQ.

Deleted Account's picture

Alex holds an M.S. in Applied Mathematics; you declare it's just "marketing mumbo jumbo". I just don't know who has more credibility...

Tom Reichner's picture

LAM, you are severely mistaken. C-RAW does not reduce the resolution the way previous RAW options did. C_RAW is a full resolution option, with the only difference being the way that the pixels are grouped so that the file size can be smaller.

Perhaps you could learn about something before you go writing posts, so that you will not make yourself look ignorant.

sam dasso's picture

Kind of funny. Early Sony A7 cameras used compressed RAW. They got trashed by purists and they added uncompressed RAW option. Now Canon went in other direction and it is a great accomplishment. For people who don't use SONY - SONY compressed RAW is indistinguishable from uncompressed. You have to make special setup that doesn't happen in real life to find a difference.

Thatcher Freeman's picture

I don't own a Sony but it seems like their compressed RAW has been criticised because it had obvious compression artifacts in certain scenarios. The examples from the first article when I googled it (link below) seems to have pretty glaring artifacts if when zoomed in, and on real-world examples.

https://stephenbayphotography.com/blog/sony-raw-compression-artifacts-re...

The way you framed it, it sounds like your experience is different from what this guy said. Is the author of this linked article using the wrong settings or something?

Halvor Evensen's picture

Hi Thatcher,

I did see some artifacts when pushing my previous A7III by recovering 2-3 stops, but it was very minor. However with that camera I mostly shot uncompressed since the files weren’t that big. Other than that I would probably call it an even after watching this video, up to two stops.

However the A7r iv is a different story for me. I struggle to see any artifacts at all and I have tested it in multiple situations. The only time where I can spot the difference is with astro, and those high contrast scenes is where u probably would want to have it set to uncompressed.

It’s just my personal experience. But it is fantastic that we can save space on our memory cards and storage :)

Greetings from Norway

Thatcher Freeman's picture

Thanks, nice to see your experience that the compressed RAWs from Sony cameras have a minimal compromise in image quality. Competition in the space improves cameras for everyone, and that's certainly a necessary feature with the high resolutions of the a7r cameras.

sam dasso's picture

Yes, my experience is different. I don.t try to recover shadows on 0.5MP crop from 42mp file.

Thatcher Freeman's picture

To be fair, if you were using one of the lower resolution Sonys then these kinds of artifacts would be larger, particularly if you did not have the option of an uncompressed RAW. With Sony's modern a7r offerings the benefits of the smaller file size really start to outweigh the shrinking artifacts though.

I'm thinking I'm about five years late to this discussion lol

Christian Durand's picture

here comes the Sony fans ....

Colin Robertson's picture

Is there a new compressed raw format I'm not aware of? The EOS R has been out for like, a year and a half and I don't think it was the first camera that included C-Raw (just the first canon I have that has it).

Tony Tumminello's picture

I believe it was introduced with the M50, so it's been out for a couple of years now at this point.

Mutley Dastardly's picture

When there is a difference it's no lossless compression. Why don't you compare it at a high iso?

Lennart Böwering's picture

I'd like to know how cRAW compares to the compressed dng. I did a lot of testing and now compress pretty much all of my images, because it's still plenty enough and saves me more than 50% drive space.
So if these two compare, I'd be very happy to use it if I ever change to a canon mirrorless.

Spy Black's picture

Tastes just like margarine. No difference...

Tom Reichner's picture

Sounds great! I wish that C-RAW was available on my 5D4.