Canon R5: Resolution vs. File Size

Mar 01, 2021

This is the first post in a short series about our switch from DSLR to full frame mirrorless, specifically the Canon R5. Switching cameras can have small and big impacts on your workflows - and we will be exploring these in relation to the different headshot services we offer. Like many, I've been calling this camera a game-changer, and for good reason.


Efficiency: Where it counts

We all want to be efficient, especially when it comes to our headshot gigs. Being "efficient" means "achieving maximum productivity with minimum wasted effort or expense."

That includes: achieving maximum resolution with minimum file size.

When it comes to high-volume or event headshots, it's important to find the sweet spot between a reasonable file size and enough resolution for flexibility (cropping, etc.). It's not very efficient to have to deal with massive image file sizes if we don't really need all the resolution that comes with it. Exporting at 2048 pixels (on the long edge) is typical for our events, but for high-volume gigs, you'll usually want to deliver in higher resolution.

But what if we could get a lot of resolution, without the massive file sizes? That would be something!

When you don't shoot high-volume headshots, it doesn't really matter how big your file sizes are, since you're probably not taxing your CPU or filling up hard drive space with low quantities of images. Photography forums are filled with people saying things like, "just keep everything on the maximum settings all time. You pay for a fancy camera that makes big files, let it!" But as soon as you're delivering headshot to large numbers of people, every MB is multiplied by hundreds or thousands. Now it matters!

To be clear: MP (Megapixels) is referring to resolution - how many pixels you have to play with. MB (Megabytes) is referring to file size - how much hard drive space you need.

When we relied on DSLR's as our main workhorses (up until late 2020), it was pretty straight forward. We shot full RAW for just about everything except event headshots, where we typically switched the 5D Mark IV into Medium RAW (M-RAW). Shooting in Full RAW gave us a hefty 30 MP image, but an equally big file size. Dropping down to M-RAW resulted in 25% less pixels (23MP) but a 43% smaller file size. We shot many events, each with hundreds of people per day (= thousands of images) with M-RAW which averaged out at 20MB/file. (Note: We noticed a slight difference in image quality when using M-RAW but it wasn't enough to deter us from using it).

Enter the R5

Now what do we do with this beast of a camera that has 50% more pixels than the 5D Mark IV, coming in at 45MP? Isn't it unmanageable? Especially for event headshots? The first thing to know is the the Canon R series of cameras don't offer medium or small RAW. So what can you do?

Enter C-RAW

Canon introduced C-RAW (Compressed RAW) with the M50 and the .CR3 file format back in 2018. In a nutshell, C-RAW is a lossy, compressed RAW file, but in practice it is almost identical in every way to a full RAW image. There are many tests on the internet comparing RAW vs C-RAW. Almost everyone will say the quality difference is practically unnoticeable (if you didn't know which image was shot in C-RAW), unless the image was many stops underexposed and you had to employ drastic shadow recovery. Even then the difference wasn't huge. But for giving up a tiny bit of recovery flexibility what do you gain?

In our back to back test, switching the camera from RAW to C-RAW saved me just shy of 60% in file size (from 41MB to 17MB!) The difference really depends on what you are shooting and your camera settings. Expect a 40-60% reduction across a variety of shooting conditions using C-RAW. This massive drop in file size was shocking as we were still shooting 45MP images and they were a smaller file size than the 23MP M-RAW images on the 5D4.

What voodoo is Canon using in these new cameras?

Disclaimer: We wanted to compare files from both cameras, with different RAW options. To keep a level playing field we looked at previous images, and shot new images that were as similar to each other as possible but understand that image size varies significantly based on detail, light, ISO, and other factors. Our tests, although not scientific, were downright practical and taken from actual headshots shot on a dark grey background at f8, 1/160, 160 ISO. Your results may, and probably will vary. But you'll see a very similar trend.

Enter Crop Mode

So what if ~17MB files still seem too big? (hint: it's not, we have shot many thousands of images at events that were ~20MB and over and the computer could keep up) Well, you can switch the R5 to 1.6 Crop Mode which drops your resolution from 45MP down to 17MP with a resulting file size of ~8MB. 17MP is still big enough for event headshots. In Crop Mode your image dimensions will be 5088 x 3392 on the R5. 8MB C-RAW's are very small. You'll save 80% vs. shooting full uncompressed RAW. The big downside is that your image will be tighter than you are used to since the image is cropped like a 1.6 Crop sensor (think Rebel series). Your 70mm lens now performs like a 112mm lens - so you'll need a wider focal length to shoot the same field of view in Crop Mode. This may be a deal breaker for you, or you'll simply use a different focal length. (Note: The R6 Crop Mode is only 7.7 MP so you'll still be able to squeeze out a 2048 pixel image, but just.)


A lot of numbers were mentioned, but the summary is this: If you have an R series Canon camera, go ahead and switch to C-RAW, certainly for high-volume and event headshots. If you have the R5 and want the absolute smallest RAW file size, set your camera to C-RAW Crop Mode.

We started by looking for the most efficient combination of resolution vs. image size - and the winner would be the R5 set to C-RAW. It offers the highest resolution with the next to smallest file size in our side-by-side comparison.

We trust this helps you get the most out of your camera's RAW settings when it comes to shooting headshots!

Products mentioned: Canon R5, Canon R6, Canon 5D Mark IV (affiliate links)