Canon CR3 vs CR2: what changed

A photographer with a 5D Mark IV and a photographer with an R6 shoot Canon RAW, and their files have almost nothing in common under the hood. CR2 is a TIFF. CR3 is a video style container with a new compression codec. That single change is why a tool that opened CR2 for a decade shrugs at CR3, and why "Canon RAW support" on a box means less than it used to.

Which bodies write which

CR2 arrived with the EOS-1D Mark II in 2004 and carried every Canon DSLR for fourteen years: the 5D through the 5D Mark IV, 6D and 6D Mark II, 7D, the 80D, every Rebel, the 1D X Mark II. CR3 arrived with the EOS M50 in 2018. Every mirrorless Canon since writes it: R, RP, R5, R6, R6 Mark II, R3, R7, R8, R10, R50, R100, R5 Mark II, R1. The last DSLRs, the 90D, 250D and 850D, write CR3 too, so the split is by date, not by mirror. If the body is from 2018 or later, it is CR3.

What changed inside the file

A CR2 is a TIFF. The first image directory holds a full size JPEG, the second a thumbnail, the third the sensor data compressed with lossless JPEG. Anything that reads TIFF can at least find the preview, which is why CR2 previews showed up in Explorer and Finder years before the sensor data did. A CR3 is an ISO base media file, the family MP4 belongs to. Canon metadata sits in a private box, the previews in their own boxes, and the sensor data is compressed with Canon's own CRX codec, which had to be reverse engineered before any third party could decode it. The embedded JPEG is still full size on the R series, so a viewer that understands the container can show a CR3 instantly. A viewer that expects a TIFF cannot even find it.

C-RAW and the 40 percent

CR3 bodies offer C-RAW, a lossy compressed mode that saves roughly 40 percent of the file size. It replaced sRAW and mRAW, which shrank the pixel count instead. C-RAW keeps the full resolution and throws away precision in a way Canon tuned to be invisible at normal exposures; the cost shows up as slightly noisier deep shadows when you push a file hard. For weddings and events at sane ISOs it is a reasonable trade for a card that lasts the day. For landscape work you plan to pull three stops out of, shoot full RAW.

What opens a CR3 today

Current versions of macOS, Windows with the Raw Image Extension, Lightroom, Capture One and every serious editor read CR3 now. The trouble is "current": an older Mac that cannot update, a client's laptop, a studio machine nobody touches, or a body newer than the decoder. For those, Kepla's CR3 to JPG converter opens the file in a browser tab with its own LibRaw build, CRX decoder included. The full size preview shows in under a second, a develop from the sensor data takes a few seconds, and the file never leaves the machine. Canon's free Digital Photo Professional remains the reference render for the exact Picture Style, if you can stand the wait. Opening RAW without Photoshop covers the rest of the map.

And if the CR3s are a whole wedding rather than one file, the question is not opening them but clearing them. Kepla for Mac reads the embedded preview on every frame, opens the RAW only where the answer needs it, and hands you a clean set with the reason on every frame it set aside. Request Founding Access.

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