Filesize of CR2, DNG and lossy DNG

[Ralf F]

Hello,

I did some testing on the filesize of CR2, DNG and lossy DNG with my Canon 5D Mark IV.

I made 30 photos and saved them as RAW (6720 x 4480) and Medium RAW (5040 x 3360) on the SD and CF card in my camera.
Canon 5D Mark IV has an SD and CF slot, there you can save the photos in different formats.

Now I compared the file size of these RAWs.

As expected the version with the higher resolution are larger than the medium version.

Then I converted these CR2s in Lightroom Classic in DNGs (non lossy).

File size for the full size CR2s went down, but the file size for the medium size CR2s went up by nearly 50%.

Has anybody ever seen this with his photos?

In a second test I converted the CR2s in lossy DNGs, here the file size droped significantly.

Also the full RAWs are larger than the medium RAWs. 

The shown filesize is the total for 30 photos

Ralf

I use Lightroom Classic (LrC 11.3) / Photoshop (Ps 23.2.2) / Lightroom (Lr 5.2) with Creative Cloud on a MacBook Pro (15-inch, 2017, Intel Core i7 / 16GB / 500GB SSD) with macOS Monterey Version 12.3.1

[Todd Shaner]

Canon 5D MKIV mRaw and sRAW files are already demosaiced and reconstructed by manufacturer's camera firmware, which may account for the DNG file size difference.