Camera Labs

I have just purchased a 7D body and was out experimenting with it just taking shots of parks, trees, landscapes etc.
I was quite astonished at the image size I have been getting, in the region of 25Mbyte, the same as my 5D MK II. So I decided to take the same shot with both cameras/lens and it confirmed they are very similar sizes. Considering the difference in the 7D and 5D MK II camera sensors 18Mp and 21Mp respectively.
Both cameras are set up for RAW only images, (not sRAW or mRAW).
The image size is from the camera info and also from PS5/Camera Raw.
Most of the literature and 7D videos I have seen suggest 18Mbyte images so just wondered why I am getting such high image size from a smaller sensor.

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5DMKII, 7D, 50D, (EF17-40-L-USM) (EF24-105-f4L-IS-USM) ( EF100-f2.8L-IS-USM) ( SIGMA 15mm f/2.8 EX DG Diagonal Fisheye ) (SIGMA 50mm f/1.4 EX DG HSM)

Don't confuse MP with MB. Canon uses 14-bit processing. So for a 18MP sensor, that is an uncompressed raw output size of about 32MB. They do seem to employ some kind of compression (I don't know if it is lossy or lossless) so the filesize does typically vary depending on content, but 25MP is about reasonable in my experience. The slightly higher MP count of the 5D2 should result in a similarly bigger size if all else is equal.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Hi PoPo.

Sorry the above should read Mbyte and not Mpx where I was referring to file size. I have corrected the post.
I was just a bit astonished at the file size compared to the 5D. I was either expecting a much smaller file size from the 7D or a larger file size from the 5D.
Considering their different sensor sizes.

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5DMKII, 7D, 50D, (EF17-40-L-USM) (EF24-105-f4L-IS-USM) ( EF100-f2.8L-IS-USM) ( SIGMA 15mm f/2.8 EX DG Diagonal Fisheye ) (SIGMA 50mm f/1.4 EX DG HSM)