Simple math.
There are 24 bits per pixel (3 channels times 8-bits).
The resolution of a 5D is 4386 x 2920 for a total of 12,807,120 pixels.
12,807,120 x 24 = 307,370,880 total bits.
Since there are 8 bits in a byte the file is 38,421,360 bytes (307,370,880 /
.
There are 1024 bytes in a kilobyte (KB) so 38,421,360 / 1024 = 37,520.859 KB
One Megabyte is 1024 KB so the final file size of an uncompressed 12.8MP tiff file is... *drum-roll*
36.641464 Megabytes.