1D4 and 5D2 Jpeg size difference

I took two almost identical pictures with both in Jpeg and Raw format.

1D4

Jpeg: 6.37
Raw: 17.6mb

5D2

Jpeg: 4mb
Raw: 22.2mb

I'm trying to work out the difference between the two Jpeg sizes, does the 1D have a larger scope for Jpeg compression?

What compression are you using for your 1d-IV, JPG? Its adjustable from 1-10, the 5d-II is only fine and course, who knows how the correspond.

Instead, take the two RAW files and convert them to JPG in DPP or Photoshop using the same settings, and check the results. That would at least be more apples to apples, in terms of compressibility of the noise and tonal gradients....

It also depends on the iso you shot at, and the contents of the scene. Shooting at low iso, with scenes that have alot of smooth repetitive tones results in pretty small files. Shooting at high iso at scenes that have alot of detail result in low JPG compression and larger files.

JC4 wrote in post #10725315
What compression are you using for your 1d-IV, JPG? Its adjustable from 1-10, the 5d-II is only fine and course, who knows how the correspond.

Instead, take the two RAW files and convert them to JPG in DPP or Photoshop using the same settings, and check the results. That would at least be more apples to apples, in terms of compressibility of the noise and tonal gradients....

I was thinking that, both cameras are at maximum setting but I changed the 1D4 up further as it was at a lower setting out of the box.

All settings were the same, ISO etc. I know there's a difference in sensor size but thought the 5D2 would have larger Jpegs.

That's it I bet. The default setting of 8 is probably a match for L-fine on the 5d-2, which will probably generate a smaller file.

I've never looked at the JPG file size. I shot JPG's on occasion, and all that matters to me is, they're not 25-35 megabytes.

My 1d4 is set to 9, for no particular reason, other than I figured 10 was probably overkill for a JPG. Had my 1d-3 set the same.

That 4 MB seems pretty small for a 5D2 22MP file -- I'd check your settings. I guess if you were shooting a white wall or a clear blue sky, a scene with no detail, maybe, or a very dark scene, but not a scene with any significant detail that I can figure.