Jpeg file size 6D vs 60D

[6Dnewbie]

Hi all,

Being a bit newer at all this I'm sure there is something I don't know that I don't know  which would answer this:

Been taking some identical test shots on my new 6D and my old 60D to compare.  Jpeg only for now, same "quality" setting.    I noticed that the file sizes of the pictures on the 60D were larger than the 6D's.  I would have thought that with a larger sensor and roughly 2mp more the 6D's would have been the larger, or at least the same.  Some of the 60d's were almost 3-4 mb larger.  

Lenses if it matters:  6D 24-105L kit, 60D EFS 15-85 IS.   ISO was the same in some, apetures pretty close in most.

What am I missing? 

[cicopo]

I'm no expert in this but unless you framed the shots the same it may come down to how much certain areas were similar enough to store the needed info using higher compression. You can see what I mean by taking a photo of a busy scene & then of the sky. The busy scene will be the larger file because more info must be stored compared to the large identical areas of sky.

[cicopo]

One other thing that I think makes a noticeable difference is whether noise reduction is turned on or off in the menues. It can also affect how fast the buffer writes to your card.

[6Dnewbie]

Thanks for the response.

Good point on the noise reduction, I'll check those settings to see if they are on the same setting.

I tried to frame the shots exactly the same, using only the center AF point focused on the same point for both.   Got them pretty close.

I came across a 6D review that had a table showing the raw file sizes for various cameras at various ISO's, and it showed the 60d and 6d pretty similar (still not understanding why given larger sensor and 2 more mpixel) .  The 60D's got larger at the higher ISO.  I am guessing increased noise may be the reason?