why file sizes vary

[Un dbutant]

from 4mb to 6 mb to 11 mb
all with the same 20mpix and flash
the 11mb is for shots of my room door
boring brown teak door
and the manual book also mentions only 151 pix for 2gb sd card = 13mb per pic
but why the huge range? 4 to 6 to 11mb in real life shots?

 

[AndricD]

jpeg is a compression format - diferent shots will compress to diferent sizes based on many factors including colour variance and how many solid blocks of colour there are

 

[viking79]

Un dbutant wrote:

from 4mb to 6 mb to 11 mb
all with the same 20mpix and flash
the 11mb is for shots of my room door
boring brown teak door
and the manual book also mentions only 151 pix for 2gb sd card = 13mb per pic
but why the huge range? 4 to 6 to 11mb in real life shots?

Compression, low noise shots without as much detail will be smaller, and shots of complicated scenes and at high ISO will be much larger. Subjects like the sky compress better.

Eric