40D file size, what's going on?

I have a little problem which seems to be getting worse because I'm feeling the effect more on my business's behalf.
I have read that Fine JPEG on mean average is 3.5MB which is fair enough given brighter conditions, noise ect...
However in a bright day, my photos hardly hit 2MB. I have tried using all manual, custom and automatic modes, and the file size is rather consistent. In fact The next level down from Fine JPG the files come out at 200kb approx.

Is something wrong here? Can anybody explain this to me?

File size depends on the scene. The more randomness the picture is, the larger the file size is. If the scene is a flat blue sky and water, file size will be very small. So don't worry.

ISO also plays a part.

Low ISO = low noise = smooth tones = easily compressed.

High ISO = high noise = grainy tones with lots of false detail (the noise) that cannot be compressed.

fubarhouse wrote in post #7507392
I have a little problem which seems to be getting worse because I'm feeling the effect more on my business's behalf.
I have read that Fine JPEG on mean average is 3.5MB which is fair enough given brighter conditions, noise ect...
However in a bright day, my photos hardly hit 2MB. I have tried using all manual, custom and automatic modes, and the file size is rather consistent. In fact The next level down from Fine JPG the files come out at 200kb approx.

Is something wrong here? Can anybody explain this to me?

Agree with others. I've also noticed that the more green there is the larger the files. Maybe this is due to the fact that there are two green dots per pixel; I don't know.

How is this effecting your business?

JPEG has compression build in and will save the information is such a way to minimize duplicate information in the file. Scenary with similar color and so on will be saved as smaller images, than scenary with contrasting areas. The 3.5 MB is worst case scenario and better results such as your 2MB will be the norm.

If you are needing larger file size JPG for stock submissions, maybe shoot RAW and convert. This should result in much larger JPG files.

But, like others have already said, the size of a JPG file is a function of

• Noise - the more noise, the larger the file. Properly exposed files will have less noise and thus be smaller.
  
• Scene detail - the more detail in the scene, the larger will be the file. Large areas of similar (identical?) color will compress much more than a scene with lots of fine detail. If you shoot a huge blue sky (for example), the JPG will be quite a bit smaller than if you shoot something with lots of small areas and lots of different colors.
  

fubarhouse wrote in post #7507392
I have a little problem which seems to be getting worse because I'm feeling the effect more on my business's behalf.
I have read that Fine JPEG on mean average is 3.5MB which is fair enough given brighter conditions, noise ect...
However in a bright day, my photos hardly hit 2MB. I have tried using all manual, custom and automatic modes, and the file size is rather consistent. In fact The next level down from Fine JPG the files come out at 200kb approx.

Is something wrong here? Can anybody explain this to me?

If you have any troubles with duplicates and need to clean your harddrive, I'd recommend this photo duplicate remover. Hope it will be useful...