No problem, just strange behavior with CF card

[mbaginy]

I shoot raw with my Canon 5D, saved on a 8 GB SanDisk Extreme III CF card.  Newly formatted card shows capacity for 498 images.

Three weeks ago I photographed at my friend's wedding.  Somehow, the 5D managed to cram 603 images onto (into?) the CF card!  I'll not complain but would like to understand the phenomenon.  Is the capacity shown on the monitor wrong?  Am I really shooting at ISO 100?  Have I really set aperture to 5.6?  I'm not really questioning all settings but this CF card capacity experienced has left me stumped.

Has anyone else noticed similar behavior?  Or can anyone offer an explanation?

[Alan Smallbone]

There is nothing wrong with the card. The number of pictures left is a guess by the camera, each raw file will have a different size depending on the amount of detail and how complex color wise the picture is and also ISO will affect it. So what you saw was that the pictures were able to fit into a slightly smaller package.

Alan

[mbaginy]

Alan, that makes complete sense.  Don't know why I didn't think of it.  In fact, I've never really view the image file sizes.  Went for a walk today and returned with some 200 images.  Reading your reply, I searched for them in the finder (Mac) via LR4 and saw, they range in size from 9.9 to 15.9 MB.

Yes, the CF capacity topic makes sense to me now.  Thanks for your explanation!!