>>3875003The point of a pancake is to be flat. The circumference really doesn't make much of a difference--unless the circumference is, like, bigger than the camera body, it really doesn't matter to the overall size of the camera+lens package.
But even so, even if you calculate the overall volume: The Canon EF 40/2.8 is still smaller than most of the Pentax M line of lenses. Yeah, it's got a slightly larger diameter, but overall volume is still smaller.
If you want to prove me wrong about that, I've given you the link with dimensions for all of the Pentax lenses in that line, the Canon's dimensions are easily googlable as well, and I trust you can also find the formula for the volume of a cylinder. Go make a spreadsheet and report back with your results.
