Originally posted by lol101 Rectangle is for tone curve, hexagon is for color space.
Yes, this is the favourite guess by now.
But would a 645D have such a button? And if so, wouldn't it be an open hexagon rather than a filled one?
When pressing the Fn button, you had a choice of 5 selections:
- Custom image (an open hexagon)
- Drive mode (a rectangle)
- WB
- ISO
- Flash
WB and Flash are still there, ISO has moved as button to another location. Drive mode got the timer symbol as a button (and I assume that bracketing now is a drive mode).
Custom image is a menu item on the K-m. So, it is indeed the one missing button from the Fn functions anyway.