I'm chomping at the bits over a lens I just saw. It's the Pentax 6x7 75 f2.8AL lens. Why I think I need it is another matter. I have the 75 f4.5 SMC lens but it's bigger, heavier and slower and therefore, can be a tad hard to focus when light level is low. From a sharpness perspective I don't know if one has an edge over the other. Any comments or suggestions about this?