Well, with the 50mm the problem was I was shooting in A mode with an M lens, switch to manual and problem disappears, great! Except now I've got to learn how to work out shutter speeds (I always shoot aperture priority)
I did manage 100 shots today with it in auto, which was fantastic, then it started its flop problem again, and then another problem cropped up, yay.
Whilst experimenting with my manual fisheye, the k-r did it's other party-piece of releasing the shutter with every key press, I've had this before but it rectified itself after being powered off, not this time! 5 minutes off this, removing batteries before searching here, suggestion of remove lens, hold shutter tab at side of mirror down, remove battery, power back-up didn't work for me, so I held it in place and released the shutter a few times till it worked!!!!!
They say its a sticky shutter tab, but doesn't apply to me, this must be electrical. Which I sort of already knew.
So this brings me back to my sigma 50-200, why do I have this problem with this lens, and why only zoomed in?
Also, if there's any way to cover the contacts when using my M 50mm and RETAIN aperture priority function, that'd be great