Gecko and Dehk, thanks
I have been away from this thread for a few days, and Did Not heed your advice related to contact cleaners, etc.
My sequence with this problem was to check both release buttons (L+R), and the electronic release on the pistol grip, with all forms of shutter release the problem is consistent (shutter will normally fire only if lens is stopped-down prior to release).
In trying to further my research, I put the lens in "A" mode to see what would happen. Mystically the problem disappears and the shutter fires normally, so my guess is that there is some electrical malfunction between the lens and the body circuitry (shutter fires normally if lens is in A mode or stopped-down prior to exposure). And in the first post, I mentioned that the 150mm lens operates normally, so I would think that it is a Lens issue vs. the body. Keep the comments coming, I don't think this is a common SLX problem but I would think someone has heard of this issue in the past.
Originally Posted by smiling gecko