Thanks Neuro. I have never shot anything below f2.8, so please elaborate on using the 3 stop ND, would I still over expose if I had the shutter at 1/8000th of a sec?
A 3 stop ND would get you back to shutter speeds that you would be used to using your 70-200 II outside in bright light. Let's say that with a f/2.8 lens you find yourself at 1/4000s at ISO 100. The 85L II at f/1.2 would require shutter speeds at around 1/20000s, which is beyond the limit of the camera, so the exposure is blown. The 3 stop ND would get you back down to shutter speeds between 1/2000 and 1/4000.
Just my two cents and a question at the end:
I have the 70-200 II and the 135L, and for cost reason I went for the 85 1.4 Siggy after good suggestions here. To me I wanted both fixed focals, in addition to the heavy 70-200, as I see that there are situations where I need the 85 over the 135 (although the latter is my favorite of all lenses). For instance when taking pictures in a party/wedding moving among guests, where when using the 135 gets impeded by other guest walking in between you and your subject. I got great reccomendations on this forum for the Siggy 85, and I like that lens very much. However, I borrowed the 85 1.2 this summer (and somenone here told me kindly that I should avoid at all cost to shot in AI Focus, and to shot in One Shot instead, something I now do, having given me an exponential growth in keepers. I love the bokeh of the 1.2, and I think I will have to start saving for it, and maybe keep the Siggy or sell it.
Then my question: I found it interesting to read that on a bright sunny day, the camera must use a shutterspeed at 1/20000 of a second to get the right exposure and not blow it away. Is this specific for this lens, or would this apply to the 50 1.2 too?