i did a quick telly up of all the professional advertising photographers i know (im friends with quite a few), and i would say half have changed to or about change to nikon.
i would too, but im not a fan of nikon lenses, and am waiting eagerly for a better sensored higher res camera than my very disappointing 5dmk3.
Everyone is always "about to change"... what percentage actually did change? Not just giving you a hard time... it's a good point. Advertising photographers really do have value in the higher resolution and there's a few on this forum that are also "about to change to MF if Canon doesn't put out a higher res body soon". Their reason being that price has come down on MF digital backs to make the leap but they will stay with Canon for cost, ergonomics, lenses, etc. IF a higher res body comes out.
I know eight photographers that have changed.
a couple were old nikon lovers, but many had never owned a nikon digital camera before. the couple of architecture photographers I know that own canons for the 17TE lens (which is outstanding) haven't moved because of that, but one of them has been testing the d800 and is impressed- comparing it to his aptus 75s back with both res and latitude.
These guys tend to shoot medium format with alpas, but there are plent of situations they need to shoot architecture but cant get the full authority (think china), so if they had a high MP canon with the 17te they can sneak great quality shots without looking much different than a tourist.
One guy I know who shoots a pile of very famous big billboard and displays changed from contax/phase to d800.
Hes says is more important to shoot a higher volume than have a few more megapixels. the d800 apparently has enough to retire his medium format back
thats the real reason i want more megapixels- i want all the speed of a dslr and higher iso than my contax phase p65+ so i can retire that and make my life easier. unless you are a tripod/ static shooter, medium format is a pain in the ass to use.
if you see on my site (www.paulrossjones.com
), i shoot open a lot, and my clients often demand medium format files sizes, but i want to shoot the speed of a dslr.
a high MP canon would solve this for me.