Originally posted by pentaxmz You simply can't argue the physics.
Really? I haven't seen you show any "physics" to argue against.
The biggest argument I've seen for in-body comes in the form of the fast primes. Canon and Nikon have few stabilized primes, and nothing like a cheap fast 50 with lens stabilization. Most of their stabilized offerings, in fact, are no faster than 2.8.
So, having a range of f/2.0 and faster lenses, plus the in body stabilization provided, makes up for any 1 stop advantage that stabilized lenses have. Plus, these fast primes are sharper and smaller than stabilized 2.8 zooms.
Overall, this means a couple of things -
1. In the cases where Nikon and Canon offer stabilized lenses, Pentax can usually come within 1 stop of their performance with a similar lens and their in-body stabilization.
2. A Pentax photographer could use primes in this instance, and gain back that stop or even more.
3. If you are shooting a Canon or Nikon and using a non-stabilized prime or zoom vs a similar Pentax, Pentax will win hands down by 2-3 stops vs the non-stabilized cameras.
Pentax has a compelling system. There are advantages and disadvantages, but I find that for the dollar conscious Pentax is a hard one to beat. Even for those with surplus funds, Pentax stays competitive.
Sorry to rant- but you can't just throw "physics" out there and call it a day. I'm currently majoring in physics, and when you try to do things like that to win arguments, it makes science sad.