[JJ_SO]

BTW, the SD quattro has an IR filter "far" in front of the sensor.

Thus no anti-dust shaker, right ?

Infrared it is? Didn't know that but saw it, too. Don't know about dust removement functions, so far I've only experience with fixed lens Sigmas.

Any experience with the "sealing" ?

Hmmm, I would not bet much on that. Even if the body would be sealed, then

1. there's still no description, against what exactly the seals should do a good job - weather we have all day...
   
2. the lenses which have some kind of seals, are to be found in the "Sports" group. 120-300/2.8 and 150-600/5.6-6.3 is kind of not much wide angle