QUOTE(iamKiet @ Jul 4 2010, 10:07 AM)
For Sony,the lenses designed for APS-C sensor have the "DT" in the name,as long as you see "DT" in any Sony lenses,then it's APS-C lens,and those without it,is FF lens.
Most of the Minolta old lenses are FF lens (perhaps all? I not sure about this,someone please clarify,thanks)
Yes,APS-C lens can be used in Sony A850/A900,but the body will crop the image to APS-C sensor size automatically.
And yes,FF lenses can be used in APS-C camera,good example is Minolta old lenses such as beercan/50mm f1.7,or Sony 16-35Z f2.8

But the focal length will be different in APS-C bodies,with the factor of 1.5x (for sony bodies),example for Minolta 50mm,the focal length is 50mm in A850/A900,where as for other APS-C bodies,the focal length is 75mm

QUOTE(wingster @ Jul 4 2010, 10:08 AM)
In Sony yes, all APS-C will able to fit on FF camera but it gives you an very dark vignetting field because the APS-C lens, the glass itself were not design to cover the coverage of FF sensor field so the result will crop the image down as the APS-C size
On the other hand all FF-Lens were able to fit in APS-C camera this is because the glass itself were fully coverage on 35mm sensor so it will definitely fit on smaller APS-C sensor
Thanks for the educate.. appreciate
Oh yes, just order An A550 from Sony centre as have promotion with 3 yrs warranty..@ RM2350 body / RM2460 with kit lens.