was going thru my brother's stash of camera parts yesterday and came across a sigma 28-80 D macro lens. cleaned it up and tried hooking it up to my D80. In Autofocus mode i can hear the lens trying to focus, but it doesn't seem to be doing anything.
while trying to manually focus it, it offers alot of resistance compared to when its off the camera body. why??????
tried surfing the web for some info as to why this happens. Is it because its a D lens? or its just backward compatibility issues coz it's a third party lens? or maybe the lens has seen better days.
Help! its really bugging me.