10d and tamron 28-75 question

Hey gang..My 10d should be here today and Im probably going to pick up a tamron 28-75..I was hoping someone could answer a question that I have??

I notice on the canon af lenses that there is no aperture ring..but on the tamron there is an aperture ring? How does the camera control the aperture of the lens. Can the camera change the aperture independant of the aperture ring when your operating in auto mode?

Thanks for any help, I know this is a stupid question but I am totally new to dslrs...

Steve

Ok, I just found out that the tamron has no aperture ring..Sorry for waisting the bandsbpace.

Steve

Actually the aperture rings went out of fashion with the FD lens line (auto-focus/auto-exposure) with everything being controlled via the camera.

I have this combo (as well as the 20D and a Tamron 17-35 F2.8-4 lens) and it is a good deal.

Enjoy,