So I'm comparing the Nikon D5000 and the D90 for a good entry level DSLR. What I need some help on is regarding the placement of the auto focus motor.
My understanding is that the D5000 requires lenses which have the motor built into the lens itself (Nikon labels those AF-S lenses if I'm not mistaken...?). The D90 on the other hand has the auto focus motor in the body. Because the technology used in the bodies is always changing (improving for the most part), I've heard it's always good to spend the real money on sharp/fast/etc glass, rather than jumping for the most expensive body because pretty soon another better one will be released. If I were to get either the D90 or the D5000, I would be building two different lens catalogs depending on my decision-- if I went the D5000 route, all of my lenses would have motors in them, and if I went the D90 route they wouldn't. So my impression is that if I ever upgraded to a nicer body down the road, it would most likely already have a motor in it, and if I go the D90 route, I would be able to use all of those lenses on the improved technology of a better body. If I go the D5000 route, I would need to buy a whole new set of lenses when I upgraded to a nicer body (that presumably has a motor in it already)....is this correct? If so then wouldn't it make the most sense for me to chose the D90 over the D5000 because the lenses I buy for it will fit perfectly on a nicer body if I decide to get one in the future?
One more question...
Third party lenses like sigma...where is the motor in most of them? If I wanted to keep my options open I'd like to go with a the body that has the most selection outside of nikkor.
Thanks in advance for your help!!!
Elby