Future

[RedGoblinz]

Im considering on getting the D3100, but the lack of AF-S motor is discouraging me as i want lenses with AF there for me when I need it. It seems like AF-S lenses are more expensive , which won't be a happy thing since im only a teen and don't have "income".

But thinking the other models use screw-type autofocus, is this slower because it doesnt involve things like USM with Canon?

What happens if you use an AF-S lens on a D90? What happens with the screw thing

[OsmosisStudios]

The list of AF-D lenses is shrinking quickly, and the only lens currently on the market with both an AF-D and AF-S options is the 50mm f/1.8 (though the 60mm f/2.8 macro is close). That gap will likely be erased by 2012.

[Almond.Butterscotch]

Originally Posted by OsmosisStudios

the only lens currently on the market with both an AF-D and AF-S options is the 50mm f/1.8 (though the 60mm f/2.8 macro is close).

And the 85mm f/1.4. And the 50mm f/1.4.

[OsmosisStudios]

I stand corrected. The big issue for most is cost, though, which is why I mentioned the 50/1.8

[Aegea]

Originally Posted by RedGoblinz

But thinking the other models use screw-type autofocus, is this slower because it doesnt involve things like USM with Canon?

What happens if you use an AF-S lens on a D90? What happens with the screw thing

Screw focus is generally slower than AF-S, though there are exceptions. The slower focus may or may not be an issue depending on the lens and what you are photographing.

When you use an AF-S lens on a camera body with a built-in motor, the lens motor takes precedence - the screw drive doesn't do anything.