The answer is yes, but, although movie mode still feels a little tacked-on, it is significantly improved over existing Nikon DSLRs. The biggest difference it that the camera can now use its contrast-detection autofocus system while shooting movies (by setting Liveview mode to 'Tripod'). We'd recommend using an external microphone if you're likely to use this features, since the noise of the camera or lens autofocusing can be heard on the movies. It's also worth noting that, even when using lenses with Nikon's ultrasonic AF-S motors, focusing isn't particularly snappy, so will have to be worked into videos as an 'effect,' rather than an annoyance.
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http://www.dpreview.com/reviews/nikond300s/page19.asp