The two I posted were both shot with a Nikon D3. The top one used a Nikon 70-200 VR f/2.8 lens; the bottom one used a Carl Zeiss 50mm f/1.4 lens.
The shallow depth of field 'separates' the subjects from the back/foregrounds, i.e. it makes anything that isn't in the same plane as the Jeep appear out of focus, or 'blurred'.
The Carl Zeiss lenses in particular (I also use an 85mm f1.4 sometimes) have a very buttery 'bokeh' (term for the out-of-focus areas) and exceptional color saturation/contrast.
The result is a 'look' that 'normal' digital cameras can't replicate. For $6k, the pictures better look special, eh?
(Professional photography is one of my various 'occupations')
Here's another Zeiss example, this one of my 06 Midnight Blue Unlimited