I've been having fun recently with a plug-in for Aperture which is meant to mimmick the effect of a tilt-shift lens. This is useful if you do not own a real tilt-shift lens, or if photographing in situations where the real tilt-shift lens would be difficult or inappropriate. In my case, both apply. For one, I do not own a Tilt-Shift lens. And in this situation it would not be very desirable to use anyway. This was shot with a 200mm focal length (you can't get telephoto tilt-shift lenses in the first place!) at a relatively slow shutter speed to show some motion in the wheels and the background. And it was shot from a somewhat high vantage point, about 20 feet above the track surface. The high vantage point (higher would have been better) and the large amount of background in the shot made this an ideal candidate for the tilt-shift effect.
The tell-tale sign of a Tilt-Shift is that it should give the shot a bit of a miniaturization effect, making the scene look like a model rather than real-life. This effect gets amplified with higher vantage points. Next time I need to bring a ladder to the track! :) The other tell tale signs are the very shallow depth of field (which could come from a large aperture) that is not parallel to the film plane (which you cannot get from a normal lens). In the case above the plane-of-focus is tilted in the direction the car is travelling, sloping up from bottom left to middle right. An unusually large amount of saturation and contrast is thrown in, and a bit of vignette as well. And voila. Thoughts? The car's owner was thrilled. :)
Not all shots lend itself to this treatment, but those that do often turn out great!