On this video tutorial by Lynda, Adobe expert Deke McClelland demonstrates how to take any object with a shadow and move it into a different background image in Photoshop.
McClelland demonstrates how to use the blend mode to multiply and mask the ball (this tutorial actually doesn’t show how to mask a more complex object such as hair). The end result does seem to look good in terms of the shadow but do keep in mind that a shadow is just a small part of making a realistic image of this sort (a lot has to do with the different lighting on the background and your subject – and our eyes are very sensitive to these kind of differences as you can see in the video).
If you want a more in-depth look at how to use blending layers, we highly recommend that you watch Jesús Ramirez great video on “Understanding Blending Modes in Photoshop“.
You can find many more Photoshop video tutorials on LensVid’s Photoshop section.