Is this done by the camera or Photoshop?

http://www.dphoto.us/forumphotos/data/1271/IMG_9762web.jpg

http://www.dphoto.us/forumphotos/showphoto.php?photo=27204

Thanks!

Photoshop. It could be done in-camera, but would require a dark background (like the night sky, or like black velvet in a studio) otherwise the exposures wouldn't be right. In this case, either the subject would be exposed correctly but the background would be overexposed because you shot it several times or vice-versa.

By putting it against a dark background, you could leave the shutter open and stop the subject at different spots by hitting him with a flash. This is pretty difficult to do, and one wrong flash would ruin the shot. Photoshop makes stuff like this easier.

Steve's dead-on, but just to add, if this was done in camera each rider would be transparent because the space where he was a moment before would now also have the background exposed onto it.

This one obviously had a very fast continuos fire shutter....

True about what Seb said. And it must have been a very fast camera! That's a wide lens too - I wonder if it was that Nikon 10.5 fisheye. Nikon Capture has a way to correct the fisheye distortion and spread out the sides so you get a huge angle of view. On the shots I've seen done that way, the sides look a little more "stretched" than here though.

How would one go about creatin this sort of image? I'm guessing it would be using layers, but.... how? :D

One of the images in the series is the base layer, and each additional image is layered above it with everything byt the subject masked out. You cut out the rider from each image and put it over the base layer, if that sounds any simpler. :)