Apparently, pretty hard. I took pictures of sheets of Christmas lights while panning and/or rotating my Canon Digital Rebel XT. It didn’t record continuous blurry lines. Instead, I got discrete, blurry blobs. Not exactly the effect I was expecting. (Click the pictures for larger, “clearer” views of my blobs.)
I tried something similar with my cell phone’s video capabilities.
More blobs. And I feel a little dizzy. *<:-)
Oh well. Ignore Aaron’s awesome picture. This is what I intended. Yeah, that’s the ticket.