Subject rotation

Subject rotation is the name I give to a blurring phenomenon that occurs when only one section of the bike is moving in tandem with the movement of the camera. You’ll see it demonstrated when bikes fly around corners. Here the front wheel moves away from the camera, the rear wheel moves towards the camera, but the centre of the bike (with the biker) tracks relatively steadily with the camera, meaning the centre is in focus, but the front and rear wheels are slightly blurred. It’s very hard to correct for this and doing so takes a lot of practice – if in doubt, make your shutter speed faster to reduce this effect.