It sounds as if you are filling up the buffer... does this occur after taking a continous burst of shots at a high frame rate?
If so, there's a limit, after which the camera has to slow down or pause to off-load the images onto the memory card. If shooting RAW + JPEG, this is most likely to fill the buffer and slow the camera most quickly. Try just shooting RAW alone. And, since they are smaller files, shooting JPEG alone also allows more shots before the camera has to slow during continuous shooting.
Another possibility.... It also might slow down if you memory card is less than ideal. 60D use SD memory cards, which I'm not terribly familiar with... hopefully someone else can recommend what's optimal for your camera.
There also are some settings that slow down the camera. For example, if shooting long exposures with Long Exposure Noise Reduction enabled, the camera actually takes two shots of equal duration. The first is your exposure, the second is a blank shot (with the shutter closed) that the camera will use to identify noise it will automatically deduct from the first exposure. If you cancel the second exposure before it's completed (such as by turning off the camera), both images will be discarded.
Some focusing methods and settings also can cause the camera to pause.
***********
Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM
