Live tethering from Canon 5D Mark II to Macbook Pro with Lightroom 3/4. I like to be able to have the tethering software grab the files from the CF card inside the camera, as opposed to the buffer. On the 5D Mark II, the internal buffer is about 9-11 shots. While doing rapid fire when NOT tethered, the camera will write to the internal CF card and clear the buffer in about 3-4 seconds. While tethered, the same 9-11 shots will take about 50 seconds to transfer entirely to the Macbook Pro with Lightroom 3/4. During the 50 seconds, the amount of new photos that can be taken is limited to how much the camera's internal buffer has been cleared up. That is, if 10 seconds has passed and only two images have been transferred over, then only 2 more new images can be taken. Whereas if Lightroom was pulling from the CF card inside the camera, then Lightroom can take as much time as it needs via USB2 while the camera's entire buffer is empty within 3-4 seconds.