Burst Mode refers to any SLR’s ability to shoot continuous images, while the shutter is being held down.
Burst Rate or Maximum Burst Rate as it is often referred to on camera manuals, are terms used specifically for digital SLR cameras and refer to the maximum number of images that can be captured continuously before the internal buffer is ttemporarily filled and the shutter release is locked preventing further exposures.
Once the buffer has room, by way of finishing writing the images being processed onto the memory card, the shutter release is unlocked and further images can be captured.
Burst Rate can also be explained in terms of the amount of shots left before you have to wait for the camera to catch up with you.
Think of the entire process as walking a fast dog. Your ambition and drive to take lots of photos is the fast dog, and your camera is the person walking it, but sometimes the dog goes too fast and you have to tell him to hold on and give you time to catch up.
Burst Rate/Burst Mode are often confused with frames per second on a DSLR. Here’s the difference.
Frames per second are part of a DSLR’s AF Drive function. Think of AF Drive as driving a car because that is what it really is.
When you drive a car, you get to determine how fast you want to go. With a camera’s AF Drive, you have a few options of how fast you want the camera to take pictures.
You have a high speed continuous mode, a low speed continuous mode, and single shooting. On a Canon 7d, high speed offers 8 shots per second, low speed 3, and single 1.
With regards to the difference between AF Drive and Burst Rate/Burst Mode, AF Drive only takes into account the maximum number of shots that can be taken in a second, while Burst Rate/Burst Mode calculates it for as long as the camera can continue to take photos continuously independent of time but rather, storage capacity and performance.
What this means, is that Burst Rate/Burst Mode will have a direct correlation with the image format chosen: JPG or RAW, the resolution: high, medium, or low, and the speed of the memory card and its capacity.