Continuous Low and Continuous High enable burst mode shooting. That is, your Nikon d5300 records a continuous series of images for as long as you hold down the shutter button, making it easier to capture fast-paced action.
Here’s how the two modes differ:
Continuous Low: The camera can capture as many as 3 frames per second (fps).
Continuous High: Records as many as 5 fps, depending on the Image Quality setting. If you select the Image Quality setting that produces 14-bit RAW (NEF) files, the maximum frame rate is 4 fps.
A few critical details about these two Release modes:
You can't use flash. Continuous mode doesn’t work with flash because the time that the flash needs to recycle between shots slows down the capture rate too much. If flash is enabled, you get one shot per each press of the shutter button, as in Single Frame mode.
Images are stored temporarily in the memory buffer. The camera has some internal memory — a buffer — where it stores picture data until it has time to record all the photos in a burst of shots to the memory card. The number of pictures the buffer can hold depends on certain camera settings, such as Image Quality.
When you press the shutter button halfway, the shots-remaining value in the lower-right corner of the viewfinder and Live View display changes to show an estimate of how many pictures will fit in the buffer.
After shooting a burst of images, wait for the memory card access light to go out before turning off the camera. (The light is in the lower-right corner of the camera back, just below the Delete button.) That’s your signal that the camera has moved all data from the buffer to the memory card. Turning off the camera before that happens may corrupt the image file.
Your mileage may vary. The number of frames per second depends on several factors, including shutter speed. To achieve the highest rate, the shutter speed must be 1/250 second or faster. Additionally, although you can capture as many as 100 frames in a single burst, the frame rate can drop if the buffer gets full.
Continuous Low is enough for all but the fastest action. Unless you’re shooting a subject that’s moving really fast, not much changes between frames when you shoot at 5 fps. So, when you use Continuous High, you typically wind up with lots of shots that show the exact same thing. Continuous Low usually gives you plenty of frames to capture the shot without the unnecessary file bloat.