What is the relationship between burst mode and shutter speed?

Question

I shoot macro and recently have been interested in focus stacking, however with live subjects this becomes quite a challenge. Thus I'm exploring how burst mode actually works.

What does the limit on burst-mode of my camera actually mean? -I'm guessing this is more of a continuous processing limit. As I presume at higher shutter speeds with enough lighting, I could exhaust the same limit much faster.

Question: Does burst-mode on a higher shutter speeds, enable me to capture more pictures?

Camera: Nikon D3200, 4.5fps at burst.(honestly feels more like 1.5- 2 fps by ear.)

Answer 1

In good light, your shutter speed will be something like a hundredth of a second (or less), so it's basically negligible in the limitations of continuous-drive. There's some inherent limits from moving the mirror and resetting the shutter, but the primary limits are processing time and writing the data.

It takes some time to read the sensor data and to convert it into JPEG. This is usually quite fast (in fact, in cameras in the past half-decade, it's basically a non-issue), but if you enable features like in-camera distortion correction, the overhead can be higher.

Second, writing to the memory card itself can be slow. If you're getting much below the rated framerate of your camera, I'd check to see if a faster card will help. Of course, if you exceed the camera's other limits (including limits of the data connection), that won't help. You can also try reducing the amount of data you write: JPEG is (much) smaller than RAW, so that usually helps (the writing is orders of magnitude slower than the conversion), and of course RAW+JPEG is the slowest. You might even experiment with lower-resolution JPEGs to see if that helps,

Answer 2

Burst mode does not enable your camera to have a higher frame rate.

It does seem possible that in full auto mode, software might use the signal that a user has entered burst mode as a signal that biases other settings toward shorter exposures, but this won't exceed the capacity of the camera that you could set in manual mode.

One use case for burst mode is actually in situations where the shutter speed is on the slow side and there is no alternative handy to physically pressing the shutter button (but with burst, the vibrations and motion associated with the initial press are gone after that first exposure).

If you want to increase shutter speed and maintain proper exposure, consider increasing your sensitivity (higher ISO number, note this will also increase noise), increasing your aperture width (lower f-number), and/or adding light to the scene.