AF while in continuous frame advance mode/burst mode

I am curious to know the answer to this. It could apply to just about any camera out there but, since I own and shoot a D90 I will ask it here.

While in continuous frame advance mode, or burst mode, does the AF system continue to focus, or track, the subject?

For example, when I press the shutter button I know the viewfinder goes dark while the mirror is up for that brief fraction of a second. But I wonder, does the AF sensors depend on the mirror as the viewfinder does or do the sensors continue to see the target even though I cannot?

When shooting in burst mode I'm usually in continuous servo mode because it's usually in an action situation such as shooting sports. But to answer your question no. The light needs to hit the mirror to be bounced up into the area where the auto focus occurs. Shooting in burst mode the mirror never returns till you release the shutter release button.
In fact the light meter is disabled as well.

FastGlass said:

When shooting in burst mode I'm usually in continuous servo mode because it's usually in an action situation such as shooting sports. But to answer your question no. The light needs to hit the mirror to be bounced up into the area where the auto focus occurs. Shooting in burst mode the mirror never returns till you release the shutter release button.
In fact the light meter is disabled as well.

Click to expand...

That may answer part of my question, but now it brings another.

Are you certain the mirror stays up during continuous frame advance mode?

If the AF does not continue to work while the mirror is up then how does burst mode continue to get focused shots? The subject is moving so the focus would have to change or you would have several of your successive shots out of focus.

This is why I ask this question. When shooting birds in flight I notice that the subject stays in focus even though it has moved possibly away from me or even towards me. If the AF did not continue to work I would not have focused shots.

I am just making sure this is the way it works or it is is all just according to luck.

The mirror does return for a split second between each frame in a continuous burst. It is in this very brief moment that metering and focusing occurs. In more advanced models the autofocus system is able to predict the subject speed/direction so that you get more in-focus images. The D4 will shoot 10fps with metering and Af between each frame, or 11fps with metering and focus locked.

LensWork said:

The mirror does return for a split second between each frame in a continuous burst. It is in this very brief moment that metering and focusing occurs. In more advanced models the autofocus system is able to predict the subject speed/direction so that you get more in-focus images. The D4 will shoot 10fps with metering and Af between each frame, or 11fps with metering and focus locked.

Click to expand...

Really. I was sure I read somewhere that it didn't. I believed it seeing how burst happens so fast the mirror didn't have enough time to go through the process each and every time. Learn something new every day.