I was experimenting with HDR photography with my Nikon D7000. I consulted an article on how to do it and the results look great. However, the settings on the Nikon seem to allow for a minimum of 1 second between shots. This means that taking a three exposure HDR series takes several seconds (especially with the mirror lock-up). I've seen examples of action shots using HDR photography and clearly several seconds isn't remotely suitable. In fact, several seconds is so long that it can only be used in the most still conditions. Is there any way to reduce this time or am I out of luck? If I'm out of luck, what features am I missing on my camera?
What I do on my D90 is use the normal self timer, which you can set up to take multiple shots.
I don't use mirror up. That seems to be the limiting feature when using the interval timer technique in the article you referenced.
I would use mirror up for very close macro shots to eliminate any movement. I wouldn't bother with landscapes, as I don't feel it really makes any noticeable difference. I've read opinions both ways. It's probably best practice, but I think a lot of people feel it doesn't make enough difference to bother.
If you need quick shots (moving clouds say) then I'd do away with mirror lockup if that's indeed the limiting factor. If you can afford 1 second intervals, then go ahead and use mirror lockup. I'd say do some tests and see if you can tell the difference though.
You can also do cropping in the action shots to apply HDR to the remainder of the scene, while the action area stays with the on exposure that is best for it. The water ripple shot looks to me as if this was done. The bike flip shot may have as well (no sky detail right around the bike in the air). There's no reason the subject of interest has to actually be in every shot; it only needs to have itself at the right exposure.
For practice, set up a shot at a scene which would benefit from HDR, but also has people walking past in the scene. Shoot the background over your HDR bracket. Then set the exposure that is right for exposing the people that cross the scene. When someone does walk by, don't just take a shot ... take multiple shots. Then crop that person into the scene multiple times. You would just be combining a couple techniques in post processing. Then you should be able to see that HDR is effectively a supplement to the subject.
Another fun shot is to make one of those "family profile" shots where all the kids gather first on one side of the parents, then again on the other side. In post processing, in addition to the HDR in the background (shoot that without the people even there) the family is now larger (if the parents are still enough, this is very easy to do).