Ralf is not properly explaining what is happening. The tip does not ever "stay too long" on the cue ball.
http://www.youtube.com/watch?v=WxzNT5_Fc20
Think of a jump shot as any other shot. The difference is that this time you are approaching the ball from an elevated angle.
The center of the cue ball on the outer edge or a better way to say it - the equator - is now at an angle to bed of the table instead of roughly parallel to it. Now to clear a blocking ball the MINIMUM angle you need IS the angle that represents the lowest clear path over the blocking ball.
The closer the two balls the sharper or steeper this angle will be.
The second thing you will need to know is how much force to apply. There is also a minimum amount that is needed and is learned through practice. Force is used to land the cue ball closer or farther from the blocking ball. In this way you can very precisely place the cue ball on a jump shot.
When you approach the shot you should approach it with center ball - no matter what your angle of aproach is. When you are looking down at the ball divide it into two halves and the diving line is the center.
Now, you can point the cue tip a little below center and give the cue ball reverse or back spin, or you can go a litle above center and give the cue ball forward or follow. You can also add any other side spin that you wish to from this point.
Now, whether using the dart stroke or the pendulum stroke you want to shoot the shot as you would any other with a smooth stroke and follow through. You will quickly find out the minimum force you need to make the cue ball jump over the object ball.
Things to be careful of are excess movement.
These are common mistakes that derail an otherwise perfect set up.
1. When using the pendulum stroke you lunge forward. This cause the tip to dip below where you were pointing it and leads to miscues.
2. When using the pendulum stroke you push you hand down on the final stroke which lifts the tip up.
3. You pull your hand into or away from your body on the final stroke which again pulls the tip off the point you were targeting.
4. You grip the cue with your fingers overlapping the top and thus inhibit a full stroke. This causes the stroke to be too short and causes the stroke to be distorted as well.
5. On the dart stroke you pull you hand down on the final stroke or lunge forward - both of these actions will pull the tip off line.
Basically you need to see the bridge as a fulcrum point. If you are at the proper point to address the cueball then any other movement will pull the tip off the point you are aiming at anf while you may achieve the jumping portion of the shot it's quite likely that you won't achieve the precision placement or desired result.
90% of the problems with jumping balls is due to a faulty stroke, not following through and not stroking straight on the delivery. The other 10% are due to not fully understanding which angle and force to use.
It is a VAST misconception that one cannot control the cueball on a jump shot. It is a commonly taught idea that hitting the object ball is the goal.
It is not. The goal is to shoot the cue ball in a controlled manner in order to achieve a precise (as precise as possible) result. This is the same as any other shot.
Mnorwood, your video reinforces this assertion that making the cueball jump and hitting the ball is enough. The rather forceful admonition against following through will hamper rather than facilitate success on this shot.
And success is defined by me as controlling the cue ball not just whacking and hoping.
I always start my demonstrations by telling everyone that the jump cue is not a magic wand. It is a cue stick with one special property that used properly will facilitate and expand one's range of jump shots. Used improperly it will cause a lot of games to be lost through cue ball fouls and giving up the table with easy shots for the opponent.
I teach precision jumping starting with a proper stroke foundation.