Pinkie vibrato in high positions
I have a lot of trouble with pinkie vibrato in high positions (5+). My pinkie is not short, but relative to my third finger, the tip barely makes it to the last knuckle of the third finger. I guess you could say it is deep set on my hand. On top of that, my pinkie is rather slender and I don’t have much tip/pad real estate to work with. Once I’m in 5th or higher position, the last knuckle of my pinkie finger does not flex. All my other fingers are fine in this regard, just my fourth. In these high positions, the only semblance of vibrato from my 4th finger is literally the skin on the tip stretching and pulling with the motion. Ive usually just avoided my pinkie in these positions and either shifted to use another finger or extended the third. Any tips or tricks if you’ve seen this before?
vibrato with the pinky is more difficult, no question about that. you can try to avoid the pinky on important notes but sometimes that creates other problems so every violinist needs to work daily for a minute or two on pinky vibrato. anyway, rest assured you are not alone. having said that, I am puzzled by your saying that the final joint of the pinky is not flexible beyond 5th position. so in lower position it is nice and flexible but not in higher positions? that has probably to do with your hand position, bring up the hand a bit higher so that you can vibrato more "from the top" so to speak. anyway that final joint must be flexible or there is no question of vibrato! actually that last statement is too strong, like you mention yourself, some people do a "skin vibrato" with the pinky, where the pinky is just completely straight and you move the hand back and forth keeping the pinky in place and using the skin to get a vibrato effect. some really good violinists do that, I remember a video by a Eastern European violinists some time ago here on v.com but I cannot find it back.
I have a short pinky and a wide-shouldered viola, so I have to find various ways of keeping the pinky curved enough to allow intonation adjustments and vibrato. But yes, "skin" vibrato works, though viola strings need a firmer hold than violin strings. And in the highest positions it is not always necessary (or advisable) to hold the string right down on the fingerboard.
I think your pinky joint sounds like that of most of us normal people. It's amazing to watch many of those soloists who have those incredible flexing joints. Like Jean, I'd say keep working on it. Sometimes my students have a rigid pinky because the left elbow isn't far around enough, which forces the 3rd and 4th fingers to be straight in high positions. Perhaps investigate whether your hand really is around the neck enough (via the elbow) so that the 4th finger remains curved. That can help.
For vibrato on any finger, try to only touch the fingerboard/neck with the thumb and the finger that you are using. Having an extra finger down is like trying to vibrate on a double-stop. The 4th finger vibrato is always narrower then the others. For important top notes use the third. The third finger normally reaches farther than the fourth, in the high positions, but, the 4th f. can do extensions with the first down, and the second and third off.
1) Try to use less finger pressure to stop the string when you're in high positions. Use only as much pressure as you need to produce the sound you want, not a bit more. People emphasize left hand finger strength but you may not need a stronger 4th finger but a more flexible one.