What are the main differences between a jazz Pianist and a classical Pianist, If there are any. If I play mainly songs of pop artists (e.g: The Beatles, David Bowie, Elton John, etc.) does this count as a jazz pianist? What is easier to learn when you start learning piano at an "old" age (20+)
Jazz and classical music have different traditions and points of focus. In classical music the distinction between composer (or creator of music) and performer is highly divided - only in specific instances is the performer allowed to improvise (in the historical practice of music from the Renaissance, Baroque, classical piano concertos by Mozart and others, and certain 20th/21st century classical music). In jazz, the roles are much more closely integrated, and the main focus of this art is improvisation and embellishment upon standard tunes (this again discounts the most modern developments). Accordingly, classical music has a much stronger focus on notated music, while jazz is more focused on using chords to describe a work.
Playing the music of pop artists falls somewhere in between - most performers in this style can play based on chords, but the sense of improvisation is usually not as rigorous or important - in fact, it's often important the melody remain largely the same. In addition, jazz is very focused on extended tonal relationships, meaning that the piece can change keys in a single measure. This rarely happens in pop music, which tends to focus on one or two related keys.
None is necessarily easier, but if you don't know a ton about theory, jazz might seem pretty daunting. Classical performance focuses less on this aspect, but technique is often very important. With that in mind, pop music is probably the best place to start.
Jazz is a collective, public and free art. You can train yourself alone, in private, up to a certain point, but a jazz pianist is someone who plays piano with other musicians (sometimes they are only there through their musical legacy): the improvisation component is the important point, not the themes or they origin.
In fact jazz artists use any theme from any source and transform them, reinterpret them, mock them, rock them or magnify them. You can do jazz with a little excerpt of Beethoven or Chopin, the Beatles or the latest broadway musical, as well as your own musical ideas, pre-cooked or not.
There is a lot of material on the net, fabulous records, more and more jazz transcriptions and classical scores. But the best way to learn, jazz or classical, is to find people more experienced than you are (teacher or not) and interact with them. It is perhaps easier to find official teachers for classical piano technique or around classical repertoire. More and more colleges and conservatories have jazz cursus. Looking at classified ads or going to local places where jazz pianists use to play you may find someone to help you.
This is an interesting question.
I learnt the nuts and bolts of playing the piano by doing 'classical' so I can read music etc, but now I play almost entirely jazz and 'popular' music.
Without going into too much detail I find that the two disciplines require you to think about your instrument -- and the music -- in very different ways. When I'm playing a jazz gig, I'm not really thinking about the mechanics of playing (ok, that might be partly becuase I haven't ingrained them already) but I'm more just concentrating on very deep listening -- on the moment and on what the other musicians are doing.
I do know that classical is probably better for raw technique, but for general playing in the real world -- in bands, playing by ear, and being able to comp along with virtually anything -- then the knowledge required to play jazz takes you into another place of freedom altogether. I no longer have to buy sheet music for anything - I can play virtually anything I want by ear. And properly, not just one-finger stuff. Within 10 or 15 mintues of getting it under my fingers, it's there. Only playing classical music will never give you that ability and it requires a completely different way of approaching the notion of 'competent' playing.