Thank you! 
Hi Ed 
I do not know why, but this code works slightly different in Composer.
When playing it in main.lua ( no Composer ) player jumps from screenBottom (initial player position) to the centerY, and then camera follows (player is centered).
So you get nice jump simulation.
When moving code to Composer player is always (fixed) at screenBottom (player initial position).
Camera follows but it does not look nice (no jump simulation).
Any ideas why is this happening?
Maybe due to Composer sceneGroup?
I tried to insert layers.content into Composer sceneGroup (no help).
Also I have to run "** camera.tracking( player, layers.**content)" before scene:create and scene:show (otherwise following does not work).
Many many thanks!
G
I do not know what I did, but everything works fine! Case closed! Thanks Ed!