I learned a great lesson today,  READ THE CAMERA MANUAL!!.  During a recent trip up to Maine to photograph osprey in flight, I became quite frustrated with the autofocus system on my camera not being able to keep up with the fast pace of birds in flight.  This was a new adventure for me and I was not experienced with tracking the subjects in the frame or setting the camera for this type of photography.    The basic problem was as soon as I lost track of the bird, the lens would focus to infinity and then it was all over getting the bird in focus.  After reading the manual I have realised that I could set the camera software to overcome this.  This mornings photography with smaller birds was very successful with a much higher keep rate.   I am sure custom software settings applies for all camera brands  to optimise autofocus performance.  I was very surprised how many custom settings were available (over 6) to improve autofocus on my Pentax which is not known for high speed autofocus to support sports and nature photography.  The current settings make the camera very usable for this type of photography.  Here is an example of todays results using a robin (not glamorous but much sharper):