Panasonic Lumix DMC-FZ200 User Manual page 84

The further away from the camera the subject is the smaller amount of
motion is needed by the focus lens/motor.
The nearer the subject is to the camera more movement of the focus
lens/motor is needed. If the rate of distance change exceeds the rate at
which the opto-mechanical system can keep pace with the focus will not
be achieved resulting in the subject being out of focus (not to be
confused with subject motion blur which is due to too low a shutter
speed)
One way to speed up focus performance is to keep the AF/AF Macro/
Manual switch on the lens barrel set to AF when you are shooting at
distances beyond 2 metres.
In this configuration the lens is set to be limited at 2 metres which
prevents it having to cycle all the way from 1 metre position in the AF
Macro mode.
Between 1 metre and 2 metre is a long focus movement for the focus
motor/lens and this takes appreciable time.
Chart Showing Subject Velocity and Lens to Subject Distance Limits
Speed of target Km/Hr towards or receding
100
10
1
1 2 3 4 5 6 7 8 9 10 11 12 metres
Distance to subject
I do not have access to the actual figures for the FZ200 but the above
chart is taken from a entry level dslr and shows quite clearly that at 2
metres from the subject the camera can only track a moving subject with
a velocity of 0-1 Km/Hr otherwise the mechanism cannot change position
quick enough to stay in focus.
I guess you can appreciate now that tracking flying birds at close range is
probably beyond the rate at which the FZ200 can react.
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