<p>Thank you very much to everyone. You have helped me and I have re read all your responses a couple of times.<br>
I now understand the way the metering is being displayed. To summarise, in P mode when flash attached, camera automatically sets to 1/60th (minimum) and displays the light deficiency expected to be filled by the flash. From experience, I agree with the criticism of P mode for flash. I note that if the D300 metering is set to centre weighted or matrix the SB600 flash sets itself to iTTL-BL whereas if the metering is set to spot the SB600 sets itself to iTTL. In situation where there is too much difference between dark and light the balanced option fails to light the subject sufficiently. This is why I was getting subject under exposure.<br>
Better practice is to spot meter on subject using S, A or M mode where flash is necessary to capture an acceptable image of the subject. Balanced fill flash (in P mode) acceptable where rendering of low lights (under the eyes for example) could be improved with use of a little extra artificial light, the difference between available light and the extra lighting required not being that great.<br>
Please feel free to correct me or let me know off your approach as would really appreciate it. The context is social family photography. Thank you all again. <br>
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