In article <33C8067C.2B7@bc.sympatico.ca>, Fred_Wilsenack@bc.sympatico.ca says...

>I know that using a polarizing filter costs you between 1.5 and 2 stops.
>Does an AF SLR with TTL metering compensate for this automatically, or do
>I have to manually make up the difference? What about other types of
>filters, e.g. ND, coloured, star, etc?

Any of the neutral-colored filters (polarizer, ND, star, etc.) will be
read properly by the camera TTL meter (though for various reasons, you
may want to alter the exposure...). Colored filters are a different
story (the camera instruction book notwithstanding...;-), and do
generally require compensation (with Nikon, +1/2 stop with dark yellow,
+1 stop with orange, and +1 1/2 with red). To check this for yourself,
meter an evenly-lit large grey surface without a filter. Apply the
filter factor correction for filter absorption (included in the
instruction sheet with the filter) to the camera controls (generally +1
stop for dark yellow, +2 stops for orange, +3 stops for red) when putting
on the appropriate filter. Take a reading through the filter, and shift
the compensation dial or ASA until the meter indicates correct exposure
(assuming the light did not change on the grey surface, and you are
reading it from the same angle...) - you will probably find that the
compensations recommended above must be applied for the TTL meter to
give the correct exposure (with the filter factor for the filter
applied to the no-filter exposure).
Hope This Helps
(David Ruether - http://www.fcinet.com/ruether )