Shel wrote:
> Everything I've read recently...suggests that the filter factor for a Medium
> Yellow filter (Y2) is 2X, or 1 stop. So, while calibrating my gear
> this morning I decided to check the needed exposure compensation using
> two Pentax spotmeters, the digital Zone VI modified meter and the
> standard, but calibrated, Spotmeter V. Both showed that the needed
> exposure compensation would be about 1/3 stop more with the filter
> than without. I metered off a white truck, the overcast sky, and a
> building. Always 1/3 stop.
That has to do with the spectral response of the meters, which isn't linear.
Actual literal compensation needed is about 2/3rds stop, but yellow filters
will darken green foliage disproportionately--in shade especially--which is
why the classic recommendation is to compensate a whole stop.
--Mike
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