The correct way to determine a filter factor is to photograph an 18% grey
card with and with out the filter. Then measure the density of each image
and determine the LogE difference from the D-logE curve you would get from
the process because how you process is important. Now who is going to do
that? Meter reading is Kentucky windage. Works for me as I get older.
Dave
Since I don't know what brand meter you have or its age, let me warn that trying to determine your own filter factor is iffy because your meter's sensor may not be equally sensitive to all wavelengths. This was a problem years ago when SLR's first started including meters. Metering with the filter in place often produced the wrong exposure. Today's meters have a better spectral response.
Jerry
-----Original Message----- From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Shannon Stoney Sent: Friday, September 29, 2006 3:09 PM To: pure-silver@xxxxxxxxxxxxx Subject: [pure-silver] filter factor
I just bought a Hoya yellow K2 filter for a view camera lens. (Luckily it also fits my medium format camera.) I held it up in front of the spot meter today while metering shadow areas, and it read a third of a stop less than without the filter. So, does that mean my filter factor is 1.3?
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