Filter factor

[RobertP]

I picked up a Tiffen orange #15. I think this is the older version of what now is their #16. When I meter through it with a pentax spot meter it shows a correction of 2/3 of a stop. I called tiffen to get a filter factor and they told me 1 2/3 stops. Could there be that much difference between what they claim and what my meter is telling me? Thanks, Robert

 

[Nick Zentena]

A #15 is a dark yellow. A #16 is a light orange.

Did they tell you a filter factor of 1 2/3? or 1 2/3 stops? A filter factor of 2 is one stop.

http://www.kodak.com/US/plugins/acrobat/en/motion/support/h2/h2fltrs.pdf

That's the only Kodak document I could find. Filter factor of 3 for a #15. So more then one stop.

 

[RobertP]

Yes a filter factor of 3 would be 1 2/3 stops as the tech at Tiffen said. But why when metering through the filter does it indicate only a 2/3 of a stop difference?

 

[Nick Zentena]

Meters don't always see light how film does. Filter factors try to take into account how film sees. Neither is perfect.