Filter stop differences

[Santo Roman]

I have a few Cokin A series filters for my 4x5:

Cokin A. 004 Green
Cokin A. 001 Yellow
Cokin A. 003 Red

I just wanted to know if anyone had a good idea on what f/stop differences were for each filter or if there was a site that could tell me.

thanks,

santo

[Steve Barber]

Strange, aren't they marked on the filter?

http://www.geocities.com/cokinfilter.../exposure_.htm

[ki6mf]

if you have a spot meter shoot through the filter when taking measurements and don't worry about the filter factor. The published factor, what ever that may be, can also be different from the real factor.

[kev curry]

Strange, aren't they marked on the filter?

http://www.geocities.com/cokinfilter.../exposure_.htm

Steve, all you get on the Cokin contrast filters is the 3 digit number.

if you have a spot meter shoot through the filter when taking measurements and don't worry about the filter factor. The published factor, what ever that may be, can also be different from the real factor.

Wally, dont you add exposure compensation after metering through the filter?

After metering through a Cokin 003/Red filter for example, you need to add an additional 2 stops of exposure.

[Daniel_Buck]

I've always just metered through the filter, haven't had any problems

[Santo Roman]

Strange, aren't they marked on the filter?

http://www.geocities.com/cokinfilter.../exposure_.htm

I was looking at the chart Steve but was not sure if it was Cokin's numbers were correct or not.

santo

[Santo Roman]

Steve, all you get on the Cokin contrast filters is the 3 digit number.



Wally, dont you add exposure compensation after metering through the filter?

After metering through a Cokin 003/Red filter for example, you need to add an additional 2 stops of exposure.

For what Wally was saying on how to meter through the filter and use that reading is what I have done in the past with no problem, but wanted to know if I have been doing it for years. I've used the opaque filter for Infrared in the past and always had to adjust for that but with other color filters I figured that I'd get a few other suggestions.

Thanks for the help.

santo

[photographs42]

Using a spot meter and metering through the filter has always been of great benefit because color filters are usually used to provide more tonal separation between objects of similar luminosity but different color. Metering through the filter allows you to measure the difference and at the same time adjusts for any filter factor.
Jerome