I recently purchased a Cokin filter system for B+W 4X5 photography. I got the 0 01 yellow, 002 orange, 003 red, 004 green and 160 polarizing filters. Simple en ough. However, things seem to always be more complicated. No literature came w ith them. Therefore no info was provided on how to contact Cokin with questions . I don't even know what country they are located in. I tried and e-mail searc h and the 1-800 operator, but to no avail. Does anyone know how to get ahold of Cokin or would any of you like to try to address my questions ?
1. Cokin provided no filter factor for the polarizer. I put it on my spot meter and found a 2 f stop decrease. This matches some literature, but others say a bit more. OK on this one I guess other than Cokin gave no indication of what it should be.
2. The yellow filter factor provided on its plastic container is 13 f stop. I cannot find any standard yellow filter that matches this. I put it on my spot me ter and found it reduced exposure by 2/3 f stop which is standard for a number 6 yellow filter . Anybody know whats going on here ?
3. Cokin indicates on the orange filter container that the f stop adjustment is 1. This does not match any in the literature I have. I put it on my spot mete r and found nearly a 2 1/3 f stop difference which matches a number 21 orange. Any ideas ?
4. OK on the green and red. Cokins f stop recommendations match my meter and t he literature.
5. While trying to figure all of this out, I noticed that the recommended filte r factor adjustments are different for some filters for Tri-x and T- max. I'm t otally confused now.