Links

f i l t e r f i n d . n e t

http://www.heliopan.de/Heliopan-Filters.pdf

http://www.thkphoto.com/products/hoya/index.html

http://www.cokin.fr/ico1-p1.html

http://www.schneiderkreuznach.com/pdf/filter/bw_filter_programm_e.pdf

An overview of filters essential for Digital Photography

http://www.photo.net/equipment/filters/digital

shooting with Infrared:

http://infrareddreams.com/harrison.htm

http://www.tiffen.com/userimages/Tiffen_Bfilt_Broch_07_std.pdf