FLW filter - PentaxForums. com PentaxForums com → Photography → Photographic Technique → FLW filter « Cross-polarization is cheap and fun - a short brain dump with sample photos | Filter for next years solar eclipse »
Purpose of 81A Filters ? - PentaxForums. com I have just received a used Hoya filter from Ebay, not an 81A, but the keeper case has a chart of filter factors on the back Under 81A it says it