Heliopan 52mm Medium Red #25 Filter
Light red is the ideal filter for strong contrast improvement since it absorbs green and blue completely and enhances red. Clouds are dramatically improved almost to the mood of a thunderstorm. It is more effective in cutting through haze, and moon light effects are easily accomplished. It is also suited for infrared photography. The filter factor is approximately 8x. When using TTL metering set the exposure correction to +1 (except when using Technical Pan Film).