The Optolong L-eXtreme is a dual 7nm bandpass filter that can be used with single shot color cameras such as DSLRs (digital single lens reflex cameras) and monochrome CCD cameras. It is also suitable for "fast" optical systems. The nature of this filter allows emission nebulae to be photographed even in skies with heavy light pollution. Optplong believes the L-eXtreme filter design would be a better option for fast systems at competitive prices. The Optolong L-eXtreme filter isolates the emission lines of the H-Alpha and OIII nebulae, maximizing the contrast and the signal-to-noise ratio between nebulae. For people who live in areas with a lot of light pollution or who want to take photos when the moon is out, the L-eXtreme is a great filter.
Unlike the L-eNhance filter, which is a three-band filter (transmits Hb, Ha, and OIII), the L-eXtreme filter is a dual-band filter that allows the H-Alpha and OIII emission lines to pass.