{"id":28821,"date":"2025-09-19T11:55:15","date_gmt":"2025-09-19T09:55:15","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&p=28821"},"modified":"2026-07-20T14:51:01","modified_gmt":"2026-07-20T12:51:01","slug":"optolong-filters-l-quad-enhance-2","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/optolong-filters-l-quad-enhance-2\/","title":{"rendered":"Optolong L-Quad Enhance 2''"},"content":{"rendered":"

Optolong L-Quad Enhance 2'': four bands, one filter, more contrast<\/strong><\/h2>\n\n\n\n

The L-Quad Enhance Filter (L-QEF) is Optolong's quad-band light pollution filter for color cameras. Four passbands around the H-beta, OIII, H-alpha, and SII emission lines allow nebulae signals to pass through with over 90 percent transmission, while suppressing mercury and sodium lamp emission lines with an OD2 to OD4 blocking depth.<\/p>\n\n\n\n

Unlike narrow dual-band filters, the L-QEF maintains a good color balance across the entire spectrum, making it versatile for everything from emission nebulae to galaxies, star clusters, and widefield shots of the Milky Way.<\/p>\n\n\n\n

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The middle ground between L-Pro and dual-band<\/h4>\n\n\n\n

The L-QEF sits between a broadband and a dual-band filter in character: more contrast on nebulae than an L-Pro, while maintaining color balance and usability on broad-spectrum objects. Optolong recommends the filter for skies up to Bortle 7.<\/p>\n<\/div>\n<\/div>\n\n\n\n

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Thoughtful technique<\/h4>\n\n\n\n

A near-infrared block up to 1000 nm prevents inflated stars, and the multi-layer ion-assisted coating is scratch-resistant and temperature-stable. The slim 2-inch barrel with M48 thread fits into filter holders, filter wheels, and photo adapters.<\/p>\n<\/div>\n<\/div>\n\n\n\n

Featured accessories<\/h3>\n\n\n\n

For pure emission nebula work under heavy light pollution, the dual-band filters L-eXtreme and L-Ultimate are the next step.<\/p>\n\n\n\n

For whom yes and for whom no<\/h3>\n\n\n\n