Optolong L-Quad Enhance (L-QEF) is a quad-bandpass light-pollution suppression filter for one-shot colour cameras. It improves contrast while keeping natural broadband colour, so wide-field scenes and deep-sky targets look balanced instead of heavily tinted. It’s designed to cut common artificial light sources and background glow so you can capture more signal in less time from suburban sites.
Quad-band design that maximizes colour balance for broadband targets while improving resistance to light pollution.
>90% transmission at the main nebula lines (H-β/OIII/H-α/SII) with OD2–OD4 out-of-band blocking for strong contrast.
Near-IR cut to 1000 nm to reduce sensor IR noise and star bloat.
Multi-layer anti-reflection coatings using ion-assisted deposition for durability and stable central wavelength.
Optical quality: 1.85 mm substrate, surface quality 60/40, transmitted wavefront RMS λ/4, parallelism 30″.
Where it shines: Milky Way/wide-field, galaxies, clusters and many nebulae; recommended roughly for Bortle 1–7 skies.
Format: 2″ mounted (M48×0.75).