Optolong L-eXtreme

Formats

  • 1.25″ Mounted
  • 2″ Mounted (48mm thread)

Spectral Transmission

Yellow line is published transmission. Color fill is my independent verification with the filter I tested.

Physical Characteristics of 2″ Filter

  • Filter mount thickness: above threads: 4.92mm; including threads: 6.78mm
  • 48mm threads with 0.75mm spacing
  • Minimal knurling only on top
  • Dual bandpass narrowband filter
  • Inner retaining ring does have notches for easy filter disassembly with a spanner
  • Width of the glass filter without the filter mount is 45.94mm

Real World Tests

Bortle 8, Stock Canon T7, 464mm f.l., f/5.4, ISO3200, 36 min. integration (6*6″). Open full-size image in new tab.
Bortle 8, Full Spectrum Modified Canon 60D, 464mm f.l., f/5.4, ISO3200, 36 min. integration (6*6″). Open full-size image in new tab.

Comparisons to No Filter

Before Image After Image
Stock Canon T7 - No filter vs. Optolong L-eXtreme

Before Image After Image
Full Spectrum Canon 60D - No filter vs. Optolong L-eXtreme

Reader Rating46 Votes
77
Pros
7nm bandpasses provide good contrast and tight stars
Excellent light pollution blocker
Cons
Faint halos on very bright stars created by filter
Not available in clip-in format
90
Purchase from:
  1. Hi i wnat to know if there is best filter under 250$. I live at sky bortle 8 or 9. The first product I’m considering is l extreme and i want is there any better narrowband filter

    1. Hello, I would suggest getting a dual-narrowband filter that is in your price range. These are ideal for blocking light pollution like you have with Bortle 8/9. Lately, I have found the Svbony SV220 is a very good value and similar (if not slightly) better performance than the L-eXtreme. They both have dual 7nm bandpasses on Ha and OIII. Keep in mind these types of filters are only appropriate for emission nebulae. It will be counter-productive to use them on reflection nebulae, star clusters, and other broadband objects.

Your email address will not be published. Required fields are marked *

Final Score