【SUMMIT SERIES】★L -Pro Filter★
L-Pro is multi-bandpass filter which offers better color balance by maximizing the transmission band. The balanced transmission allows astrophotos to be taken with minimal color cast to broadband emission objects such as galaxies, reflection nebulae and globular star clusters. L-Pro is the best choice for light pollution suppression.
  • Description

  • Specification

1. L-Pro Introduction and Function

The L-Pro (L-Professional) filter is designed to improve the visibility of various deepsky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lightings including mercury vapor lamps, both high & low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). Together with the highly transparent in main nebula emission lines at OIII(496nm and 500nm), H-beta (486nm), NII(654nm and 658nm), H-alpha(656nm) as well as SII(672nm), the filter is suitable for enhancing the contrast and details for both visual and photograghic purpose at sub-rural area with heavy light pollution.

Optolong L-Pro is multi-bandpass filter which offers better color balance by maximizing the transmission band. The balanced transmission allows astrophotos to be taken with minimal color cast to broadband emission objects such as galaxies, reflection nebulae and globular star clusters. L-Pro is the best choice for light pollution suppression.

Main Use and Performance

Suitable for visual observation and astrophotography.

L-Pro filter has a very low transmission reduction rate against continuous spectrum space objects, and thus is quite effective in suppressing light pollution sources when shooting galaxies, reflection nebulae and globular star clusters. The same holds true for visual star observations.

L-Pro filter alone can suppress infrared wavelength, and thus can be used at ease for “L” image shootings with CCDs.

Light pollution filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.

WARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.


2. Transmission Curve of Optolong L-Pro Filter

How to read the chart?

▲The horizontal axis is the Wavelength in Nanometers(nm).

▲The vertical axis is transmission in %.

▲The RED line shows the transmission of the filter. The artifical emission lines are shown in ORANGE. And the emission lines from constellation are shown in GREEN.


3. L-Pro features

Specifications Applicable camera model Applicable lens Unit Price in US$
1.25" M28.5*0.5 / $149
2" M48*0.6 / $199
77mm M77*0.5 / $289
EOS-C clip 7D2/80D/800D/77D/70D/760D/750D/700D 650D/600D/550D/500D/400D/100D/1100D 1200D/1300D

All EF lenses. But not suit for Canon EF-S lenses.

EOS-FF clip 5D, 5D MarkII, 5D Mark III, and 6D. All EF lenses $269
NK-FF clip D600/610, D700/750, D800/800E,D810/810A,DF All lenses that made from Nikon, when released after 2003. $269
Sony-FF clip A7M/A7M2/A7M3/A7R/A7R2/A7R3/A7S/A7S2/A9 All E-mount lenses $269


For camera clips, we only test the popular lens in market. For any other lens , feel free to contact our customer service staff. We would like to extend our sincere thanks for your support and test data.


4. Manufacturing Technology

  • High-precision grinding and polishing to make sure the substrate parallelism is greater than 30" and the surface accuracy is better than λ/4 ;
  • Purified water ultrosonic clearning is aim to effectively remove impurities and dust from the substrate surface.
  • Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change; IAD not only consolidates membrane compactness, increases film firmness, but also changes vacuum coating material characteristics.
  • Planetary rotation system offers precision and homegeneity of coating ensuring high value on transmission of pass-band and Optical density of off-band;
  • Non-cementing optical substrate coating;
  • Quality Control: each filters is examined by Spectrophotometer for spectrum characteristic, and Laser Interferometer for surface accuracy.




5. Package 


2019 NEW package

Note:We are now in the transition from the old to the new packaging style, ship is random.


6. Optolong L-Pro Performance

I Comparason image was shot by Arnaud Besancon

All the pictures have been realised with 5D3 Astrodon modded and Samyang 24mm F1,4 at F2, 13s exp. time,3600 isos.

All the pictures are raw,without post-process



II The Vortex galaxy by Luca Fornaciari Astrophotography

Optolong Astronomy Filter L-Pro 2''



III Ran into Red Sprite again©Vincent Cheng

The Red Sprite is a TLEs (Transient Luminous Events) from the atmosphere, and is part of a family of small creatures that also include even harder to photograph, from rogue sprites to blue jets.

by Optolong_filter  2" L-Pro filter



Ⅳ When the skies were absolutely STEADY, Jim Mayercak shot this Luna

cannot recall EVER having such good "seeing" conditions. The most beautiful Lunar shot to date.Celestron CGEM DX 1100 EDGE HD ZWO ASI071PRO

Optolong L-Pro filter



V Here the final Image of comet 46/P Wirtanen and the Pleiades, shot by Blake Estes.

This imaging run ended up being a marathon that took about 22 hours of processing, using Optolong L-Pro filter for imaging. Its absolutely perfect!



Ⅵ  Veil Nebula shot by Andrea Andreotto Maggi with Optolong L-Pro filter 2''

The L-Pro filter filter allowed me to obtain long poses without saturating the stars and to obtain a good separation between the nebula and the sky background while keeping the colors unaltered.



VII Summer Milky Way-Cameron Highlands, by Sammax Chong with Optolong L-Pro filter

Light Pollution Levels - 5,Date - 2019-3-10,Time - 3.40am, Location - Cameron Highlands
Camera - Nikon D750(mod),Lens - Sigma Art 20mm F1.4; Tracking Mount - Vixen Polarie,Optolong L-Pro filter
Exposure Time- Sky 4 X 180s Panorama Stitching,Foreground 4 x 180s Panorama Stitching,ISO - 800; Aperture - f3.5,Process - Autopano Giga,PSLR PSCC



VIII. Horsehead nebula IC434, shot by Wuzhen. 
I believe you have to understand somewhat, but took a whole winter total of 80h exposure of the horsehead nebula is rare, especially the dark clouds details around it is more spectacular.
Camera: QHY128C
Telescope: Celestron RASA 11"
Filter: Optolong L-Pro
Data: exposure for each 10min,80 hours in total
Copyright: Wuzhen
Processing: DR.Liao



Warm prompt

●About color: due to the influence of ambient light, color difference of the display and flash photography, the color of the product may have some color difference. Detailed color is in accordana with the final product.

●About coating: the interference filter will show different colors under different light, which is a normal phenomenon. Please refer to the material object.

●About the style: in order to improve the product, the change of design/appearance/parameters has not been updated in time. Please see the subject produce.

●About the description: the series of this product have the same material, technology and design, different sizes only, please note.

Optolong L-Pro features 4 sizes:

★1.25"(1 1/4" mounted), 2" mounted for eyepiece

★Round 77mm mounted to screw on the objective lens of telescopes.

★SLR Camera clip filters