Optolong L-PRO Maximum Luminosity Filter - SONY FULL FRAME Clip Filter

Optolong L-Pro (L-Professional) filter

The SONY FULL FRAME version is the latest clip filter 

The Optolong L-Pro (L-Professional) filter is designed to provide maximum luminosity of the spectrum other than those areas caused by light pollution...Designed for slightly light polluted, suburban and rural areas where there is light pollution, but not severe.

It improves 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). As this filter is 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.
Unlike other light pollution filter UHC and CLS, 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.

By providing maximum luminosity it reduces exposure time that is an important factor in deep sky imaging.

Compatible with the following FULL FRAME SONY cameras (please note, we cannot take responsibility if the camera manufacturer changes some dimensions and some models become incompatible or if there is variation in compatibility between same models):

A7M / A7M2 / A7M3

A7R / A7R2 / A7R3

A7S / A7S2

A9

WATCH ON YOUTUBE!

(Please note, we've tried to install it on our Sony a7III and it wasn't as easy as shown on the video, but we did it. I think these new cameras have a slightly different internal shape. The space is there, but imagine a trapesoid shap of the chamber and the same trapesoid shape of the filter housing... you cannot slide it in from the side (like you would do it with a finderscope shoe and finderscope base), but you have to slide it down from above and as the bottom of the filter housing is a tiny bit wider than the top of the opening, it is tricky. I inserted the left had side and then slightly pulled the middle back with my fingers whilst pushing down the right hand side, thus slightly bending the whole housing... remember, there is a thin glass in there that I was bending... well, yes, it's tricky, but doable. Remember, this relates only to the a7 Mark III camera!!! ... and note that if you break the glass during this process, we won't be able to take responsibility. Yes, there are some risks in life...)

APPLICABLE LENSES: this filter has been tested with popular E-mount SONY lenses, therefore we cannot guarantee that it will be compatible with all available lenses. Plese install the lens carefully once the filter is in place. In case of any doubt, please contact us and we'll ask the manufacturer to verify if they tested the filter with a certain lens. We won't be able to take responsiblity if you break the glass of the filter or damage your lens or camera.

Images are for demonstration only. Camera is not included. Similar product might be shown on some images.

Main Use and Performance

Suitable for visual observation and astrophotography. The optolong 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. The L-Pro filter alone can suppress infrared wavelength, and thus can be used at ease for “L” (luminosity) image shootings with CCD cameras. Please note that light pollution filters do not completely eliminate the effects of light pollution and definitely do not increase the object’s brightness, however they increase the contrast between nebula and night sky by making the background darker.

WARNING:

Optolong filters are not designed for solar observation. DO NOT LOOK AT THE SUN WITH ANY OPTOLONG FILTER as permanent eye damage will be the result.

Technical Data

• Schott substrate material
• Glass thickness 2.0 mm (1.25”/2”/77mm)  and 1.0 mm (Clip series)
• Surface Quality: 60/40 (Refer to MIL-O-13830)
• Fine-optically polished to ensure accurate 1/4 wavefront and < 30 seconds parallelism over both surfaces
• 90% transmission of main nebula emission lines (i.e. Ha 656nm, OIII 496nm & 500nm, SII 672nm and H-beta 486nm).
• Pricision transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm).

Filter Cell

• Ultra-thin filter cell minimise vignetting by maximising possible clear aperture (clear aperture is 26mm for 1.25” size and 45mm for 2” size)
• Aerometal Material
• Precise CNC Machining
• Sand Blasting Process
• Black Anodized Finish
• Extinction Treatment to Prevent Reflection
• Laser Engraving No Fading

Available Sizes

• Standard 1.25” & 2”
• Round 77mm Unmounted
• Clip Filter Series (RESTRICTED TO GERMANY! Please do not order Optolong Clip filters from Germany. We can sell only Astronomik EOS Clip filters to Germany.)

Compatibility

This filter is compatible with the following FULL FRAME SONY cameras: A7M / A7M2 / A7M3 / A7R / A7R2 / A7R3 / A7S / A7S2 / A9

Packaging

• Plastic PP Case
• Imported High Pressure EVA Case Lining
• Silver Cardboard Box
• High Density Sponge Carton Lining

Optical Coating

• Multi-layer anti-reflection coating
• Non-cementing optical substrate coating
• 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.
• Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band. (Please note, "planetary rotation system" is a type of optical coating process and does not refer to the astronomical system describing the motion of the planets in our solar system.)

The Major Emission Lines of Nebulae: H-α 656.3nm, H-β486.1nm, OIII 495.9nm, OIII 500.7nm 
The Major Emission Lines of Artificial Light Pollution: Hg 435.8nm, 546.1nm, 577nm, 578.1nm, Na 598nm, 589.6nm, 615.4nm, 616.1nm