Clear Sky--Screw-on Filter

[Screw-on filter]

Optolong Clear Sky is 2017 first new launched by OPTOLONG professional astro filter manufacturer. Clear sky filtered Na and Hg light pollution improved the contrast.

Screw-on filter is front of length have no vignetting that can be screw-on the lens such as UV filter. And it can’t cause wavelength shift. All of lens that with UV, so does Screw-on filter. Clear sky is very conveniently because it can be screw on lens directly. What’s more, it save time.Clear sky can be used in 77mm and 82mm lens. 

 Contrast image from HK famous photographer Vicent Cheng with Clear sky.

 Chinese famous wild filed photographer Royalk who had been published in <夜空中国> to evaluate Clear Sky first time.

Clear sky manufactured by auto coating process

  

                                            

Brand	OPTOLONG
Name	Clear Sky
material	Optic glass
Thickness	1.0mm
Size	77mm（Only）
Frame	CNC machining