Optolong Clear Focusing Filter 2"

Optolong Clear Focusing Filter 2"

The Optolong Clear focusing filter is designed to pass through the visible spectral region between 420nm and 680nm at a high transmission level of 98.5%.

Clear Focusing Filter Introduction

Main Use

Use of astrophotography filters, especially narrowband filters, often result in dim images which can be difficult to focus. Clear focusing filter can be used first to clearly focus the image as it lets through practically all the light in the visible spectrum.

Use with modified DSLRs for higher efficiency and sensitivity by passing visible range with 98.5% transmission.

Act as an outstanding dust shield, which prevents the possibility of dust settling on the lens during long time exposure.

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.

Clear Focusing Filter Spectrum and Characteristic

Substrate: B270
Thickness: 1.85mm
Tave:  T>98.5%
Surface quality: 60/40
Transmitted Wavefront RMS: λ/4
 Parallelism: 30s

Notes

●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 accordance 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 specification.

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