optolong filter
This filter is designed to enhance the contrast of deep-sky objects and soften the brightness of the background sky, thanks to a sophisticated transmission that lets through light from the lines on which deep-sky objects shine (H-alpha, O -III , N-II, H-Beta, S-II…), but blocks harmful light emissions (for example the Hg line, or wavelengths of sodium vapor illumination). It also reduces background glow caused by oxygen in the atmosphere ("skyglow"). This filter is recommended for use in areas with light pollution and is suitable for both visual and photographic use.
Compared to other filters to reduce the effects of light pollution, such as UHC or CLS filters, this is a multi-bandpass filter that only minimally affects color rendering. Therefore, it is suitable for photographing objects that emit continuous light: not only emission nebulae, but also galaxies, star clusters, reflection nebulae, etc. You can achieve exposures up to 3 times longer than unfiltered exposures.
Treatment characteristics:
The treatments are not cemented onto the optical support, but are spread by electron beam evaporation and subsequent ion beam assisted deposition (IBAD process). This special process allows for extreme durability and scratch resistance, ensures central wavelength (CWL) stability, and prevents thermal drift. In addition, it allows a high transmission in the pass band and a high optical density in the range of blocked frequencies.
Attention, this filter must never be used only to observe the Sun!
with frame for mounting on Canon EOS cameras with full frame sensor
Attention: The filter can be used with EOS 6D, EOS 5D, EOS 5D II and EOS 5D III! The new models (EOS 6D II, EOS 5D IV) do not allow the use of this filter! The filter prevents the usual movement of the rotating mirror when capturing images. With the EOS 6D II and EOS 5D IV, this causes a malfunction in camera operation.
Attention, this filter must never be used only to observe the Sun!
This item is not available to customers in Germany.
Specifications: