Astronomik has a long history of top quality filters, and the L2 is just another testament to that reputation's truth. Working as a perfect UV-IR blocking filter, it lets the full range of sensitivity of the human eye (according to DIN 5031) pass, and blocks all other parts of the spectrum in the UV and IR. This makes it an ideal choice as a luminance filter for any kind of digital photography. It is optimized for systems with focal ratios between f/0.5 and f/50, and the typical transmission is higher than 99%. The UV-IR Blocker gives you a perfect parfocal filter for the luminance channel. It is also great as a dust protection for your telescope and camera. The high quality L2 has an very narrow spectral window- see the graph above for exact transmission rates.
If you use an optical system that is completely free of any chromatic aberration you should get an L1 filter for your setup. For general use the L2 filter is well suited to most optical systems with a corrector, flattener or reducer in the optical train while the L3 filter is designed for users of refractors with a less-than-perfect color correction.
Manufacturer Product Number: L2-T