Baader Filters 2 ‘ Semi APO Filter (flat-optically Polished) – 04/07

The Fringekiller blocks about a third of the blue light. The transmission in red and green light is 100%. The resulting loss of light over the entire spectrum is only about 12%.

The semi-apo filter blocks more than 25% in blue and red light. The proportion is lower in green, but about 30% of light is lost across the entire spectrum. But the colours are once again neutral, except for a slight green tint. The light reducing effect of the semi-apo filter is about half a stop.

(Bernd Gährken)