Filter question

[131802]

I recently acquired a filter with some other gear, and I'm not sure what it does. It's labeled "ZENTZ R/B 52 mm JAPAN". Like a polarizer, it has two pieces of glass, both in the red to purple range. The rear element is fixed; the front turns freely. Looking through the filter at a white wall, the color shifts from redish to blueish as the front element is turned. Any idea what this filter does?

 

[jim10219]

Sounds like a red/blue varicolor polarizing filter. They're probably more useful for B&W film, but may be interesting for weird effects with color film.

 

[RalphLambrecht]

I recently acquired a filter with some other gear, and I'm not sure what it does. It's labeled "ZENTZ R/B 52 mm JAPAN". Like a polarizer, it has two pieces of glass, both in the red to purple range. The rear element is fixed; the front turns freely. Looking through the filter at a white wall, the color shifts from redish to blueish as the front element is turned. Any idea what this filter does?

I think it shifts the color from redish to blueish as the front element is turned

 

[AgX]

Sounds like a red/blue varicolor polarizing filter. They're probably more useful for B&W film, but may be interesting for weird effects with color film.

Exactly.

It is the combination of a filter "similar" to an effect colour filter (bandpass) and a linear polarizer. Intended for colour photography.

In Germany B+W offered three of such filters (magenta, blue, green). However without polarizer, for which one had to use ones own linear polarizer. By this the effect filters are more economic, and even can be used on their own with their default hues.


Funny, just today I wanted to start a thread on these Magicpol filters. As nowhere I could find any hint at the way they function...
With the polarisation in mind one could think it is a matter of colour saturation. But at least with the magenta one it is obviously a change of hue.

So, if someone knows...