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Very interesting approach to variable ND
  • FUJINON ND-P01 Optical Variable ND Filter




    Text is quite bumpy, but main idea is that bu turning two gradient wheels in opposite direction you can get even ND from 90% transparancy up to 1/64 original light only.

    And no cross and color shift issues associated with reverse poliriser filters. :-)

    468 x 446 - 17K
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  • 6 Replies sorted by
  • Very interesting idea indeed, however I'm having a bit of trouble believing the gradients on both wheels add up uniformly. I don't doubt my geometry can be seriously flawed, but my intuition tells me there is going to be some "vignetting". :(

  • intuition tells me there is going to be some "vignetting". :(

    What kind of vignetting?

  • Ah, forget it. I wasn't thinking straight. The 3D representation fooled me because I wasn't imagining the stacking of the gradients correctly with their centers on the same axis (light path axis).

    The yellow arrow is on the right spot, you can only use the top half of the filters because the way they are represented (perfectly aligned) they will be uniform on all the filter (top & bottom) but as soon as they start rotating in the black arrow direction it will become darker on top (yellow arrow zone) but it will become lighter on the bottom and the discrete transition from black to white would immediately show a pattern.

    It makes perfect sense now. It's a great invention, the only drawback I see is that the diameter of the filter has to be at least twice the size of a similar VND. Well worth the advantages (light transmission up to 90%).

  • The other very important advantage is avoiding polarizers, as Vitaliy wrote. Apart from the cross or color shifts, they can have nasty effects on windshields or similar tempered glass. Plus, sometimes you just want to keep those reflections which are usually suppressed by them.

    Very interesting indeed!

  • @nomad Thanks for the extra input.

    I didn't knew about those other issues, I rarely have gone into trouble even with cheaps VND (perhaps because I rarely use them). The cross effect only shows when I'm using it at the maximum. Now, 25% light transmission against 90% that's decisive. :)

  • i dont understand why it needs external power... would be cool if they would have the same system as a mount for MFT/M43