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  1. #21
    Lee L's Avatar
    Join Date
    Nov 2004
    Multi Format
    Quote Originally Posted by darinwc
    I wouldnt think that any reflective surface would provide enough difference to cover more than 2 or 3 zones.
    The standard gray scale patches on a MacBeth Color Checker cover reflection densities from 0.05 to 1.50, which is 4.8+ stops. I'm not quite sure what you mean by zones in this context, but if you mean stops, you can certainly get a broader range than 2 or 3 stops with common materials all in the same incident light.


  2. #22

    Join Date
    Jun 2004
    Portland, OR
    4x5 Format
    I visited Alan Ross last year, and he had a large black box mounted on his window, so I asked what it was. He opened it up and it had a 3x3 (I think, maybe 3x4) grid of Wratten ND filters mounted against the window. Each grid was a one stop difference. The other side of the box had an opening to place the camera lens into so it can shoot the grid. He had an additional side opening so he could meter off the grid before making an exposure.

    He commented on how expensive it would be to make one of these today due to the cost of Wratten filters, but I think it could be done quite a bit cheaper with Lee or Rosco theatrical filters. The grids were something like 3 or 4 inches square, and you could buy a sheet each of 1, 2, and 3 stop ND theatrical filters and just cut them up and sandwich the filters. Total cost for the filters should be about $25.

    If you do this, make sure you set the focus for the lens at infinity. The grid will be out of focus, but the samples he showed me were not too blurred that you couldn't make good densitometer readings.

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