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  1. #1

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    Another question about filters

    Hi everyone

    I went on evilBay to buy a Bay 1 yellow filter for my new Rolleicord. I always use K2 yellow as a regular B&W filter. The listing I bought had a pic of a medium yellow (K2 filter) but the description actually said it was a light yellow (K1) filter. Well, I didn't read that bit (note to self: read BEFORE you buy).

    So my question is: will I see more or less the same effect with the light yellow as with the medium yellow I always use? I know the filter has little effect in cloudy conditions, but what about in sunlight, such as dawn/dusk conditions?

    Thanks in advance

    Alex

  2. #2
    Rick A's Avatar
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    Yes, to some extent, but not quite as pronounced. What is the filter factor for it,one or two with a K1, 1/2 stop or one stop correction?
    Rick A
    Argentum aevum
    BTW: the big kid in my avatar is my hero, my son, who proudly serves us in the Navy. "SALUTE"

  3. #3

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    The Rollei manual says the light yellow has a filter factor of 1.5, while the medium yellow has a filter factor of 2.

  4. #4

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    Close, but no ciger!

    Jeff

  5. #5

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    Quote Originally Posted by Jeff Kubach View Post
    Close, but no ciger!

    Jeff
    What do you mean? Similar effect but not quite?

  6. #6
    Bruce Osgood's Avatar
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    Keep in mind, you do not want to confuse Factors with Stops.

    My understanding is the Square Root of a Factor is the Stop. In the case of a Factor of two you would open the lens 1.4 Stops and a Factor of 1.5 would be 1.2 Stops.

  7. #7

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    Really I don't somke cigers! There is a small difference.

    Jeff

  8. #8

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    Factor = 2^Δf

    Δf = ln(factor)/ln2


    Example:

    #8 yellow = K2 is a 1-stop filter with factor 2

    Factor = 2^1 = 2

    Δf = ln(2)/ln2 = 1 stop


    For the light yellow K1 (#6)

    Δf = ln(1.5)/ln2 = .58 stop (usually rounded up to 2/3 stop)

  9. #9
    Rick A's Avatar
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    Roughly between 1/2 and 2/3 stop. So, if your lens has two marks between stops, you use the second one. If there is only one mark between stops, use that.
    Rick A
    Argentum aevum
    BTW: the big kid in my avatar is my hero, my son, who proudly serves us in the Navy. "SALUTE"



 

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