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Thread: Close-up Filters, when? How?

  1. #1

    Default Close-up Filters, when? How?

    How does Close-up filters work? And when is it applied? I can't seem to find any technical information on the application of Close-up filters. Thanks!

  2. #2

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    Quote Originally Posted by bernards
    How does Close-up filters work? And when is it applied? I can't seem to find any technical information on the application of Close-up filters. Thanks!
    work exactly like a magnifying glass ..
    See my Photo Gallery at the Clubsnap

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    Quote Originally Posted by bernards
    How does Close-up filters work? And when is it applied? I can't seem to find any technical information on the application of Close-up filters. Thanks!
    Close filters are used in macro photgraphy.. when you want to make small things look big.... They come in different strengths eg 5T, 6T for different degree of magnification.

  4. #4

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    Close-up filters comes in a variety of diopter ratings (e.g., +1, +2, +3, +4, +10). These ratings refer to the magnification power. Close-up filters are meant to reduce the minimum focusing distance of your existing lens. By being able to focus at a shorter distance, the object will look bigger. The higher the diopter rating, the shorter the minimum focusing distance, and hence the bigger the magnification.

  5. #5

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    Thanks for the clarification guys.

    On the technical side. If I have a minimum 10 cm distance for macro. How many cm did I just reduce by using a +4 close up filter?

    I just bought a set of Hoya filters that come in +1, +3 and +4. Can I stack them one infront of another to get closer?

  6. #6

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    Here's the calculation... the optimal focusing distance for the closeup lens/filter is
    1000mm / x (Where x is the sum of all the numbers added together)

    Eg. If you have just a +4 filter..
    1000mm / 4 = 250mm = 25cm distance (Same as Canon 250D)

    Or you can stack a +4 & +2
    1000mm / (4+2) = 166.66 mm = 16.6cm

    If you need to get to 10cm, then you need the +10
    1000mm / 10 = 100mm = 10cm

  7. #7

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    Thanks all. It's all clear like a sunny day now!

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    may I ask from where this “1000mm” comes from? I understand the calculation but could not relate this 1000mm to a physical property.

    Also I have the Canon 250D and the Hoya +4, given both have the same magnifying power, how come the Canon is like three times as heavy as the Hoya? Not to mention the price!!

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    is it right? well it is thicker and heavier. will go home and examine it. in any case for prosumer cam the lens barrel is so small it uses the centre portion only.

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