Close-up Filters, when? How?


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bernards

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Feb 17, 2004
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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!
 

megaweb

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#2
bernards said:
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 ..
 

justarius

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#3
bernards said:
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.... :D They come in different strengths eg 5T, 6T for different degree of magnification.
 

azone

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#4
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.
 

bernards

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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?
 

willyfoo

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#6
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
 

bernards

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

hwchoy

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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!! :(
 

hwchoy

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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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