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Why is aperture backwards?


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4 replies to this topic

#1
robertcarter687

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So, I get that larger f numbers like f/22 actually mean that it's a smaller opening and that smaller f number like f/2 is a big opening. I learned that thanks to a really helpful beginner video I just watched - https://www.youtube....h?v=fpdxMUWF0k0. But my question is this...WHY is the size of the aperture backwards from the numbers. Shouldn't f/22 be a big aperture since it's a big number and f/2 should be a small aperture since it's a small number???


#2
Jerry_

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This is because the Aperture is a RATIO and

1/2 (=0,5) > 1/4 (=0,25) > 1/8 (=0,125) ...

To find out more about why the f-number is a ratio and what it describes you can read the extensive article on Wikipedia
f-number - Wikipedia

#3
Nikon Shooter

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This because the Aperture is a RATIO…


… and that ratio reflects the inverse square law proportions.



#4
TBonz

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Do not think of it as the smaller the diameter, the larger the #.  Instead, think of it the opposite way...the larger the number, the larger the depth of field...

Other than that, see the answer above



#5
Nikon Shooter

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1/2, 1/4, 1/8, 1/16, 1/22…
The numbers get bigger but the fractions smaller!