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Thread: Diameter/Circumference of Lens

  1. #1

    Default Diameter/Circumference of Lens

    We know that the f-stop of a lens controls how large the aperture opens to let light gets into the sensor, but I am curious if the diameter (or is it circumference) of the lens makes a difference?

    Sounds like a stupid question, but I am really curious.

  2. #2
    Member agws1970's Avatar
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    Default Re: Diameter/Circumference of Lens

    Quote Originally Posted by AMediaLuz View Post
    We know that the f-stop of a lens controls how large the aperture opens to let light gets into the sensor, but I am curious if the diameter (or is it circumference) of the lens makes a difference?

    Sounds like a stupid question, but I am really curious.
    First Google hit for Focal Length F Stop

    http://www.paragon-press.com/lens/lenchart.htm

    Really learn to google okay? Hehe.

  3. #3

    Default Re: Diameter/Circumference of Lens

    Quote Originally Posted by AMediaLuz View Post
    We know that the f-stop of a lens controls how large the aperture opens to let light gets into the sensor, but I am curious if the diameter (or is it circumference) of the lens makes a difference?

    Sounds like a stupid question, but I am really curious.
    Short Answer: NO.

  4. #4
    Senior Member giantcanopy's Avatar
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    Default Re: Diameter/Circumference of Lens

    The f number is derived from a ratio of focal length to effective aperture diameter.

    Indirectly, since a faster f stop needs a larger effective aperture diameter for a given focal length, u will physically need a larger lens construct.

    No hard and fast rule. There are many other factors such as lens design etc ..
    But if you have a 50mm f1.8, 50mm f1.4, and a 50mmf1.2,
    The faster lens 50mmf1.2 will be the bulkier / larger diameter lens.

    Ryan

  5. #5

    Default Re: Diameter/Circumference of Lens

    Quote Originally Posted by AMediaLuz View Post
    We know that the f-stop of a lens controls how large the aperture opens to let light gets into the sensor, but I am curious if the diameter (or is it circumference) of the lens makes a difference?

    Sounds like a stupid question, but I am really curious.
    are you asking if a 67mm Tamron 17-50 f2.8 is less brighter then a 77mm EF 24-70mm f/2.8L USM?

    in general its pretty hard to say as with new methods of construction, materials used and coating.

    trend is now that manufacturers now are trying to shrink lenses as much as possible to lower costs by possibly cutting corners though i`d rather they just use the actual size.

    some people like the lens output to be brighter while others prefer very sharp but very very few can afford having both qualities so see which market segment the lens targets.
    Last edited by Reportage; 1st April 2009 at 01:13 PM.
    You wont see me much less remember me but i am the guy who makes you look good.

  6. #6
    Senior Member giantcanopy's Avatar
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    Default Re: Diameter/Circumference of Lens

    Irregardless of the focal length / size / diameter .

    Lenses with designated effectively f2.8 will give the same exposure.

    Ryan

  7. #7

    Default Re: Diameter/Circumference of Lens

    Quote Originally Posted by agws1970 View Post
    First Google hit for Focal Length F Stop

    http://www.paragon-press.com/lens/lenchart.htm

    Really learn to google okay? Hehe.
    DUDE!! I am not asking about focal length.

  8. #8

    Default Re: Diameter/Circumference of Lens

    Got that! Many thanks for the explanation, Reportage, Giant Canopy and Teebs.

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