Diameter/Circumference of Lens


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AMediaLuz

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Dec 3, 2008
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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.
 

agws1970

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#2
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.
 

teebs

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Apr 15, 2008
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#3
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.
 

giantcanopy

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Feb 11, 2007
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#4
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
 

Reportage

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Nov 24, 2008
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#5
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.
 

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giantcanopy

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#6
Irregardless of the focal length / size / diameter .

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

Ryan
 

AMediaLuz

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Dec 3, 2008
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#8
Got that! Many thanks for the explanation, Reportage, Giant Canopy and Teebs. ;)
 

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