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#1
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"1:" on lens label -- what does it mean?
On the front of my P/S lens, there is a label that says:
5.8-32mm 1:2.6-5.5 And on the front of my film SLR lens, the label says: 35-80mm 1:4-5.6 My question is, what does the "1:" in front of the aperture mean? Thanks, -Mike |
#2
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"1:" on lens label -- what does it mean?
"none" wrote in message
news:Hgb9f.5029$UW5.886@trndny09... On the front of my P/S lens, there is a label that says: 5.8-32mm 1:2.6-5.5 And on the front of my film SLR lens, the label says: 35-80mm 1:4-5.6 My question is, what does the "1:" in front of the aperture mean? Thanks, -Mike It's a carry over from expressing the f stop or how wide the lens can open as a ratio. On most contemporary zoom lenses, the maxim aperture or f stop gets smaller as the lens zooms out. In your case, at 35mm focal length, the maximum f stop is 4 but as you zoom out to 80mm, the f stop is smaller (higher number, huh) meaning that less light passes through the lens. Other things being equal, you need brighter light to shoot when you have the lens zoomed out to telephoto. You need more light to shoot with a "slow" lens tha thas a max aperture (opening) of f/4 or f/5.6 than you woule for one with f/1.8 or 2.8. Pick up a beginner's book on photography-- or find a website-- that will explain it in more detail if you're interested. Pat |
#3
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"1:" on lens label -- what does it mean?
In article Hgb9f.5029$UW5.886@trndny09 none writes:
$On the front of my P/S lens, there is a label that says: $5.8-32mm 1:2.6-5.5 $ $And on the front of my film SLR lens, the label says: $35-80mm 1:4-5.6 $ $My question is, what does the "1:" in front of the aperture mean? It's just a different way of writing f/, expressing it as a ratio rather than by division. f/x means the size of the aperture is the focal length divided by x; in optics, the letter f is used to denote focal length (and on some lenses, you'll actually see the focal length shown in the form "f=50mm"). 1:x means that the ratio of the aperture to the focal length is 1:x. -- Stephen M. Dunn ---------------- http://www.stevedunn.ca/ ---------------- ------------------------------------------------------------------ Say hi to my cat -- http://www.stevedunn.ca/photos/toby/ |
#4
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"1:" on lens label -- what does it mean?
On Sun, 30 Oct 2005 21:52:39 +0000, none wrote:
On the front of my P/S lens, there is a label that says: 5.8-32mm 1:2.6-5.5 And on the front of my film SLR lens, the label says: 35-80mm 1:4-5.6 My question is, what does the "1:" in front of the aperture mean? Thanks, -Mike The 1 is part of the ratio of the lens aoerture, the commonly quoted 'stops' are just the second half of the ratio. f1:2.0 just means that the aperture diameter is half the focal length of the lens. HTH -- Neil Delete delete to reply by email |
#5
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"1:" on lens label -- what does it mean?
The "1" refer to focal length.
when you set to 35mm FL means 35/4 and this is the diameter of the aperture = 8.75mm when you set to 80mm FL means 80/4 and this is the diameter of the aperture = 14.28mm when the aperture is not a circle, take the area for equilibrium. "Patrick Cleburne" mgcleburne@rebnet wrote in message ... "none" wrote in message news:Hgb9f.5029$UW5.886@trndny09... On the front of my P/S lens, there is a label that says: 5.8-32mm 1:2.6-5.5 And on the front of my film SLR lens, the label says: 35-80mm 1:4-5.6 My question is, what does the "1:" in front of the aperture mean? Thanks, -Mike It's a carry over from expressing the f stop or how wide the lens can open as a ratio. On most contemporary zoom lenses, the maxim aperture or f stop gets smaller as the lens zooms out. In your case, at 35mm focal length, the maximum f stop is 4 but as you zoom out to 80mm, the f stop is smaller (higher number, huh) meaning that less light passes through the lens. Other things being equal, you need brighter light to shoot when you have the lens zoomed out to telephoto. You need more light to shoot with a "slow" lens tha thas a max aperture (opening) of f/4 or f/5.6 than you woule for one with f/1.8 or 2.8. Pick up a beginner's book on photography-- or find a website-- that will explain it in more detail if you're interested. Pat |
#6
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"1:" on lens label -- what does it mean?
Sorry, should be 80/5.6 = 14.28mm
"kctan" wrote in message ... The "1" refer to focal length. when you set to 35mm FL means 35/4 and this is the diameter of the aperture = 8.75mm when you set to 80mm FL means 80/5.6 and this is the diameter of the aperture = 14.28mm when the aperture is not a circle, take the area for equilibrium. "Patrick Cleburne" mgcleburne@rebnet wrote in message ... "none" wrote in message news:Hgb9f.5029$UW5.886@trndny09... On the front of my P/S lens, there is a label that says: 5.8-32mm 1:2.6-5.5 And on the front of my film SLR lens, the label says: 35-80mm 1:4-5.6 My question is, what does the "1:" in front of the aperture mean? Thanks, -Mike It's a carry over from expressing the f stop or how wide the lens can open as a ratio. On most contemporary zoom lenses, the maxim aperture or f stop gets smaller as the lens zooms out. In your case, at 35mm focal length, the maximum f stop is 4 but as you zoom out to 80mm, the f stop is smaller (higher number, huh) meaning that less light passes through the lens. Other things being equal, you need brighter light to shoot when you have the lens zoomed out to telephoto. You need more light to shoot with a "slow" lens tha thas a max aperture (opening) of f/4 or f/5.6 than you woule for one with f/1.8 or 2.8. Pick up a beginner's book on photography-- or find a website-- that will explain it in more detail if you're interested. Pat |
#7
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"1:" on lens label -- what does it mean?
It is the depreciation schedule for the camera.
1:4.5 is the rate of depreciation in % for each day you own it. |
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