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04/13/2009 11:29:11 PM · #26 |
Originally posted by BrennanOB:
My fave way of explaining the relationship between the f/stop number and the size of the aperture is that the number is the number of the size of the hole it takes to cover the (full frame) sensor. At f/2 the hole is big enough that two circles covers the sensor. At f/64 it takes 64 of those tiny holes to cover the sensor. |
So at f/4, it takes 4 "apertures" to cover the sensor? But f/4 on a 50mm lens is 12.5mm aperture, f/4 on a 200mm lens is 50mm aperture: this is not gonna hold true any way you look at it, as f/stop is a ratio, not an absolute.
My, easy rule of thumb is that the inverse of the f/stop shows you how big it is relative to the other f/stops: that is to say, 1/22 is a smaller number than 1/4, so f/22 is a lot smaller than f/4...
R.
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04/14/2009 08:17:22 AM · #27 |
Originally posted by Bear_Music:
Originally posted by BrennanOB:
My fave way of explaining the relationship between the f/stop number and the size of the aperture is that the number is the number of the size of the hole it takes to cover the (full frame) sensor. At f/2 the hole is big enough that two circles covers the sensor. At f/64 it takes 64 of those tiny holes to cover the sensor. |
So at f/4, it takes 4 "apertures" to cover the sensor? But f/4 on a 50mm lens is 12.5mm aperture, f/4 on a 200mm lens is 50mm aperture: this is not gonna hold true any way you look at it, as f/stop is a ratio, not an absolute.
My, easy rule of thumb is that the inverse of the f/stop shows you how big it is relative to the other f/stops: that is to say, 1/22 is a smaller number than 1/4, so f/22 is a lot smaller than f/4...
R. |
ehem... trying to Yanko me?
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