 Mark Carter |
Lens 28-80mm - What the Fstops #s Mean Does the fstop 3.3-5.6 marking on a lens mean you can only shoot between these f stops? The camera specs say that f22 is possible.
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Sajeev S. Chacko |
No, the f-stops (3.5-5.6) means that for the wide angle zoom i.e. 28mm the maximum aperture is 3.5 and for the highest zoom i.e. 80mm the aperture is 5.6. since aperture is the ration of the focal length of the lens to the diameter (or radius, I don't remember exactly) i.e. focal length in the lens you mentioned 28-80, the diameter of the lens is fixed and hence as the focal length changes from 28mm to 80mm, the same diameter give higher aperture. on the other hand for a *ZOOM LENS* with *FIXED APERTURE* e.g. 70-200mm f/2.8, the lens opening (diameter) also increases, keeping the aperture (i.e the ratio) fixed.
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Mark O'Brien |
The previous response is correct, but to put it more simply, the lowest number shown is the MAXIMUM APERTURE for that lens, and of course, the MINIMUM APERTURE would be f/22 or f/16, depending on the lens. In the case of a variable focal length lens, the second number (i.e., 3.5-5.6) is the maximum aperture for the longest focal length.
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Sajeev Chacko |
one more point I would like to add to this what myself and Mark said. actually its always confusing by saying that SMALLEST f-stops means MAXIMUM apperture and vice versa. the same could be said as SMALLEST f-stops means LEAST the subject will be in focus and MAXIMUM f-stops means MORE of the subject in focus.
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Naomi |
If I am not mistaken the fstop and allowed light in inversely proportional. Meaning the larger the number 22 for example the less light needed. When using a longer lens in less light you want to use the smallest numbered f- stop and also adjust your shutter speed if at all possible.... N
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