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no worries.
that's correct. a constant aperture lens is a zoom lenses that can hold the same maximum aperture as you move from the wide end to the telephoto end. these are usually much more expensive than the consumer-grade lenses (i.e. f/3.5-5.6) because of the need for larger glass to maintain that larger opening for telephoto focal lengths.
aperture's are ratios of light transmission relative to the focal length. an f/2.8 on a 50mm doesn't need nearly as much area as an f/2.8 on a 200mm.
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2009 135i | space grey | sport | navi | hifi | heated
dinan stage 2 software | bmw performance exhaust
kw v2 | hotchkis front sway | vmr v710
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