I believe you'll find that the number of blades increases with the
diameter of the lens. Despite Acer's preference for angular highlights
the lens designer is actually trying to achieve a circular aperture as
much as possible. The greater the number of blades the closer the shape
is to a circle. Trying to stuff 8 blades into the space available in a
28mm f/3.5 (which has 6) would be hard. However, the 50mm f/1.4, the
85mm f/2 and the 135 f/3.5 all have 8 blades. They are also
approximately the same diameter with the front element filling the
available space for a 49mm filter.
Chuck Norcutt
Woburn, Massachusetts, USA
Giles wrote:
>No, because the 90mm f2 has lovely bokeh. It has nine blades and the 50mm
>f3.5 has 6.
>I reason there must be a good reason Olympus does not just use six blades on
>all
lenses.
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