The old lore about slower lenses tending to be better performing than faster
lenses
may be true for other brands but it does not hold true with respect to Zuikos.
George is right, with Zuikos the lore is fallacious as the tendency is for the
faster lenses to be better performers than their slower counterparts.
It is not a simple matter of just the number of elements and light
transmission.
Gary's tests have shown that some multi element zooms rival some fixed focal
length
lenses wich have far fewer elements.
When comparing fast lenses and slower ones it is not really valid to say that
the
slower one is sharper at it's maximum aperture than the faster one is at its
maximum
aperture. The more valid comparison is to compare the lenses at equivalent
apertures. When you do this the picture changes. Looking at the performance
of a
50mm f1.2 at f1.2 might lead you to think it is a dog, but compare it at f2
with the
50mm f1.8 at f1.8 and it is the latter which starts to bark.
This tends to hold true across the line of Zuikos. As was pointed out, all
lenses
tend to be at their best when closed down one to two stops. This means that a
fast
lens will tend to achieve its best performance at a wider aperture than a
slower
one.
Giles
J. Williams wrote:
> How so? Slower lenses have fewer optical elements. Fewer elements mean
> more light transmission. F1.8 wide open should be sharper than f1.2/f1.4
> at wide open.
>
> John
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