On Sun, Dec 31, 2000 at 02:15:27PM -0800, jldasch@xxxxxxxxxxxx wrote:
> >>>>> "C.H." == C H Ling <chling@xxxxxxxxxxxx> writes:
>
> Classical optics is an old and well understood area of physics. It is
> precisely this that allows the manufacturers to design their optics.
> With modern computer codes it is possible to accurately simulate all
> characteristics of a lens, including the imaging of out of focus
> areas, which you feel ("bokeh") can not be measured.
>
> -John
Yes, but the possiblity to simulate all characteristics of a lens, does not
mean, that
every new lens is perfect. A computer can only calculate the values of a given
design,
and might opimize one or another parameter. But it is still the lens designer,
who has
to decide, which folumla is the best suitable for a new lens, which is the best
compromise.
This decission depends a lot from his personal (or his company`s) opinion about
the
meaningfulness of a lens characteristic.
This is the information I´d like to have about a lens, MTF curves can only give
a rather
hazy idea about this.
I´ll never forget when a professor of optics told us about his unsucessful
trials to improve
old lens design from the 1950/60`s with his new computer programs. He sad, that
is was
really impossible to do this, until he added new elements (more lenses, new
glass type..).
His explanation, was that those guy`s which had to calculate every single ray
of light by
hand got by far a better understandig, of what really happes in the lens, which
enabled them
to find the best possible design, without computer aid.
Frieder Faig
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