Re: Perfect lens
On Apr 1, 9:08*pm, Alfred Molon <alfred_mo...@yahoo.com> wrote:
> Just wondering, if money played no role how good could lenses be?
> No chromatic aberrations, no geometric distortions, huge sharpness from
> corner to corner even wide open, or are there some physical constraints
> which prevent from producing a perfect lens?
> Alfred Molon
> Olympus E-series DSLRs and micro 4/3 forum athttp://tech.groups.yahoo.com/group/MyOlympus/http://myolympus.org/photo sharing site
There have been essentially near perfect lenses. Nikon's ultra micros
from the 1960's purportedly had resolution 30-40% better than the best
lenses commercially available today. Uncertain of that. The guys who
did the gigapixel project had a large format lens built for them that
was better than anything on the commercial market. It cost them
$50,000, which isn't that much for a high-end, one-off. A perfect
lens (sort of) can be had today. Buy a top flight apochromatic
telescope with a triplet lens incorporating a real fluorite element of
small aperture (80-100mm) from somewhere like Telescope Engineering
Company in Colorado or APM telescopes in Germany. Expect to pay about
$4000-$6000. The scope will probably be around f5.6 or f8.0. Stop it
down one stop with an make-shift diaphragm over the front of the lens
and you'll have basically an aberration-less lens. In fact, any
decent medium focal length, high-end lens (Zeiss ZF, etc) say around
100mm stopped down to f/8.0 is for all purposes, aberration-less.
Camera companies used to make lenses like this, called "process
lenses." They were characterized by long focal ratios and very good
control of aberrations. They come up for auction sometimes.
With high-end aberration-controlled lenses, likely the only losses
will be in contrast which happens no matter how few elements you have
or how well they are coated and how well the lens is internally
baffled and blackened.
The problem, as many film users have pointed out, is that the lens is
only one part of the image equation. Everything else in the train
(monitors, printers) are the weak points, that reduce what the camera
and lens are capable of.
The makers of higher-end CCTV lenses (Schneider, for one) for industry
and science rate their lenses by megapixel, what the lens will support
when it comes to the sensor it is matched to. A 5 megapixel lens will
deliver all the detail a 5 megapixel sensor will provide, etc. You
don't see that in the consumer realm.
Your best best for lenses used wide open and having the best
aberration control are things like Zeiss Master Prime cine lenses,
which cost about $10,000 ea.
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