[opendtv] Re: Red camera lenses
- From: dan.grimes@xxxxxxxx
- To: opendtv@xxxxxxxxxxxxx
- Date: Mon, 4 Jun 2007 09:35:47 -0700
"...stacked sensors allowing higher-energy colors to pass through the
layers intended for lower-energy colors (the Foveon sensor used in Sigma
cameras)..." -Mark Schubin
Regarding using film lenses with electronic sensors, as a point of
reference, keep in mind that film uses stacked layers with each layer
reacting to specific wavelengths and allowing higher energy wavelengths
through to the next emulsion layer. The thickness of these emulsion layers
and the difference in depths are considered in the design of a superior
quality lens. Films with thicker emulsion layers responded differently
because of it. This is one of the reasons why this sensor was developed.
It might be something to consider when using a film lens with a Bayer
sensor where all the sensors are on the same plane, although probably not
important since the circle of confusion of a good film lens at the Bayer
sensor's plane will likely still be small enough to keep within the
"pixel's" area. Plus, post-processing, there is lower resolution in the
chroma signal.
Which brings up another point, there can be too much resolution so that
there are artifacts generated if the lens is too sharp. Wide angle fixed
lenses would be of the most concern where the circle of confusion might
actually be sub-sensor sized. But the averaging across multiple sensors
that is used on a Bayer imager might help prevent some of these artifacts.
Dan Grimes
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