Olympus-OM
[Top] [All Lists]

Re: [OM] I know Why the Big CCD Sings

Subject: Re: [OM] I know Why the Big CCD Sings
From: Andrew Fildes <afildes@xxxxxxxxxxxxxx>
Date: Thu, 21 Dec 2000 09:16:17 +1100
Er - curve the sensor? Who says it has to be flat?
Andrew


>At 12:09 PM -0800 12/20/00, Winsor Crosby wrote:
>
>>The one weakness of SLR design, I have heard it said, is the
>>requirement of the lens to be a retrofocus design in order have room
>>for the mirror/light box. Supposedly it is difficult to design such
>>a lens and to manufacture it to the same high standard as a lens for
>>a camera with an auxiliary viewing system such as a rangefinder.  A
>>secondary result is the comparatively large size of the retrofocus
>>design.  Since, apparently, an SLR design is not retrofocus enough
>>for a digital sensor, won't the problems of the design become even
>>more exaggerated as the the steepness of the angle is decreased?  If
>>so, it is understandable why a complete redesign of the camera is
>>needed for digital, ie., small sensor=small field=offset of lens
>>size increase due to more extreme retrofocus.
>
>This is a sort of scary thought, because it means that a digital camera
>with resolution close to that of a 35mm camera might end up being bigger
>than an SLR, with heavier glass. If we assume that today's pixel sizes of
>3-4 microns are a likely minimum (due to the wavelength of light and such
>things) that would mean a 4k by 6K array would be between 12x18 and 16x24mm.
>
>SLR's typical have a film-to-flange distance of 40mm or more, which means
>that the maximum angle of the light hitting the film is about 30 degrees
>(figure 20mm offset into the corner). If the maximum angle allowed for
>silicon sensors is, say, 10 degrees (I think I've seen articles that said
>7 or even less) that would mean a sensor-to-flange-equivalent distance more
>like 60-80mm. All of this is just back of the envelope, and maybe the
>extra 20-40 mm of thickness needed can be taken up somewhere else in the
>design, but I would bet on people figuring out how to build pixels with a
>wider FOV...
>
>paul
>
>--
>Paul Wallich                                           pw@xxxxxxxxx



< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >


<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz