Olympus-OM
[Top] [All Lists]

[OM] Re: Digital imaging

Subject: [OM] Re: Digital imaging
From: Thomas Bryhn <thomas.bryhn@xxxxxxxxxx>
Date: Sun, 02 Apr 2000 17:08:35 +0200
At 03:41 02.04.00 -0700, Phillip Franklin wrote:
>
>Joseph,
>
>I think you are are some what overstating the present and near
>capabilities of ccd imaging over film.

I couldn't agree more with this statement, but not because of bandwidth and
storage space limitations. I think the problem right now is with optics and
image sensor sizes: To avoid degradation of images because of diffraction
you need a certain lens opening. For example our beloved 50/1.8 is limited
in resolution below f/8, or an equivalent ~6mm opening. For a wide angle,
21mm, the same thing should happen at around f/3. In todays cheap digital
cameras you're stuck with very short lenses because the image sensors are
so small, and an 8mm lens will be diffraction limited at ~f/1 ! This mean
we'll either have to buy *very* fast optics or accept a loss in resolution
compared to film.

The obvious solution is of course to make a CCD the size of a 135 film or
larger. You start with a polished silicon square (in real life it's a round
disc) about 100mm x 100mm that perhaps cost you $1600 (This number chosen
to make the calculations easier). You can make 100 CCDs the size of 10mm x
10mm, or you can try to make them 25mm x 25mm, and only have room for 16.
The cost per CCD is then $16 or $100.
This is an obvious difference in cost, but we've only just started: These
numbers assume you've got a perfect production environment! If you invest
*heavily* in clean room technology your 100mm x 100mm silicon square can
have -let's say - 20 microscopic specs of dust. Each of them will make a
chip unusable, and you'll be left with 80 working CCDs at $20 each, or ~4
working CCDs (one chip can have multiple specs of dust; broken or very
broken is not important) at a cost of $400 each!

High volume electronics have become cheaper and cheaper because production
technology has enabled us to pack things tighter, thus using less area and
increasing production yield at a given cleanliness at the same time. With
CCDs we should really go the oposite way if image quality is the goal, and
cost per resolution will *not* follow the same curve as cost per MIPS in
processors.

I have no doubt digital will make film obsolete in the end, but in the near
future quality per dollar will be a strong argument for film based cameras
like our OMs. When the day comes and film is "dead" I see no reason why our
Zuikos can't be used on a digital body, Olympus or third party.

Sorry for the low OM content, I'll shut up now.

Thomas Bryhn 

< 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