[opendtv] Re: MPs back Ofcom stance on spectrum sale
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Tue, 29 May 2007 17:42:47 -0400
Mark Schubin wrote:
> How much a lens costs is a matter of many factors (including what
> the market will bear), but Bert's point, I believe, is that, for
> equivalent resolutions, larger imagers require less MTF from
> lenses to achieve the same overall MTF as smaller imager-lens
> combinations.
I think it's along the lines of what Dan Grimes alluded to. Which is,
there is a combination of size and lp/mm performance that results in
relatively low cost lenses as well as relatively large sensor sizes. And
that happy combination, surely NOT by pure accident, is where the
consumer grade equipment tends to be.
In your table, you show that the smallest sensors demand extremely high
lp/mm specs of the lens, e.g. 240 lp/mm for the 1/4" sensor. That will
push up the price of the lens and will really be challenging for MTF.
So, as things are today, moving these professional cameras more toward
the APS or 35mm sizes, or even medium format frame size, should ease the
cost pressure on the lens. As things turn out, that means bigger sensors
and bigger lenses in some cases, not the other way around.
I bought my 35mm SLR stuff before APS, when the big market volume was
35mm SLR equipment. That's largely why the prices were so attractive.
But now that digital SLRs are coming on strong, I expect prices for this
general frame size will again be very competitive. For a few years
there, point and shoot cameras were all the rage, and SLR prices really
went up.
BTW, Canon makes a "full frame" digital SLR (24 X 36mm), the EOS 5D,
12.8 Mpels. Contax, which used to make one too, the Contax N, got out of
the camera business (again).
Also BTW, Pop Photo had a big splash some time ago, when they claimed
digital cameras had finally reached parity with 35mm SLRs. I had
predicted when this would happen. It was when digital sensors reached in
the teens of Mpels. The first was, IIRC, a Kodak digital SLR, 13 Mpel
sensor. No longer in production. I figured, if good film SLRs can do the
equivalent of roughly 16 Mpels, that's what digital will have to achieve
for parity in image quality. MTF comparisons work out too, if the
digital sensors are roughly the same size as the 35mm film frame.
Bert
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts:
