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  #11  
Old March 24th 05, 02:37 AM
David J. Littleboy
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"rafeb" wrote:
Eric Gill wrote:

No, of course not. There is nothing about digital that makes it show

lens
defects more readily.


Actually, there's some evidence that typical
35mm lenses don't have the resolution needed
to properly "feed" the best CMOS/CCD sensors.


Yes. At frequencies up to about 2/3 of the Nyquist frequency for the sensor,
sensors are very good at taking full advantage of the MTF of the lens:
digital has much less noise than film has grain.

The interesting point is that pretty much regardless of the resolution of a
sensor, a better lens will produce a better image. This is because MTFs
combine multiplicatively: the system MTF at a given frequency is the product
of the sensor/film MTF and the lens MTF. There's a review on Luminous
Landscape of the Canon 17-35 vs. the 16-35, and the difference is clearly
visable on the 3MP D30.

So the idea that it's a _resolution_ issue is basically incorrrect, it's an
MTF issue, since better lenses have better contrast across the whole
frequency range.

There's no question that modern CMOS/CCD
sensors capture far more information
per unit area than film.


Well, no. They capture more _useful_ information, but in terms of _limiting
resolution_, film can exhibit vanishingly faint traces in resonse to
insanely high contrast targets.

The advantage of film, of course, is that
it's relatively easy to scale, simply by
moving to a larger format.


One point here, is that in both film and digital, one runs into diminishing
returns. It's harder to provide the resolution across the whole frame for
larger formats. Also, assuming the same technology, if you reduce the pixel
pitch by a factor of 1.414, you only increase the noise by a factor of
1.414, so cameras like the 300D/10D, with their usable ISO 400 and
outrageously clean ISO 100 will seem less attractive than something like the
D2x with its usable ISO 100 and 12MP. This makes the MP game a slippery
slope. So whereas you used to have an FZ10 with a respectably clean ISO 50,
you now have an extra MP and visible noise.

To get back to the diminishing returns bit, that means that you really want
a wider pixel pitch on your MF back than on your full-frame dSLR, and a
wider pixel pitch on your full-frame dSLR than your APS-C dSLR. But at which
point, since the D2x has a usable ISO 100, most people won't see the
advantage of a similarly priced full-frame camera with 16.7 MP and a
stronger AA filter (to avoid Moiré more of the time) whose only advantage is
slightly lower noise and usable higher ISOs.

(Note that the above is only significant/interesting assuming that the D2x
sensor will appear in a D100 class body, and the 1Dsmk2 sensor will appear
in a US$3,000 class body, both of which I consider likely.)

Sigh.

David J. Littleboy
Tokyo, Japan



  #12  
Old March 24th 05, 02:41 AM
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In message ,
paul wrote:

Eric Gill wrote:

There *is* an issue that makes over f/16 impractical on most digital
bodies, where a Hassy can easily do f/45. This can make a big difference
shooting certain subjects, such as rooms, when the entire field needs to
have good focus.


Why is that? I've used f/22, 36, 45 on my D70 with various lenses.
You've got to get the dust off the sensor though.


As the aperture starts to get really small, the entire image starts to
get blurrier and blurrier. There comes a point where you lose more to
diffraction than you gain by theoretical DOF.

IOW, the smaller the aperture (or higher the f-stop), the greater the
depth that is in near-maximum focus, but the less sharp that the maximum
can be.
--


John P Sheehy

  #13  
Old March 24th 05, 02:46 AM
David J. Littleboy
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wrote in message
oups.com...


"There's no question that modern CMOS/CCD sensors capture far more
information per unit area than film.

You're out of your ****ing mind. Film grains are hundreds of times
smaller than sensors.


No, he's quite right. Consider a 16x24mm area of ISO 400 film and what an
8x10 print from that would look like: seriously disgusting. Now look at an
8x10 print from a 6 or 8MP Canon or Nikon dSLR at ISO 400: maybe not as good
as MF at 8x10, but nowhere near as problematic as half-frame 35mm.

Now consider a 6.6 x 8.8 area of ISO 100 film printed at 8x10 and look at an
8x10 from the Sony F717. An even larger difference, although the Sony's
pretty poor compared to the dSLR.

David J. Littleboy

Tokyo, Japan



  #14  
Old March 24th 05, 02:46 AM
David J. Littleboy
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wrote in message
oups.com...


"There's no question that modern CMOS/CCD sensors capture far more
information per unit area than film.

You're out of your ****ing mind. Film grains are hundreds of times
smaller than sensors.


No, he's quite right. Consider a 16x24mm area of ISO 400 film and what an
8x10 print from that would look like: seriously disgusting. Now look at an
8x10 print from a 6 or 8MP Canon or Nikon dSLR at ISO 400: maybe not as good
as MF at 8x10, but nowhere near as problematic as half-frame 35mm.

Now consider a 6.6 x 8.8 area of ISO 100 film printed at 8x10 and look at an
8x10 from the Sony F717. An even larger difference, although the Sony's
pretty poor compared to the dSLR.

David J. Littleboy

Tokyo, Japan



  #15  
Old March 24th 05, 02:56 AM
Eric Gill
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rafeb wrote in news:4241fb95$0$8853
:

Actually, there's some evidence that typical
35mm lenses don't have the resolution needed
to properly "feed" the best CMOS/CCD sensors.

This debate is raging as we speak on r.p.d.


Harumph. Higher quality lenses yield higher quality images - sharper, more
vibrant color without any post processing - on my cameras, and that's all
the debate I'm interested in.

See the link I posted about the Distagon on Canon dSLR. While I would sure
as hell hope he gets even better images on that 1ds than I do on my 10 or
20D, the Distagon certainly shows its quality on any body I've tried them
on.

  #16  
Old March 24th 05, 02:56 AM
Eric Gill
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rafeb wrote in news:4241fb95$0$8853
:

Actually, there's some evidence that typical
35mm lenses don't have the resolution needed
to properly "feed" the best CMOS/CCD sensors.

This debate is raging as we speak on r.p.d.


Harumph. Higher quality lenses yield higher quality images - sharper, more
vibrant color without any post processing - on my cameras, and that's all
the debate I'm interested in.

See the link I posted about the Distagon on Canon dSLR. While I would sure
as hell hope he gets even better images on that 1ds than I do on my 10 or
20D, the Distagon certainly shows its quality on any body I've tried them
on.

  #17  
Old March 24th 05, 03:07 AM
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wrote:

"There's no question that modern CMOS/CCD sensors capture far more
information per unit area than film.


You're out of your ****ing mind. Film grains are hundreds of times
smaller than sensors.


http://groups.google.ca/groups?selm=...utpu t=gplain

"The average size of these grains varies from about 0.5 micro-metre
(um) in diameter for slow emulsions such as are used in print films, up
to about 1.5um in diameter for fast emulsions suach as are used in
X-ray films."
[...]
"The mean grain-size in emulsions used for camera films in colour
photography can be regarded as about 1 um in diameter;"

Note: pixel sizes range from 2 to 10um. I'll leave the arithmetic to
you.

 




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