DSLR v Consumer Image quality

"rafeb" wrote in message
. com...


C J Campbell wrote:


In what way is it better? Why does the small sensor of the human eye
have
better resolution than the large sensor of a 35 mm frame?


The human eye has this thing called
a brain behind it. The human eye has
great resolution over a very small
viewing angle. But the brain can direct
that super-sensitive area (the fovea)
instantly to where it's needed.


That explains absolutely nothing. You are saying that the human eye performs
better, despite its deficiencies, because it has better software? Well then,
why can't better software improve the picture on a small digital sensor?

In many ways the human eye is a pretty
poor design. Light actually has to
pass through a layer or two of neural
processing tissue before it lands on
the retina!

The eye in this respect is nothing but an extension of the brain. Rods
provide very rough resolution, but tremendous light sensitivity, reacting to
a single photon. The individual rods, however, are poorly connected; often
three or four rods connected to a single pathway. This inefficiency is
probably an advantage in helping to reduce noise.

"Roger N. Clark (change username to rnclark)" wrote in
message ...

Consider the "sensor size" of the eye
of an eagle, or even a human eye, and the relative quality of that
sensor
vs. any camera or film. (I suppose a human eye could be defined as a 150
MP
sensor, but only about 16 MP are used for color vision -- the rest
simply
give a rough outline of light and dark. One may note, too, that small
children, whose eyes are not fully developed, may still "see" something
like
digital noise, which disappears at about age 5 or so. The physical size
of a
human eye is not all that large; the eye of an eagle is much smaller yet
sharper with better color vision.) I wonder how much the image recorded
by
the eye could be enlarged before you began to see significant
degradation,
but I digress.

And not factual either. The human eye with normal vision has a image
resolution equivalent over 500 megapixels. See:
http://www.clarkvision.com/imagedeta...esolution.html


Does it indeed? So how does the eye achieve that resolution with only 6
million cones and somewhere between 100 million and 200 million rods -- most
of which are duplicates or not connected to anything? Maybe Mr. Clark needs
to check his figures again.

rafeb wrote:
Mostly what I thought we were discussing is
whether 100% viewing on screen was useful or
not. I maintain that it is, for critical
work, or for large prints. In my experience --
while the print is the end goal, the monitor
is a pretty good predictor of how good the
print can be. If detail or tonality aren't
there on the screen, they're not going to
magically appear on the print.


The problem is that it is easy to fool yourself into thinking there is
useful detail in a photo when there is not, when viewing it at 100% on
screen. The reason for this is simple, at 100% on screen you will see
low contrast detail because it will be fairly low in lines per inch,
but when printed this low contrast detail is no longer visible to the
human eye.

The eye can see detail to 0.7 line pairs per inch for 100% contrast, at
a light level of 23 foot lamberts, this drops to 0.4 line pairs per
inch at 10% contrast. And you can see down to less then 2% contrast if
the line pairs per inch are at 0.1.

What all this means is that you will see detail on the screen that you
will not see in the print.

So you are correct detail will not magically appear when printed, but
it will disappear.

Scott

On Tue, 22 Feb 2005 23:47:26 -0800, "Mark²" mjmorgan(lowest even number
wrote:

This is why I think anyone considering spending with[in] a few hundred dollars of the 300D or
D70 on a lesser...but sizable camera...should REALLY consider teh DSLR.
It really can open new visions for people when they experience the difference...without
having to magically "miss things" they have never even experienced.

I was in exactly this situation. I had a compact zoom film camera and
wanted to "go digital" (well, go "properly" digital -- I did have a
few-years-old 1+MP p&s, but I'd stopped using it).

Probably the main criteria was to get something "pretty decent" that would
do most of things -- at least reasonably well -- that I'd be likely to want
to do for some time to come.

For little more reason than I spotted a second-hand one in a shop, and it
looked "nice", I originally started looking at the Nikon 8700. Browsing
around the web, I was then toying between it and the 8800 (it cost more,
but had stabilisation). Almost on the verge of buying one or other of
these, I then stumbled across (among other sites) one of Ken Rockwell's
pages where he basically said the same as you: If you're going to spend
your money on [any of the 4 or 5] 8Mp prosumer fixed-lens cameras, you're
probably better spending a little bit more and getting a lower-end dSLR
(better noise, startup- and shooting-speeds etc.).

In my particular case, I also went with his (and others') opinions of the
D70 being preferable/better to the dRebel, but this isn't a Canon v. Nikon
argument -- the important issue is high-end p&s v. low-end dSLR.

Although I've not had as much chance to do as much shooting as I would like
to yet, I'm convinced I made the right choice. The D70 (in my case) allows
much greater freedom for whatever directions my future photographic desires
will take me than one of the high-end p&s would have done. I may never use
all the potential, but at least I know it's there!

Regards,
Graham Holden (g-holden AT dircon DOT co DOT uk)
--
There are 10 types of people in the world;
those that understand binary and those that don't.

Chris Brown wrote:

In article ,
rafe bustin wrote:

On Wed, 23 Feb 2005 13:41:27 GMT, Owamanga wrote:



At the very least, you should be using a large format film camera.


I do that as well. It puts these puny
6 Mpixel DSLR images in perspective.


I gave it and bought one last weekend. It's a great old thing, MPP VI,
upgraded to VII spec with the rotating international back. Two days ago, I
shut myself in my bathroom, blocked the gap under the door, turned out all
the lights, and loaded my first sheet of film. That was a bit of an
intimidating experience - I knew vaugely what to expect after unsealing the
box, but having to do it all in total darkness by feel alone was kind of
daunting. I'm hoping it'll get easier with experience. I also got a rollfilm
back for 6*7, for when I'm feeling too wimpy to use sheet film.

So far, I have spent hours playing with the camera, but have yet to take a
single exposure. How many digital cameras can you say that about? ;-)

I expect I'll be taking a picture this weekend - probably a macro of a dried
flower using the triple extension. I'm hoping my friendly local lab won't
mind me just dropping the dark slide off with them, otherwise I have no idea
how I'm going to get this processed. I don't especially fancy setting up my
own E6 darkroom.

My wife has decided that we are calling the camera, "Snapper", because
something with so much character needs a name. This is not because we expect
to use it to make expensive snapshots, but because the thing essentially
seems to be a load of springs held in formation by willpower, which leap out
and "snap" at the unwary.

Not entirely sure what I've got myself into here...


Keep me posted on your travails... by
private email if you like.

I'm all over the map with my camera gear,
it mostly depends on how much schlepping
I'm willing to do at any given moment.

LF is definitely max-schlepping.


rafe b.
http://www.terrapinphoto.com

Owamanga wrote:


There's nothing overly wrong with occasionally critiquing at 100% or
more if the possible destination print dimensions require that, but in
many cases it's like a bank teller who uses an electron microscope to
check your signature. A fine waste of time.


For 4x6" prints, most definitely a waste of time.
Maybe even for 8x10".

At this point I've sold a good number large-ish
prints (20x30", 24x36") that formerly I'd only
done at 8x10 or 12x18". I'm getting enough $
from these to where I think my on-screen viewing
time is well justified and properly compensated.


rafe b
http://www.terrapinphoto.com

On Wed, 23 Feb 2005 11:18:34 -0500, rafeb wrote:



Owamanga wrote:


Agggh! but the whole point of capturing the image (in *most* people's
use of a DSLR) is to PRINT IT.

Well, actually a lot of folks claim that
they're not interested in prints, but
rather in seeing their images on a CRT.
I'm not one of those, but it's yet
another way of "seeing" things.

As far as I know, as yet, no CRT or LCD has a 6Mpix resolution. I
guess it won't be long, but right now that's a pipe-dream.

At 100%, on an average screen at 1280x1024, you can see about 1/5th of
a 6Mpix image. This is what they are striving for?

Really?

Or is it more realistic to presume they want the entire frame to *fit*
within the resolution of the display device (would make sense wouldn't
it). In which case we need no more than 1.3Mpix.

Again, especially for these people, it comes back to the fact that
it's *pointless* critiquing this stuff at even 100%.

Yes, gamut gets compressed, yes data gets discarded, yes the frame
gets cropped slightly, yes a paper texture is introduced, yes
reflected chemical or pigment prints look different to
backlight-screen images. But we *accept* all of that because the final
product IS THE PRINT.

..if we can't see the defect in the print, then there *is no defect*.

Seems like a narrow point of view, but
maybe OK for "99.9% of users."

Okay, I'm coming down harder on this than my real opinion, (which is
somewhere in the middle) to demonstrate a point in black & white.

This argument presumes that printing
technology is static (and this includes
printer, papers, and ink) or that your
printing skills are static, or that you'd
never want to see the same image in a
larger print.

...which I believe, realistically describes the dreams and aspirations
for 99% of the photos the current user base prints.

I've been involved in the "digital darkroom"
for about seven years now. I started out
having great fun scanning 35mm film and
making 8x10" prints on an Epson 600.

Okay, I've been doing it for about 10 years, with the help of Kodak's
Photo-CDs, but only started scanning my own slides about 3 years ago
and then gained the ability to go fully digital about 6 months ago.

At this point I'm shooting everything from
35mm, a 10D, a G2, MF and LF film, and
printing on an Epson 7000, or LightJet,
Chromira, or Durst Epsilon. Maybe someday
I'll have an Epson 9600 or a Roland or
Colorspan... who knows where this
insanity will end?

My 10 year old Photo-CD images are still of high enough resolution for
an 8x10 on the best of today's commercial printers.

Anyway, *then*, when you finally have this superb printer that can do
5ft by 3ft prints, and you've got some damn big walls to hang the
stuff on, and you've found a framer who can put it behind glass for
less than $200 a throw, I'd say sure, go ahead, critique anything you
plan on sending it at 100% or more - it'll be time well spent. But
today, this just isn't realistic.

Even then, I'd question the need for the image to be good enough to
stand up to inspection from 15" away (as you do your screen today).
When I look at paintings or photos that size in exhibitions, I would
usually to maintain a distance of at least 5ft. So, critique your
screen work at a distance of 5ft and now you are being realistic.

--
Owamanga!

Graham Holden wrote:
[]
For little more reason than I spotted a second-hand one in a shop,
and it looked "nice", I originally started looking at the Nikon 8700.
Browsing around the web, I was then toying between it and the 8800
(it cost more, but had stabilisation). Almost on the verge of buying
one or other of these, I then stumbled across (among other sites) one
of Ken Rockwell's pages where he basically said the same as you: If
you're going to spend your money on [any of the 4 or 5] 8Mp prosumer
fixed-lens cameras, you're probably better spending a little bit more
and getting a lower-end dSLR (better noise, startup- and
shooting-speeds etc.).

This is only true, though, if you are prepared to accept the penalties of
interchangeable lenses, dust, size, cost, bulk, weight etc. of the
multi-lens DSLR solution. It depends on many factors including your
photographic needs and aims. One solution doesn't fit all.

David

Owamanga wrote:
[]
As far as I know, as yet, no CRT or LCD has a 6Mpix resolution. I
guess it won't be long, but right now that's a pipe-dream.

9MP monitors are already available...

http://www.pc.ibm.com/us/intellistation/t221/

David

C J Campbell wrote:

"rafeb" wrote in message
. com...


C J Campbell wrote:



In what way is it better? Why does the small sensor of the human eye

have

better resolution than the large sensor of a 35 mm frame?


The human eye has this thing called
a brain behind it. The human eye has
great resolution over a very small
viewing angle. But the brain can direct
that super-sensitive area (the fovea)
instantly to where it's needed.



That explains absolutely nothing. You are saying that the human eye performs
better, despite its deficiencies, because it has better software? Well then,
why can't better software improve the picture on a small digital sensor?


Maybe someday it will... by waving the
sensor around under the lens. But
prints-on-paper or images-on-screen are
a qualitatively different thing from
human vision (as if that even needed
saying.)


In many ways the human eye is a pretty
poor design. Light actually has to
pass through a layer or two of neural
processing tissue before it lands on
the retina!


The eye in this respect is nothing but an extension of the brain. Rods
provide very rough resolution, but tremendous light sensitivity, reacting to
a single photon. The individual rods, however, are poorly connected; often
three or four rods connected to a single pathway. This inefficiency is
probably an advantage in helping to reduce noise.


Not sure why you're making this argument.

These are the reasons why photography is
different in a hundred ways from human vision.

They've been written about and documented
extensively, not only by physiologists but
by any number of photographic experts.
Fascinating topics, for sure, but far
beyond what I've got time for.


rafe b.
http://www.terrapinphoto.com