Too many megapixels? Six is enough for an 8x10.

Started Apr 26, 2009 | Discussions
The Davinator
The Davinator Forum Pro • Posts: 22,234
Re: Nope. Just fine in the real world ...

Ken Phillips wrote:

... 'cuz in the real world we worry about CONTENT.
KP
--

http://www.ahomls.com/photo.htm
http://www.phillipsphotographer.com
'The urge to save humanity is always a false front for the urge to
rule it.', H. L. Mencken

-- hide signature --

Yup. Of course, given the same content for a landscape image, are you saying people will choose the lower rez version. Do you think Peter Lik's, Michael Fatali, Ansel Adams, John Sexton, Clyde Butcher's, etc, etc, etc images would hold the same impact if they were shot with a 6mp DSLR for their 30" and 40" prints?

I don't think for a moment that you're foolish enough to believe so.

 The Davinator's gear list:The Davinator's gear list
Canon EOS D30 Nikon D2X Fujifilm X-Pro1 Fujifilm X-T1 Canon EOS 10D +17 more
strawman_John Contributing Member • Posts: 967
Re: Nope. Just fine in the real world ...

I think the comment was 6mp for 10x8. Of course for big prints more resolution helps. But then SLRs start to loose out to bigger than 35mm format. But lets not open up into film V's digital

ejmartin Veteran Member • Posts: 6,274
Re: Insults never a good thing

strawman_John wrote:

It sort of shows that you are not able to continue the debate in a
reasoned manner.
--

Yeah, I regretted that after I pressed the "Post" button. But one gets tired of repeating the same posts over and over. The information you are requesting has already been posted, even in this thread, if you would bother to do your homework.

Sorry, sometimes my patience wears thin.

-- hide signature --
ejmartin Veteran Member • Posts: 6,274
Re: Simple question

strawman_John wrote:

At low light levels where noise is important. For a given sensor
technology, and micro lens technology, can you tell me that having a
bigger sensor area does not help gather light.

I never said otherwise. Having a bigger sensor does help gather light. That is not the issue under discussion. The issue is, does a sensor of a given size degrade in image quality if the pixel count is increased? The answer to that is no.

what you say has elements that are correct, but they do not
contradict or negate my point. you are just indicating the many
variables. Of course there are sensitivity differences in the various
silicon technologies, but does that negate the impact of area?

Again, sensor area is not the bone of contention. I don't think anyone here would argue that larger sensors don't have better IQ. What seems to be causing a great muddle is whether smaller pixels on a given size sensor degrades image quality. None of your examples bear upon that issue. They are beside the point; straw men that you are knocking down

-- hide signature --
ejmartin Veteran Member • Posts: 6,274
Re: Evidence.

strawman_John wrote:

ejmartin wrote:

strawman_John wrote:

OK lets take the D700 and D300 same MP about the same level of sensor
technology. Now does the D700 produce lower noise at a given ISO, of
course it does can I now have my 50$.

Noise as measured how? By pixel std dev of levels in uniform
tonality image regions? That is a skewed measure.

Why? The reason I use it is that it shows that a large surface area
gives an advantage when the pixel count is equal. It is something
that photographers can observe so is important.

When the pixel count is equal, one is comparing sensors of different sizes. Yes, larger sensor area gives an advantage. Does it follow that smaller pixels on a fixed size sensor are a disadvantage? No, it does not. Do most people understand what the pixel level std dev is measuring, and whether what it measures is an absolute measure of image quality? I think not.

Or take the Canon 50D and the 5D MII, the 5D MKII clearly produces
lower noise. In fact take the 5D MKII, and even though it suffers
from being older technology, it has lower noise than the 50D.

Ditto.

Plenty of evidence that a larger pixel area is better.

You just need to take care that you compare similar levels of silicon
development.
--

50D and 5D2 collect about the same amount of photons per unit sensor
area. Their photon shot noises will therefore be about the same. If
you want we can have a detailed discussion of the correlation or lack
thereof of pixel size and read noise, the trend of which is ISO
dependent. Did your statements apply to high ISO (say 1600) or low
ISO (say 200)?

I did a quick check and a 5D MKII has a pixel density not much
different from a 20D/30D. Would you care to show where it is
calculated that the 50D and 5D MKII have equal photon collection
levels per pixel. I agree the 50D has better micro lenses, perhaps
the interesting comparison is the 500D that looks to have a micro
lens similar to the other sensors. My statement of course applies to
high ISO, where we worry about noise.

http://astrosurf.org/buil/50d/test.htm

50D: .57 e- 14-bit ADU @ ISO 400
5D2: 1.01 e-
14-bit ADU @ ISO 400

Divide by 2 for every higher stop of ISO. Divide by pixel area to get a measure of per area efficiency; 50D pixels are 4.7µ, 5D2 pixels are 6.4µ:

50D: .0258 e- 14-bit ADU per square micron @ ISO 400
5D2: .0247 e-
14-bit ADU per square micron @ ISO 400

Essentially the same; the two sensors have the same photon collecting efficiency per unit area. Going to higher ISO divides both figures by the same factor.

Read noise at ISO 1600:

50D: 2.7 e- per pixel
5D2: 2.8 e- per pixel

To get a per area measure, divide this figure by the pixel spacing:

50D: .57
5D2: .45

The 5D2 has lower high ISO read noise; it is here that larger pixels have an advantage in currently available cameras.

For a modern SLR, ISO200 noise
is not much of an issue.

Not to those who crave dynamic range; this is governed by shadow noise.

Read noise at ISO 200:

50D: 8.2 e- 4.7µ = 1.7
5D2: 13.5 e-
6.4µ = 2.1

Smaller pixels are better at low ISO in currently available cameras.

Note also that your examples are comparisons of crop sensors to FF.
I suspect that all the folks who contend that pixel size is not a
strong factor in image noise, will readily agree that sensor size
is a strong factor in image noise.

I view that size of pixel , efficiency of micro lenses, and
electrical performance of ADC etc are important as well as MP count.
The best sensors balance all these items out.

Have you actually analyzed data, or are you supposing it to be so?

For a given print size there comes a point where adding more pixels
makes no difference to the print resolution. Achieved somewhere in
the 240 to 300 DPI range. And there is a point where making the
pixels smaller brings the system to the point for a given light level
that signal to noise ratio gets too bad and noise signals dominate.
The greater the pixel density the quicker you will hit this.

Above (elsewhere in this thread I gave the comparison of the D3 to the LX3, for an even more stark comparison) I showed that the light collection efficiency is insensitive to pixel size. Read noise trends in opposite directions depending on ISO. There is no clear correlation of pixel size to noise for a given illumination of a fixed size patch of sensor.

-- hide signature --
RedFox88 Forum Pro • Posts: 29,136
try updating the past..

bobn2 wrote:

RedFox88 wrote:

Overall it's rather well put for the average camera user and buyer.
They pack more and more pixels into P&S cameras for users that either
never print and upload 800x600 photos for photo sharing or print 4x6
that only need 2MP. True that cropping is needed sometimes so they
should make them 6 to 8MP and leave it there. Oh and put the image
sensor sizes back to 1/1.8" as a standard maybe even an occassinal
2/3"

Except that the new high MP cameras seem to outperform, in general,
the old lower MP cameras. Annoying when the truth gets in the way of
a good myth, isn't it

Unfortunately you're comparing current with the old. Unfortunately there isn't a 2/3" current sensor lower MP count camera to compare against higher MP smaller sensors. We just don't know how well a 5MP 2/3" sensor would do with current design, fabrication, and firmware.

It's very clear that as pixels get smaller, noise increases. We've seen this in aps-c and FF sensors already along with the very small P&S sensors going from just 7MP 1/1.8" sensors to 12MP 1/2.5" sensors.

Ergo607
Ergo607 Senior Member • Posts: 1,354
Re: Same goes for dynamic range and several other things

I don't think I completely follow you (must have missed a turn or two... )

All I can say is that I already have problems with the assessment of the LX3 having 10.7 stops DR (it's much lower in my experience), let alone having it some theoretical 12.3 stops...

You're theory may be right or wrong (I am hardly in any position to discuss that since I don't understand it the way you are explaning it), but the practice surely doesn't follow...

Daniel Browning wrote:

Ergo607 wrote:

You're just talking noise in all this. As if that was the most
important factor. I couldn't care less... Talk about DR and come back
then...

Everything said applies to dynamic range as well.

In linear image sensors, dynamic range is simply a function of noise
and light. Noise is determined by quantum efficiency (QE, for the
photon shot noise) and electronics (for the read noise). Light is
determined by the full well capacity and QE.

Full well capacity and QE scales with pixel size, so the only other
factor for dynamic range is read noise. Most discussions of dynamic
range are with regards to ample-light scenes such as outdoors,
studio, etc., so we'll assume ample light and base amplification.
We'll use 1:1 S/N as the lower end of the dynamic range.

Compare the 2-micron pixels of the LX3 (10.7 stops DR) with the
immensely larger 6.4 micron pixels of the 5D2 (11.1 stops DR). Going
by the per-pixel numbers, it seems that the smaller LX3 pixels have
less dynamic range. But remember that the LX3-sized pixel samples a
much, much higher spatial frequency. [See math below if you want the
numbers.]

At the same spatial frequency, the scaled LX3 pixels have 12.3 stops
of dynamic range, 1.2 stops greater.
--
Daniel

5D2 maximum signal: 52,300 e-
LX3 maximum signal: 9,000 e-

5D2 read noise at base ISO: 23.5 e-
LX3 read noise at base ISO: 5.6 e-

5D2 per-pixel DR at base ISO: 11.1 stops (log_2(52300/23.5))
LX3 per-pixel DR at base ISO: 10.7 stops (log_2(9000/5.6))

LX3 scaled maximum signal: 92200 (9000 e- * (6.4µm/2.0µm)^2)
LX3 scaled read noise at base ISO: 17.92 (sqrt(5.6 e-^2 *
((6.4µm/2.0µm)^2)))
LX3 scaled DR at base ISO: 12.3 stops (log_2(92200/17.92))

 Ergo607's gear list:Ergo607's gear list
Pentax K-1 II Pentax K-3 Pentax *ist D HD Pentax-DA 20-40mm F2.8-4 ED Limited DC WR Pentax smc DA 35mm F2.4 AL +5 more
Oly Canikon
Oly Canikon Senior Member • Posts: 1,278
Re: try updating the past..

RedFox88 wrote:

bobn2 wrote:

RedFox88 wrote:

Overall it's rather well put for the average camera user and buyer.
They pack more and more pixels into P&S cameras for users that either
never print and upload 800x600 photos for photo sharing or print 4x6
that only need 2MP. True that cropping is needed sometimes so they
should make them 6 to 8MP and leave it there. Oh and put the image
sensor sizes back to 1/1.8" as a standard maybe even an occassinal
2/3"

Except that the new high MP cameras seem to outperform, in general,
the old lower MP cameras. Annoying when the truth gets in the way of
a good myth, isn't it

Unfortunately you're comparing current with the old. Unfortunately
there isn't a 2/3" current sensor lower MP count camera to compare
against higher MP smaller sensors. We just don't know how well a 5MP
2/3" sensor would do with current design, fabrication, and firmware.

It's very clear that as pixels get smaller, noise increases. We've
seen this in aps-c and FF sensors already along with the very small
P&S sensors going from just 7MP 1/1.8" sensors to 12MP 1/2.5" sensors.

-- hide signature --

The reason you see an increase in noise in the examples you cite is because of the smaller sensor not the pixel size.

RedFox88 Forum Pro • Posts: 29,136
they go hand in hand!

Oly Canikon wrote:

RedFox88 wrote:

bobn2 wrote:

RedFox88 wrote:

Overall it's rather well put for the average camera user and buyer.
They pack more and more pixels into P&S cameras for users that either
never print and upload 800x600 photos for photo sharing or print 4x6
that only need 2MP. True that cropping is needed sometimes so they
should make them 6 to 8MP and leave it there. Oh and put the image
sensor sizes back to 1/1.8" as a standard maybe even an occassinal
2/3"

Except that the new high MP cameras seem to outperform, in general,
the old lower MP cameras. Annoying when the truth gets in the way of
a good myth, isn't it

Unfortunately you're comparing current with the old. Unfortunately
there isn't a 2/3" current sensor lower MP count camera to compare
against higher MP smaller sensors. We just don't know how well a 5MP
2/3" sensor would do with current design, fabrication, and firmware.

It's very clear that as pixels get smaller, noise increases. We've
seen this in aps-c and FF sensors already along with the very small
P&S sensors going from just 7MP 1/1.8" sensors to 12MP 1/2.5" sensors.

Why does the 50D have more noise than the 30D? The sensor size didn't change but the pixels got a lot smaller. Even compare the d3 vs. the d3x. d3 is cleaner and the sensor size didn't change, but obviously the pixels had to get smaller to fix twice as many in!

And you can't go from a 10MP 1/1.8" sensor to a 10MP 1/2.5" sensor without also making the pixels smaller!

Oly Canikon
Oly Canikon Senior Member • Posts: 1,278
Re: they go hand in hand!

RedFox88 wrote:

Oly Canikon wrote:

RedFox88 wrote:

bobn2 wrote:

RedFox88 wrote:

Overall it's rather well put for the average camera user and buyer.
They pack more and more pixels into P&S cameras for users that either
never print and upload 800x600 photos for photo sharing or print 4x6
that only need 2MP. True that cropping is needed sometimes so they
should make them 6 to 8MP and leave it there. Oh and put the image
sensor sizes back to 1/1.8" as a standard maybe even an occassinal
2/3"

Except that the new high MP cameras seem to outperform, in general,
the old lower MP cameras. Annoying when the truth gets in the way of
a good myth, isn't it

Unfortunately you're comparing current with the old. Unfortunately
there isn't a 2/3" current sensor lower MP count camera to compare
against higher MP smaller sensors. We just don't know how well a 5MP
2/3" sensor would do with current design, fabrication, and firmware.

It's very clear that as pixels get smaller, noise increases. We've
seen this in aps-c and FF sensors already along with the very small
P&S sensors going from just 7MP 1/1.8" sensors to 12MP 1/2.5" sensors.

Why does the 50D have more noise than the 30D? The sensor size didn't
change but the pixels got a lot smaller. Even compare the d3 vs. the
d3x. d3 is cleaner and the sensor size didn't change, but obviously
the pixels had to get smaller to fix twice as many in!

The 50D doesn't have more noise than the 30D.

I stated before that there are many design factors that change along with the number of pixels so these comparisons fall apart. The D3 and D3x are optimized for different purposes but the noise levels aren't all that different.

And you can't go from a 10MP 1/1.8" sensor to a 10MP 1/2.5" sensor
without also making the pixels smaller!

Can't argue with that. But what exactly does it prove?

RedFox88 Forum Pro • Posts: 29,136
Re: they go hand in hand!

Oly Canikon wrote:

Why does the 50D have more noise than the 30D? The sensor size didn't
change but the pixels got a lot smaller. Even compare the d3 vs. the
d3x. d3 is cleaner and the sensor size didn't change, but obviously
the pixels had to get smaller to fix twice as many in!

The 50D doesn't have more noise than the 30D.
I stated before that there are many design factors that change along
with the number of pixels so these comparisons fall apart. The D3 and
D3x are optimized for different purposes but the noise levels aren't
all that different.

Tell that to the DPR review team. Their reviews show the 40D has more noise than the 20/30D, and the 50D has more noise than the 40D. Some users say the 50D has less noise than the older advanced amateur camera line but are they being fooled by noise reduction? Other users say 50D has more noise.

See the latter half of this page, it shows the d3x with notable more noise than the d3
http://www.dpreview.com/reviews/nikond3x/page17.asp

And you can't go from a 10MP 1/1.8" sensor to a 10MP 1/2.5" sensor
without also making the pixels smaller!

Can't argue with that. But what exactly does it prove?

You said it's the smaller sensor adding the noise not the smaller pixels, but you can't have the above situation without also making pixels smaller! Smaller pixels see less light (spreading the light over smaller observable units).

Daniel Browning Senior Member • Posts: 1,058
Dynamic range, 1:1 S/N, and charts

Ergo607 wrote:

All I can say is that I already have problems with the assessment of
the LX3 having 10.7 stops DR (it's much lower in my experience), let
alone having it some theoretical 12.3 stops...

This is essentially because you and I are talking about a different "standard" of what's acceptable for noise. Let me explain.

Raw files have no such thing as "black". It just goes from white to noise. So to make an image, on must choose where to place black. It could be placed 7 stops below clipping, and that would result in 7 stops of dynamic range. The more stops down you go, the more noisy the image looks. On the LX3, 8.5 stops down from clipping, the noise is pretty bad. that's probably about the spot that most people would place black on a raw conversion. Furthermore, a curve will be used to crush the lower stops (from 6.0 to 8.5, say) and make what noise there is even less visible.

There may be plenty of visible detail if you go further. At 10.7 stops, the noise is in equal competition with signal (1:1 S/N). This is the point at which it is convention to draw the line for dynamic range. But it's just convention, it's possible to go even further. Since S/N doubles for every four-fold decrease in resolution (0.5X spatial frequency), greater dynamic range can be used for images with lower spatial frequencies. That is, using 10.7 stops dynamic range for a 30x20 print might be too noisy for the taste of most folks. But in a wallet size print it looks fine, perhaps even 11.7 stops would look noise-free. Since the spatial frequency is lower, so too noise is lower. (This is a linear-raw-only advantage. Nonlinear formats such as film have the respones curve built into the capture medium, so it's not possible to trade resolution for noise.)

You probably use something higher than 1:1 for the lower bound of your dynamic range, depending on how much noise you can tolerate in your shadows. Since everyone has a different sense of taste and preference with regard to shadow noise, it's common to use the 1:1 convention when a monolithic number is required.

However, a monolithic "dynamic range in stops" number is not enough to tell the whole story of course, just as MTF-50 cannot tell the entire story of a lens. It's highly useful to plot S/N over the entire exposure range to see how dynamic range changes for a given lower bound in S/N. That is similar to how it's useful to plot MTF over the entire Image Height and/or spatial frequency.

Look at Emil Martinec's S/N plot of the LX3 from the following post, for example:

http://forums.dpreview.com/forums/read.asp?forum=1033&message=29866728

[This has nothing to do with pixel size, by the way, just trying to share information about dynamic range.]

1:1 S/N is bold horizontal line. The blue line intersects 1:1 at 1.5. 12 minus 1.5 = 10.5, which is about the same as 10.7 above. But what if a photographer can't stand the sight of any noise in their shadows, and they prefer an minimum of 8:1 S/N for their darkest shadows? That would be a S/N of 3 stops (2:1 -> 4:1 -> 8:1). At this level, the blue line is at 5.5. 12-5.5 = 6.5. So Dynamic range drops to just 6.5 stops. Other cameras and sensor sizes plot out differently, so the rate of change for dynamic range with exposure can be different.

I hope that helps.
--
Daniel

Oly Canikon
Oly Canikon Senior Member • Posts: 1,278
Re: they go hand in hand!

RedFox88 wrote:

Oly Canikon wrote:

Why does the 50D have more noise than the 30D? The sensor size didn't
change but the pixels got a lot smaller. Even compare the d3 vs. the
d3x. d3 is cleaner and the sensor size didn't change, but obviously
the pixels had to get smaller to fix twice as many in!

The 50D doesn't have more noise than the 30D.
I stated before that there are many design factors that change along
with the number of pixels so these comparisons fall apart. The D3 and
D3x are optimized for different purposes but the noise levels aren't
all that different.

Tell that to the DPR review team. Their reviews show the 40D has more
noise than the 20/30D, and the 50D has more noise than the 40D. Some
users say the 50D has less noise than the older advanced amateur
camera line but are they being fooled by noise reduction? Other
users say 50D has more noise.

See the latter half of this page, it shows the d3x with notable more
noise than the d3
http://www.dpreview.com/reviews/nikond3x/page17.asp

The test methodology is flawed. They are comparing different size crops. See below.

And you can't go from a 10MP 1/1.8" sensor to a 10MP 1/2.5" sensor
without also making the pixels smaller!

Can't argue with that. But what exactly does it prove?

You said it's the smaller sensor adding the noise not the smaller
pixels, but you can't have the above situation without also making
pixels smaller! Smaller pixels see less light (spreading the light
over smaller observable units).

You have smaller pixels each gathering less light but more of them so you are back where you started. The same amount of light falls on a given area. That area just happens to be divided into smaller parts. The only reason you might have less light overall is with loss in the gaps but with gapless microlens that isn't an issue.

Now if you look at the individual pixel you will see more noise. But why would you do that? When you increase the number of pixels it doesn't automatically mean you have to print bigger. It means you get better quality with the same print size.

No reason to expect more noise. It just means that you average more sensor pixels to make a dot on the final print. The amount of light that makes up that dot is the same. So the signal to noise has to be the same.

RedFox88 Forum Pro • Posts: 29,136
Re: they go hand in hand!

Oly Canikon wrote:

RedFox88 wrote:

Oly Canikon wrote:

Why does the 50D have more noise than the 30D? The sensor size didn't
change but the pixels got a lot smaller. Even compare the d3 vs. the
d3x. d3 is cleaner and the sensor size didn't change, but obviously
the pixels had to get smaller to fix twice as many in!

The 50D doesn't have more noise than the 30D.
I stated before that there are many design factors that change along
with the number of pixels so these comparisons fall apart. The D3 and
D3x are optimized for different purposes but the noise levels aren't
all that different.

Tell that to the DPR review team. Their reviews show the 40D has more
noise than the 20/30D, and the 50D has more noise than the 40D. Some
users say the 50D has less noise than the older advanced amateur
camera line but are they being fooled by noise reduction? Other
users say 50D has more noise.

See the latter half of this page, it shows the d3x with notable more
noise than the d3
http://www.dpreview.com/reviews/nikond3x/page17.asp

The test methodology is flawed. They are comparing different size
crops. See below.

Lol, why don't you leave DPR on their feedback function if you think they are so wrong. Maybe they'll hire you to do their testing.

And you can't go from a 10MP 1/1.8" sensor to a 10MP 1/2.5" sensor
without also making the pixels smaller!

Can't argue with that. But what exactly does it prove?

You said it's the smaller sensor adding the noise not the smaller
pixels, but you can't have the above situation without also making
pixels smaller! Smaller pixels see less light (spreading the light
over smaller observable units).

You have smaller pixels each gathering less light but more of them so
you are back where you started. The same amount of light falls on a
given area. That area just happens to be divided into smaller parts.
The only reason you might have less light overall is with loss in the
gaps but with gapless microlens that isn't an issue.

Now if you look at the individual pixel you will see more noise. But
why would you do that? When you increase the number of pixels it
doesn't automatically mean you have to print bigger. It means you get
better quality with the same print size.

It's obvious there's no getting through to you. Good luck with that.

No reason to expect more noise. It just means that you average more
sensor pixels to make a dot on the final print. The amount of light
that makes up that dot is the same. So the signal to noise has to be
the same.

Again you feel you know more than this site that does about the more in depth analysis of digital cameras for 10 years now. Another armchair camera tester.

Oly Canikon
Oly Canikon Senior Member • Posts: 1,278
Re: they go hand in hand!

RedFox88 wrote:

Oly Canikon wrote:

RedFox88 wrote:

Oly Canikon wrote:

Why does the 50D have more noise than the 30D? The sensor size didn't
change but the pixels got a lot smaller. Even compare the d3 vs. the
d3x. d3 is cleaner and the sensor size didn't change, but obviously
the pixels had to get smaller to fix twice as many in!

The 50D doesn't have more noise than the 30D.
I stated before that there are many design factors that change along
with the number of pixels so these comparisons fall apart. The D3 and
D3x are optimized for different purposes but the noise levels aren't
all that different.

Tell that to the DPR review team. Their reviews show the 40D has more
noise than the 20/30D, and the 50D has more noise than the 40D. Some
users say the 50D has less noise than the older advanced amateur
camera line but are they being fooled by noise reduction? Other
users say 50D has more noise.

See the latter half of this page, it shows the d3x with notable more
noise than the d3
http://www.dpreview.com/reviews/nikond3x/page17.asp

The test methodology is flawed. They are comparing different size
crops. See below.

Lol, why don't you leave DPR on their feedback function if you think
they are so wrong. Maybe they'll hire you to do their testing.

And you can't go from a 10MP 1/1.8" sensor to a 10MP 1/2.5" sensor
without also making the pixels smaller!

Can't argue with that. But what exactly does it prove?

You said it's the smaller sensor adding the noise not the smaller
pixels, but you can't have the above situation without also making
pixels smaller! Smaller pixels see less light (spreading the light
over smaller observable units).

You have smaller pixels each gathering less light but more of them so
you are back where you started. The same amount of light falls on a
given area. That area just happens to be divided into smaller parts.
The only reason you might have less light overall is with loss in the
gaps but with gapless microlens that isn't an issue.

Now if you look at the individual pixel you will see more noise. But
why would you do that? When you increase the number of pixels it
doesn't automatically mean you have to print bigger. It means you get
better quality with the same print size.

It's obvious there's no getting through to you. Good luck with that.

No reason to expect more noise. It just means that you average more
sensor pixels to make a dot on the final print. The amount of light
that makes up that dot is the same. So the signal to noise has to be
the same.

Again you feel you know more than this site that does about the more
in depth analysis of digital cameras for 10 years now. Another
armchair camera tester.

This type of reply says a lot.

I was trying to have a friendly discussion. I am open to a persuasive argument. Tell me where my previous post is wrong. I prefer that to having you just lash out. Maybe you're backed into a corner?

I don't think I know more than the official testers but I can see a glaring error in their method. I mean think about it, what sense is there in comparing two dramatically different crops and then drawing conclusions.

igb Senior Member • Posts: 2,637
I'm about to hit the complaint button for the first time

R Butler wrote:

re: ejmartin

I'll try to find a moment to read those posts in more depth.
Ultimately, though, my initial scan through suggests that much of the
disagreement comes down to the per area/per pixel argument. And while
it's by no means flawless, there are arguments in favour of a
per-pixel assessment of image quality and strong arguments against us
changing. Which isn't to say we're incapable of listening to reason.

Unfortunately, I've had to delete my early, longer response as, in
hindsight, I felt my tone was inappropriate and I was risking
becoming defensive as a result of the rather belligerent style of
some forum posters we encounter.

You're offending everyone's intelligence. You have to resort to innuendos? Talk about tone.
--
-------------------------------------------------------
My Galleries: http://webs.ono.com/igonzalezbordes/index.html

S p i t z e r Forum Member • Posts: 92
Re: Bad example

strawman_John wrote:

The example linked to is more about ADC system noise than sensor
noise. you see there is so little signal what you are seeing is noise
in the ADC system and electronics, no surprise a similar result
because that test by John takes out the sensor as a significant input.

Shot noise is a function of the total light, and both images received the same amount of total light as they were the same exposure, so the shot noise was the same for each.

I can and have done a simple test. Here is examples of why you need
no more than 6mp for a 10x8 print. I took the same view with the same
lens at the same ISO (ISO 100) on a 300D and a 40D. Printed at 10x8 I
could not see any difference in resolvable noise and detail in the
print.

This is not the issue at hand. An 8x10 print will render 325 PPI on a 40D and 250 PPI from a 300D -- I doubt you can tell the difference. The issue is that more pixels do not result in more noise at the same level of detail.

So to take your arguments apart, I can see the logic of for 10x8
prints about 6mp marks the point of no more benefit for more pixels.
In fact as you make the pixels smaller the dynamic range falls off.
The noise you can combat, to an extent by applying more filtration,
swapping resolution for lower noise.

The DR for the entire image is not adversely affected by more pixels, either.

And if it helps, I do have an electronics degree, a couple of
patents and have even designed imaging equipment, so I get the maths
behind all this also.

Excellent.

So if you want to convince me that for a given sensor technology step
smaller pixels do not mean more noise and lower dynamic range, and
that for a given print size more pixels always make for a better
picture (once you have factored in lens limitations also) please send
me the maths.

The maths have already been provided in this thread (in more than one place, as I recall) by Bob. In addition, tests and charts have been provided as well. What I have not seen is an image made with fewer pixels having "higher IQ" than an image made with more pixels, which is what Bob has been arguing, but examples to the contrary have been presented.

Whether or not one "needs" more than 6 MP for an 8x10 print is an entirely different matter. For the record, in my opinion, I don't think it makes any discernable difference unless heavy cropping is taking place. But more pixels most certainly do not hurt, and that was the argument being put forth.

VTL Regular Member • Posts: 118
Re: Diminishing returns and the speed / file size issue

Daniel Browning wrote:

The only exception I can think of is cropping in ample light. [...]

This is a good point. For their needs, I don't even think that some "digital zooming" is necessarily a bad thing either, given the relative abundance of resolution (for small prints or on-screen use). Sure, they could crop, but that's not trouble they want to go to. Moreover, there are framing, metering, and focusing advantages.

Instead, since optical zooming has been held up as universally superior, we get super-tele-zooms which are of quite dubious quality at their tele ends. It might well be better in terms of image quality to have slightly more modest zoom ranges combined with digital zooming -- certainly for "average" pictures (not taken at the far tele end) and possibly even when fully zoomed in (possibly with some "digital zooming").

Serious shooters are also allergic to digital zooming, but I wouldn't mind having it in an EVF camera, so long as the RAW file could optionally capture everything (but recording the crop). As I said, there are advantages in framing, metering, and focusing.

Let's address the computer speed problem first, [...]

Of course, computer speed is an issue, but somehow it's not the one which concerns me most. There are certainly software issues (i.e., lack of parallelism), but think the situation has gotten any worse from a relative point of view.

The camera speed and storage problems can be solved with intelligent
compression.

Storage issues, along with associated issues such as transmission (across networks, for example) are a bigger issue for me. With the usual RAW formats and high-resolution cameras, hard drives can fill up awfully quickly. Arguably, it hasn't gotten any worse, relatively speaking -- but if one wants to keep one's entire photo library handy (let's say, since we're talking about convenience, on a laptop), it sure has. Without the increased resolution, the growth in storage capacities can keep up with the growth in the photo library of a relatively modest shooter like me. With increased resolution, the situation becomes rather hopeless, at least without better compression.

Unfortunately, the "serious photography" world is wedded to the current, supposedly-lossless RAW formats ("supposedly", since some pre-processing of the supposedly-raw data seems to be becoming the norm). This limits to some large extent how compressible the data is. On the other hand, if one were to accept lossy compression, the situation would become much better storage-wise. I would accept in-camera demosaic-ing and subsequent lossy compression, so long as the format could encode the full dynamic range with sufficient precision. There's currently no good middle ground between JPEG and RAW.

As you said, it's a software issue, in this case also software in the camera (plus any associated hardware acceleration necessary, I suppose). But it's also a problem of mindset -- as long as "serious photographers" insist on fully lossless RAW formats, we'll have to contend with much-larger-than-necessary files.

Camera design should not be limited due to known deficiencies in
software design.

I would argue that software design is now a part of camera design! Unfortunately, the hardware aspect outstrips the software.

A full-frame DSLR with the same pixel density as the 50D is 38.4 MP.
So if 15 MP is enough for the 50D, I would think that 38.4 MP
(15*1.6^2) would be about the same for full frame.

To be a little more conservative and practical, one should point out that one doesn't expect larger-format lenses to provide the same absolute resolution. Admittedly, there are gains in the central part of the image -- which is usually most important anyhow -- beyond what I said. Nonetheless, since people don't typically want to use much larger and much more expensive lenses (cost perhaps being a cubic function of linear size) on full-frame, this somewhat limits the resolution attained on full-frame, especially at the borders.

If one wants to have full chroma
resolution with a Bayer sensor, it's necessary to oversample even
more.

There's no doubt that the actual resolution of images from Bayer sensors is much lower than indicated. I would argue that the lower chroma resolution is no bad thing. Possibly, I could accept a compromise which skews even more heavily in favour of luminance resolution.

What I would really like is for camera and sensor manufacturers to go beyond the basic Bayer sensor. At the present, I would like greater dynamic range far more than greater resolution, for example. Unfortunately, the way the software infrastructure is set up ties us to Bayer sensors. If one were to produce a non-Bayer sensor, one would also have to convince all the software makers to figure out how to demosiac it, under the current RAW paradigm. This is an argument for in-camera demosaic-ing.

I suppose I feel that there's been too much emphasis on resolution. But you're right -- the problem lies in part with the software, and the way the software infrastructure is set up. Probably, part of the reason for the almost purely resolution-based race is that it doesn't require any change in the software infrastructure. Producing a new, higher-resolution sensor is a self-contained advancement (which is made practical by Moore's Law).

Other than workflow issues, I don't object to higher resolutions -- but I'd rather have, in most circumstances, greater dynamic range (for example). I don't think resolution should be the current priority in sensor development. For example, I'd rather Nikon take the D300 and significantly improve its dynamic range while keeping it at 12 MP, rather than moving to 15 MP with no significant improvement in dynamic range. Alas, the latter is much easier for them and much more likely.

igb Senior Member • Posts: 2,637
Back in my day

misha marinsky3 wrote:

If this is wrong, provide the link so I can learn. Just don't tell me
off - I want to learn. Don't be petulant.

when you wanted to learn from someone, you didn't try to impose your conditions.
--
-------------------------------------------------------
My Galleries: http://webs.ono.com/igonzalezbordes/index.html

bobn2
bobn2 Forum Pro • Posts: 61,424
Re: Insults never a good thing

ejmartin wrote:

strawman_John wrote:

It sort of shows that you are not able to continue the debate in a
reasoned manner.
--

Yeah, I regretted that after I pressed the "Post" button. But one
gets tired of repeating the same posts over and over. The
information you are requesting has already been posted, even in this
thread, if you would bother to do your homework.

Sorry, sometimes my patience wears thin.

Tell you what, Emil, next thread on this, I'll let you be the bad cop, and I'll have a go at being the good cop.

-- hide signature --

Bob

Keyboard shortcuts:
FForum MMy threads