Chris T Loc: from England across the pond to New England

One reads a great deal on the Net - vis a vis this problem, but one is left with a certain uncertainty. It would seem - the higher res one attains - the less the threshold, before the onset of noise. In other words, you are better off with a 12MP camera, than you are with a 24MP camera. And, conversely, you're better off with a 24MP camera, than you are with a 50MP camera, as - the higher you go up the ladder, the higher in density are the photo-sites - which, in turn - makes the onset of noise - that much sooner. Please comment, if you would like. And if you have a clear explanation of this phenomenon - please, elaborate, if you've a mind.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

You,ll need to compare apples to apples. Either downsample the 50 mp image to 12 mp or upsample the 12 mp image to 50 mp. You'll see that generational differences will be a better predictor of noise thresholds than pixel count.

RichardTaylor Loc: Sydney, Australia

Not necessarily.

A few variables:

What year was the camera made?
How large is the sensor?
How many megapixels is the sensor?
If shooting jpg, is the camera applying noise reduction when processing the captured image?

This is from personal experience, however I havn't used a camera with a very high MP count (>20.2MP).

What has been your personal experience, Chris?

I do not believe everything I read on the net.

Chris T Loc: from England across the pond to New England

Well, that sure goes a long way towards explaining this phenomenon, Gene … Kudos!!!!

Chris T Loc: from England across the pond to New England

I tend to think my lowly 12MP Canon EOS Rebel T3 does a better job of decreasing the noise issue, than ANY of my four 24MP Nikons, Richard … and that the one 16MP Nikon I have - withholds the onset of noise much sooner than any of the other DSLRs I possess - including the equal sensor Pentax K-50.

But, this isn't meant to be an expose of my cameras, Richard. It's meant to be a reaching out for a more clear explanation of why lesser-megapixel cameras (12MP-16MP) seem to do a better job of controlling the noise issue, than more recent 24MP-42MP/46MP/50MP cameras. Since the pixel-sites are smaller, for each newer generation of hi-res sensors - it would seem to be MORE difficult to control noise, as the high density pixels - are more apt to show noise at a sooner point. Thus, if one pursues the MP race - one is actually wounding oneself, in the process, and, perhaps, might've been better off, saving one's money.

RichardTaylor Loc: Sydney, Australia

That has not been my experience for the reasons given in my first post in this thread.
Also if you want, or need, more MP go with a larger sensor.

photogeneralist Loc: Lopez Island Washington State

I believe you are correct in theory. If all other variables are eliminated, then there are good and bad effects of increasing the pixels count while reducing the pixel size. Functionally each photographer must decide between increased possible detail and dynamic range/noise concerns as pixel count increases.

For many of us, the excellence of the equipment available to us renders the question irrelevant. How much resolution can we really see?. How much does dynamic range and noise limitations effect our perception of a photo. How much excellence is enough? When no more improvement is possible?
When no more improvement is detectible? By lab instruments? By human eyes? By unaided human eyes.
A what point do other aspects of viewing a photo come the weak link in the process. IE on a computer screen, prints as a 4 x 6?, 40 x 60?. billboard size?. museum exhibit?
How much increase in actual viewing pleasure would be realized if the camera sensor's exactly matched the response of a 20-20 human eye?
How much technical excellence is enough?

Regarding the optimal resolutions vs noise in regard to number of megapixels, I note that the Sony a7 III (24 mp) visual quality is judged by reviewers as nearly the equal of the Sony A7 RIII (42 mp). Same size sensor different sized pixels.

Chris T Loc: from England across the pond to New England

Richard - it seems Sony can only effect a Global Shutter on a lesser MP sensor, like the one employed in their 12MP FF a7 series. Since, THAT prospect is limited to lesser MP sensors, it stands to reason - it is NOT a good idea to go for a higher MP camera - does it not?

Chris T Loc: from England across the pond to New England

Sony seems to have something in its wide array of FF MILCs - does it not, PG? … There are several 24MP models, plus one or two 42MP models, plus a couple of 12MP models - the latter of which - seems to provide a product equal to, or better than - the 24MP and 24MP models. So, you takes your pick, there!

Choose your poison … less MP and less noise, or higher MP and more noise. You decide!!!!

Bipod

Nearly all noise in a RAW image fille is thermal noise from the sensor.
It is relate to two things sensitivity (ISO) and sensor temperature.
Cool the sensor cold enough: no more thermal noise.

In electronics, noise is measured by signal-to-noise ratio.
There is no fundemental reason why higher MP sensors should
have more noise. HOWEVER, there may be an engineering reason:
inadequate cooling. This could cause slightly more noise when
shooting a high MP sensor at high frame rates.

Sensors located inside of cameras are difficult to cool adequately
But so far as I am aware, this has been a problem mainly in
lower-end cameras with "global shutter" sensors, not DSLRs
or high end mirrorless cameras with focal plane shutters.

Phase One makes 100MP backs for medium format film cameras
(real "pro" cameras, like the Miyama and Hasselblad).
These backs have cooling fans or thermoelectric
(Peltier effect) cooling systems.

The worst case for heat would be what al ot of peoople
are running out and buying:

* Mirroless camera with no mechanical shutter
* "Global shutter" sensor
* Fast frame rate
* EVF screen located inside the camera

Think about it: the camera is a small box, probably made
out of plastic. How you gonna cool it?

There are only four ways to move heat:
* Conduction
* Convection
* Radiation
* Active cooling (refrigeration)

None of them work well nside a small plasic box: How well
does plastic conduct heat, compared to say, copper? How's
the air flow throgh that box? If the sensor radiates heat, can
the IR light escape the box? And where you going to put a
refrigeration system?

The bottom of the sensor is covered with contacts--surface-mount
pads that get soldered to the board, so there's not even anywhere
to put a heat sink.

Phase One covers the entire back of the board in a heat ink. That's
not going to fit inside a camera.

Technology isn't about buzzwords--"The Cloud", "nanocrystals", etc---
it's about engineering. You can't get four pounds of crap into a
one-pound box no matter what the marketing department decides
to call it.

Maybe having a tiny, plastic camera wasn't really such a great idea
after all. Maybe that's one reason why Phase One's sensors are so
much superior to the ones the consumer camera companies are stuffing
inside of cameras.

Be careful what you wish for--because Nikon, Canon, Sony, etc. will
give it to you. Phase One, Leica, Hasselblad, Linhof, Sinar , Lockheed
Martin will not--they customers demand top performance, not top styling.

Chris T Loc: from England across the pond to New England

Bipod … how large a heat-sink would be needed in a FF MILC or DSLR - to reduce heat-induced noise?

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

There are many sources of noise in digital images, and by far, the most often comes from underexposure of darker areas of an image - and the shot noise that becomes evident.

https://en.wikipedia.org/wiki/Image_noise

Chris T Loc: from England across the pond to New England

Actually, Gene … I seem to see noise more in lighter areas of my pictures … but, I will take a read …

Thanks for the link …

Chris T Loc: from England across the pond to New England

Since when was Phase One designated NOT to be a "consumer camera company" Bipod?

I think I missed the memo on that one. Phase One took over Mamiya. They still market the M645, but have added their own digital back to it. Their own cameras, are basically all Mamiya models, with their own digital backs built in. Leica and Hasselblad have their own priorities, it's true. The latter extends the MP race to 100MP, and Phase One will also follow suit. It's also rumored Canon will also bring a 100MP sensor to its full-frame lineup. Fuji's version for their GFX series, is also soon to hit the stores. Sinar is now part of Hasselblad, I believe. Linhof is still producing top-tier view cameras. Not sure where Lockheed Martin fits in. Didn't even know they MADE cameras … but, for sure, if they do - you're right - they are NOT a "consumer camera company" … but, the rest - sure are.

All of this is very nice, Bipod … but I'm not sure where it all fits in with solving the noise problem. But, you did hit on something, here - that heat is a prime cause of noise. We all use fans in desktop PCs to reduce noise, but this also brings with it - the quick spreading of dust - so, don't think THAT would work too well in a camera, although - it IS a thought. I suppose if it could be confined to the area behind the sensor, and insulated against the front of the sensor, it might work, though … whaddyathink, Bipod?

RichardTaylor Loc: Sydney, Australia

This statement not entirely correct.
Fans in PCs are used to keep the temperature down so the electronic components will not overheat and stop working or to fail prematurely..