Pixel size more important than megapixel amount for image quality?

[tesla23]

I am trying to understand what their roles are when it comes to image quality.

thanks

 

[J A C S]

None of those factors means much without knowing the rest.

 

[Rick Knepper]

I prefer a larger number of pixels populating the sensors of my cameras b/c a very important goal to me is capturing fine detail.

I am trying to understand what their roles are when it comes to image quality.

thanks

 

[Great Bustard]

I am trying to understand what their roles are when it comes to image quality.

thanks

It's not the size of the pixel that matters, but the number of pixels that matters, and the total amount of light that all those pixels record.

Consider a 12 MP and 48 MP sensor, both with the same size. Four of the pixels on the 48 MP sensor will record the same proportion of the scene as one of the pixels from the 12 MP sensor, and also record the same amount of light. The difference is that the four pixels will record more detail than one pixel.

Now, there is another consideration: the overall noise in the photo. Most of the noise in the photo comes from the amount of light that makes up the photo -- the more light that makes up the photo, the less noisy it is -- but as mentioned above, the pixel count doesn't influence the amount of light that makes up the photo (as much as some may wish to erroneously argue otherwise). However, the sensor and supporting hardware also add in noise of their own (electronic noise), and more smaller pixels are typically more noisy than fewer larger pixels, all else equal.

On the other hand, this electronic noise plays a very small role until the light gets very low. For example, we might not notice any difference at all until we get to very high ISO settings, like ISO 6400 (FF equivalent).

On the other hand, the greater resolution of the 48 MP photo allows more aggressive noise filtering to be used. Thus, after noise filtering is judiciously applied, the 48 MP photo may well be just as noisy as the 12 MP photo but retaining more detail, or less noisy for the same amount of detail (depending on how aggressive you are with the noise filtering).

See here for a more thorough explanation and here for some excellent examples of what I'm talking about.

 

[Bobthearch]

Depends on the quality of the sensor. Modern sensor technology is perfectly capable of carrying 36mp or more on a APS-C size sensor with no loss in image quality.

Tiny cell phone sensors, on the other hand, are just about maxed out with regards to pixel density. Notice that the iPhone 6 kept the same 8 megapixels as the old iPhone 5, and even the new iPhone 7 has only 12 megapixels. It seems like their pixel density is just about plateaued.

 

[chipmaster]

You asking with reference to same sensor size? Without fixing sensor size a stupid discussion!

From my FX experience I will always pick more pixels over less in "good" light I.E. < 6400 ISO or so for my D810. Above 10000 ISO D5 or any of the sport bodies as S/N and other factors start winning.

comparing the D500 and to FX and the trade off is clear and it is a personal choice of color shift, noise, DR.

My ideal camera is a D900 36Meg sensor doing 10FPS with D5/D500 focus module and maybe a goose of the data path and expeed4s

 

[Donald B]

5years ago pixel size was important. Now its the opposite ? Go figure all the tech heads have no idea.

Cheers don

 

[rhurani]

I am trying to understand what their roles are when it comes to image quality.

thanks

 

[Max Iso]

I am trying to understand what their roles are when it comes to image quality.

thanks

--
My photos:
https://www.flickr.com/photos/derpap/

For the most part, more pixels won't hurt IQ. It's true there is a very slight increase in read noise but it's so slight it's usually not even detectable when comparing differing sensors (ie it's the smallest differentiating factor). For example, Sony's 24mp sensor when normalized at the same viewing size, has as good or better SNR than their 20mp or 16mp sensors.

A good comparison is the Sony A77 (2011 model) vs the A58 with 20mp (newer sensor), the A77 has 4mp more and still has better SNR (better at every ISO stop except 12,800 which it only loses by a hair), better color and mor DR. The best way to look at pixe counts is like you are cutting a cookie sheet. The amount of cookie doesn't really change from slicing it up.

You decide how much cookie is there when you flatten it on the sheet pan in the very beginning, how many "pixels" it's cut into is after the fact. For the most part, noise performance is dependent on how many photons your lens gathers and maybe the efficiency of the sensor, but pixel counts have little to do with that. At the absolute highest ISOs when SNR is very low, read noise might show a difference (we are talking about the top ISO stops). Even then the difference is small.

On the other hand, more pixels mean better resolving of fine detail, and the smaller the pixels get, the less need you have of AA filters = more resolution. The only real downside is the extra processing power needed. Aside from that, more pixels tends to always be better.

--
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-Custer

 

[Mike CH]

I am trying to understand what their roles are when it comes to image quality.

thanks

 

[kodakrome]

I am trying to understand what their roles are when it comes to image quality.

thanks

--
My photos:
https://www.flickr.com/photos/derpap/

You don't care about the role that sensor size plays when it comes to IQ?

 

[Rick Knepper]

bigger pixel, more light- as simple as that

This shows a lack of understanding of how to apply this fact. Please read Great Bustard's post above -> carefully.

Your statement may also indicate a a definition of image quality that is too narrow for the venue. There are many needs that may have to be served by the same sensor.

 

[rhurani]

bigger pixel, more light- as simple as that

This shows a lack of understanding of how to apply this fact. Please read Great Bustard's post above -> carefully.

Your statement may also indicate a a definition of image quality that is too narrow for the venue. There are many needs that may have to be served by the same sensor.

--
Once you've done fifty, everything else is iffy.

The guy is asking a simple question and everybody started lecturing. if you have everything else equal, the bigger sensor (of the same pixel count) gives better image quality. can you dispute that?

 

[Mark S Abeln]

Girl wants pizza sliced into eight pieces instead of twelve:

 

[J A C S]

bigger pixel, more light- as simple as that

This shows a lack of understanding of how to apply this fact. Please read Great Bustard's post above -> carefully.

Your statement may also indicate a a definition of image quality that is too narrow for the venue. There are many needs that may have to be served by the same sensor.

--
Once you've done fifty, everything else is iffy.

The guy is asking a simple question and everybody started lecturing. if you have everything else equal, the bigger sensor (of the same pixel count) gives better image quality. can you dispute that?

The guy asked a nonsense question and we are trying to decrypt it. If "everything else is equal", the sensor size is fixed and the pixel size determines the mp count; which makes his question nonsense.

 

[J A C S]

Girl wants pizza sliced into eight pieces instead of twelve:

LOL! I do not usually watch videos but this time I am glad that I did! I know this girl, she has been a regular poster here for years under different names!

Was that staged, BTW?

 

[Mark S Abeln]

I know this girl, she has been a regular poster here for years under different names!

That's just cruel

Was that staged, BTW?

I would hope so, but it seems so natural.

 

[Great Bustard]

5years ago pixel size was important. Now its the opposite ? Go figure all the tech heads have no idea.

As usual, you are mistaken. As always, the pixel size matters only inasmuch as it contributes to the total number of pixels that make up the photo. By the way, didn't know you were a girl:

;-)

 

[Great Bustard]

I am trying to understand what their roles are when it comes to image quality.

thanks

you're being fooled by the above comments, all of them. for image quality, OF COURSE pixel size that matters the most. bigger pixel, more light- as simple as that.

Speaking of simple, you're simply incorrect. Bigger pixels do not collect more light -- all else equal, of course.

 

[mosswings]

I am trying to understand what their roles are when it comes to image quality.

thanks

you're being fooled by the above comments, all of them. for image quality, OF COURSE pixel size that matters the most. bigger pixel, more light- as simple as that.

Speaking of simple, you're simply incorrect. Bigger pixels do not collect more light -- all else equal, of cours

Rhurani, take a look at the links GB posted that demonstrate the inaccuracy of your claim.