# ISO vs Megapixels



## Samerr9 (Jan 15, 2011)

Hi all, 

i just joined the forum as i really enjoyed reading through and i figured out that alot are taking it serious and reply in a great manner and alot of benifit.. so thanks..

my question is: 

We know that the camera's high ISO performance is affected when it has higher megapixels.. If i lower the size of the photos from full 18mp on my 60d to 10mp will the ISO performace be better?

Thank you in advance


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## Formatted (Jan 15, 2011)

What do you shoot? 

Are you a portrait / landscape photographer? Go for MP Count

Do you shoot sports / wildlife / low light situations? Go for ISO.

For me, I shoot wildlife and sports, I'm almost always photographing in available light, that means I'm required to be able to shoot at high ISOs!


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## PASM (Jan 15, 2011)

If a camera of 12 megapixels which has an option of shooting at lower resolution - maybe 8 megapixels or 5 megapixels, will using the lower resolution give a less noisy/ better picture?

I tend to do this, believing it does (that the photosites become logically bigger). Is this correct? 



Samerr9 said:


> Hi all,
> 
> i just joined the forum as i really enjoyed reading through and i figured out that alot are taking it serious and reply in a great manner and alot of benifit.. so thanks..
> 
> ...


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## Samerr9 (Jan 15, 2011)

Thank you, i do portraits of friends mainly and planning to try some wedding photography.. so sometimes i will be facing low light situations.. i got the 50mm 1.4 for this purpose.. but still i was wondering if it makes any effect.. thanks anyway 



Formatted said:


> What do you shoot?
> 
> Are you a portrait / landscape photographer? Go for MP Count
> 
> ...


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## Samerr9 (Jan 15, 2011)

Thanks for making the question easier

and yeah i was just wondering if this conclusion is correct thank you..


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## mjhoward (Jan 15, 2011)

Samerr9 said:


> We know that the camera's high ISO performance is affected when it has higher megapixels.. If i lower the size of the photos from full 18mp on my 60d to 10mp will the ISO performace be better?
> 
> Thank you in advance



I'm pretty sure the answer to this is no. The reason why higher megapixel cameras are generally more susceptible to noise is that the pixels are smaller and are not able to collect as much light.   Setting the resolution on your camera to a lower one doesn't make the pixels on your sensor any larger.


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## PASM (Jan 15, 2011)

Can anyone clarify this for us with certainty? I thought that the photosites are logical rather than physical. 



mjhoward said:


> Samerr9 said:
> 
> 
> > We know that the camera's high ISO performance is affected when it has higher megapixels.. If i lower the size of the photos from full 18mp on my 60d to 10mp will the ISO performace be better?
> ...



Thanks, I was wondering the same thing Samerr9.


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## KmH (Jan 15, 2011)

We have a winner!

More pixels means they are smaller and gather less light (signal) relative to the inherent niose they produce (shot noise). (Check out SNR - Signal-To-Noise-Ratio)

Another consideration is the quality of the amplifiers used on the image sensor array.

Consider: Canon's APS-C size image sensor is smaller than Nikon's, and Canon consistantly packs more MP onto those smaller image sensors meaning much smaller pixels.

Canon biases their image sensor amplifiers to ISO 100 even though with digital today - high ISO performance is sought after.

Nikon, to maximize high ISO performance biases their image sensor amplifiers to ISO 200.

It's little wonder Nikon dSLR cameras have better overall high ISO performance than Canon, and the gap was widened with the launch of Nikon's new D7000.

We can only speculate what is in store for the rumored replacements for Nikon's D300s, D700, and D3s.

Stay tuned! :thumbup:


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## Drake (Jan 15, 2011)

PASM said:


> If a camera of 12 megapixels which has an option of shooting at lower resolution - maybe 8 megapixels or 5 megapixels, will using the lower resolution give a less noisy/ better picture?
> 
> I tend to do this, believing it does (that the photosites become logically bigger). Is this correct?


No, not really. Your camera takes a full resolution photo every time you press the shutter button. Then, if you happen to have a lower resolution set in the menu, the image is resized and saved in your preferred size. The result is pretty much the same as having it save a full res photo, and then downsize in post on your computer.

As for the higher MP sensors being more prone to noise, I'd say yes and no. Theoretically more pixels mean smaller pixels, and smaller pixels mean more noise. However, the cameras with more MP are also usually newer than the ones with smaller resolution sensors. And there's progress in everything. Newer cameras feature more effective noise reduction algorithms, and the sensors themselves are also getting better with every camera generation. Basically, the new 16 or even 18 MP outperform many of the few years old 10 MP sensors in terms of high ISO performance.


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## Samerr9 (Jan 15, 2011)

KmH said:


> We have a winner!
> 
> More pixels means they are smaller and gather less light (signal) relative to the inherent niose they produce (shot noise). (Check out SNR - Signal-To-Noise-Ratio)
> 
> ...


 
I preffer Canon but i never say that Nikon is less .. however, i would like to comment back.. 

the Canon 550d,60d and 7d are 18mp and the d7000 is 16.2mp..  All the reviews show that all of these camera are doing about the same job in simular ISO ranges upto 3200.. so Canon is doing better as they are giving you the same noise lever with about 2 megapixels more! what do u think?


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## Buckster (Jan 15, 2011)

KmH said:


> Canon biases their image sensor amplifiers to ISO 100 even though with digital today - high ISO performance is sought after.
> 
> Nikon, to maximize high ISO performance biases their image sensor amplifiers to ISO 200.
> 
> It's little wonder Nikon dSLR cameras have better overall high ISO performance than Canon, and the gap was widened with the launch of Nikon's new D7000.


Ummm... the Nikon D7000:

ISO 100-6400 (plus H1 and H2 equivalent to ISO 12,800/25,600)

Not that it's a bad thing, just making conversation...


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## GeneralBenson (Jan 15, 2011)

Samerr9 said:


> KmH said:
> 
> 
> > We have a winner!
> ...



All of the comparison shots that I have seen show the D7000 being noticeably better at just about every ISO. From everything I've seen, the D7000 is a sizable step above any other aps-c camera, with the exception of the Pentax K-5, which shares the same sensor and is basically it's equal in terms of sensor performance. The D7000 has a very slight ISO advantage, and the K-5 has a very slight DR advantage. No other asp-c cameras on the market can tough either of these bodies in terms of sensor performance. But it will be interesting to see how Canon answers back.


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