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Old Feb 5, 2006, 1:51 PM   #1
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Three years ago I bought a Nikon Coolpix 2500 with 2 megapixels. Last month, for half the price, my son bought a Canon Powershot A95 with 5 megapixels. I thought it would be interesting to take some photos with both and make comparisons.

Usually the photos made by both cameras looked just as good when viewed at ‘fit to screen' size. But when I zoomed in on parts of the photos at 100% or greater the Canon photos were superior. In the Nikon photos some straight lines and flat planes became untidy, but were still clear in the equivalent Canon photo at the same magnification.


But there was one important exception to this rule: photos taken in art galleries without flash or tripod. I do this a lot; it's permitted in this country. Of course camera shake is a problem. If 40% of my photos are reasonably sharp I'm happy to discard the rest. I found by experiment that in order to achieve this kind of hit-rate I had to set the Nikon and the Canon to ISO400 sensitivity.

Used at ISO400 under these conditions most photos contained some degree of noise (ie picture breaking up into dots, often of irrelevant colours; breakup into irrelevant regular shapes). Although just about acceptable, at ‘fit to screen' size, there was more noise apparent in the Canon photos. As soon as I zoomed in, I could see that the Canon photos were much noisier than the Nikon.

From the above I drew the following tentative conclusions:
  • In general, other things being equal, the more megapixels a digital camera has, the HIGHER the quality of the image - provided the camera is not used at ISO400 or higher. [/*]
  • But when used at ISO400 or higher, in general, other things being equal, the more megapixels a digital camera has, the LOWER the quality of the image.[/*]
I'd be really grateful if anyone could tell me if these conclusions make sense. If they do, then I can reason a bit further. But first I'd like to know what you think of the above.
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Old Feb 5, 2006, 2:01 PM   #2
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Ok... just to make a point.. This is from a 3 mp camera that was purchased at a liquidation outlett. final sale.. brand new in box.. CHEAP camera.

Believe it or not.. flash was fired too..lol


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Old Feb 5, 2006, 2:02 PM   #3
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This was taken from my 1.3 mp camera on my phone. (motorola E18)
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Old Feb 5, 2006, 2:03 PM   #4
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Considering the quality is comparable on those.. This was taken with my 3mp Sony P71
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Old Feb 5, 2006, 2:04 PM   #5
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Here's an indoor shot.. to make it a little more fair. Low light.
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Old Feb 5, 2006, 2:07 PM   #6
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So.. that being said.. In the end.. mp do matter a bit.. but the camera also has to be of quality too. The sensor for example needs to 'keep up' with the photo it's taking.

Right now I think R&D feels that people want MORE PIXELS.. Sure enough.. The regular joe will take the 10mp camera over the 5mp camera if they're in the same price range.. Thinking that they'll get a better picture, when it fact thats not true.

Realisitically, most users don't need much more than 3mp.. My Sony got me through thousands of photos.. I've recently upgraded to 5mp.. but can't see wanting to go higher than that.. But I did more research on the camera.. than the mp it has.

Hope that helped a tiny bit.. Hopefully someone else will post more indepth.
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Old Feb 5, 2006, 2:17 PM   #7
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So what did that just prove? Let's see...four different subjects, some inside, some outside, some with flash, some without, four different cameras...wait, don't tell me...based on that scientific evidence, the Canon S2 IS is the world's greatest camera - right? And by the way, "low light" pics taken with flash aren't really low light, are they? Try it without flash and we'll see some noise.

Bart,

The two cameras you're comparing have different size sensors, so you can't really compare the two and arrive at your conclusions. If both had the same size sensor, the one with more MP would generally be noisier, irregardless of ISO setting. Higher ISO just shows it off more. Some cameras start to show noise at as little as 100 ISO.

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Old Feb 5, 2006, 2:22 PM   #8
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Bart150 wrote:
Quote:
From the above I drew the following tentative conclusions:
  • In general, other things being equal, the more megapixels a digital camera has, the HIGHER the quality of the image - provided the camera is not used at ISO400 or higher. [/*]
  • But when used at ISO400 or higher, in general, other things being equal, the more megapixels a digital camera has, the LOWER the quality of the image.[/*]
Bart150

Your conclusions are valid, if the sensor size is the same. This is because the individual pixels in the hi-res cameras are so small that they do not receive enough light to produce a clean signal, the result is noise. This is the reason why the DSLRs produce better pictures, big sensors. Your Nikon had a very small 1/2.7" sensor, but only 2.1MP, the Canon had a marginally larger 1/1.8" with 5MP, much smaller individual pixels.

Ira


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Old Feb 5, 2006, 2:22 PM   #9
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The point I was making (which he was asking).. is regarding megapixels.. I didn't refer to the S2 at all.. Just comparing general photo quality between 2 different 3mp cameras and a 1mp.. for an additional comparison.

My point is... (like YOU just mentioned as well).. You can't choose a camera on Mp at all.. You need to look at additional aspects of a camera (ie: sesors, etc)..

In my opinion.. My phone (at 1mp) takes a better pic than the cheapie that my mom picked up for 50.00 that has 3mp.... Then again my SONY (not S2) takes better pics yet than the camera in the same mp catagory as the cheapie.


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Old Feb 5, 2006, 2:32 PM   #10
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Bart150 wrote:
Quote:
  • In general, other things being equal, the more megapixels a digital camera has, the HIGHER the quality of the image - provided the camera is not used at ISO400 or higher.[/*]
  • But when used at ISO400 or higher, in general, other things being equal, the more megapixels a digital camera has, the LOWER the quality of the image.[/*]
1. That's because it can capture more/smaller details

2. More megapixels means size of pixel and its light gathering area is smaller which causes lower signal/voltage (requiring more amplification)... all this while heat noise is amplified equally much more which leads to worser signal-noise ratio.


PS. while text formatting with font/size controls is there using it without some meaning ain't sensible... it makes shortening quotes very hard.

vwmom wrote:
Quote:
Right now I think R&D feels that people want MORE PIXELS..
Propably not them, from their perspective it makes work much harder because small sensors with way too much pixels start to cause some noise even at lowest ISOs so I think right target for positively hard kick to rear-feedback is BS departments with their marketing clowns!
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