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Old Dec 13, 2007, 10:29 AM   #1
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I have read that new cameras tend to not perform as well as their older siblings because they are trying to cram too many pixels on small sensors. Does lowering the image quality settings reduce the noise?
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Old Dec 13, 2007, 10:44 AM   #2
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The only thing lowering the image quality does is reduce the maximum size you can print and allows you to store more images on a card. Noise characteristics will be the same whether you shoot the image at full, half or quarter-resolution.

People ask this question all the time, but it makes no sense if you thing about it. All that happens when you shoot at a lower resolution is the camera is using a smaller portion of the image sensor. The number of pixels over the area useddoes not change, so there is no change in what noise you'll see at any resolution. If youcombine smaller resolution withhigher compression levelsyou actually make image quality WORSE.

If image quality is important to you, there no excuse to shoot at anything other than the highest quality/resolution.

Newer cameras perform better than older ones.Some use smaller pixels, but the processing is more advanced and faster. I've seen few instances where I would prefer to use a camera two or more generations removed from the current model.

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Old Dec 13, 2007, 11:10 AM   #3
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richwolf wrote:
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I have read that new cameras tend to not perform as well as their older siblings because they are trying to cram too many pixels on small sensors.
What you have read is just one aspect of what happens in newer digicams that doesn't happen in older ones.

When manufacturers make higher resolution image sensors, the density of the pixels increases (that is, there are more light sensors packed more closely together.) Also, newer image sensors are capable of being more sensitive to light than older image sensors. When you do both of these simultaneously, that is, you pack the pixels closer together and you make them more sensitive, any individualpixel is more likely to be influenced by the light detected by its neighbors, and may respond at a level out of proportion to the actual amount of light received throught the lens. This is called 'Noise', an dis the effect you've no doubt been reading about.

This is most severe in digicams with small, higher resolutionimage sensors when the digicam is set at a high sensitivity setting (large ISO values.) At more conventional ISO values, a higher resolution image sensor produces higher quality images than a lower resolution image sensor. And in all other respects, a higher resolution image sensor will always produce higher quality images than a lower resolution image sensor.

So, increasing the sensitiviy of the image sensor (increasing the ISO setting) beyond that available to older digicams allows someone to take properly exposed photos in less light than was possible with earlier digicams, though with the unfortunate, inevitable consequence of noise.

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Does lowering the image quality settings reduce the noise?
Reducing the resolution of the image sensor doesn't actually reduce the incidence of noise, it just averages it out. Unfortunately, it also averages out the detail in the rest of the photo as well.
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Old Dec 13, 2007, 12:43 PM   #4
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Thanks for the responses!

I am sorry if this has been asked before, but in reading some reviews it seems like they say older cameras had less noise than their newer counterparts have.

You explanations make sense. So I guess I will stay at maximum image quality.
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Old Dec 13, 2007, 3:16 PM   #5
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richwolf wrote:
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... So I guess I will stay at maximum image quality.
Have you been experiencing a lot of noise with a new digicam?

From your original question, I was presuming that the question was academic. From this comment, it seems that I was wrong, and that you actually have a practical reason for asking the question.
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Old Dec 13, 2007, 3:58 PM   #6
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No the question was more academic based upon reviews that I have been reading about "cramming" more megapixels onto a small sensor.

Overall I am happy with my new camera ( a Pansonice FZ8) but since it is new to me I have been researching using different settings from IQ to ISO to metering and using the manual controls.

A DSLR would be nice but the one I want with 2 lenses would have run about5 times as much.

This is quite a step up from my Canon digital elph so it will keep me happy for a while.
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Old Dec 14, 2007, 8:23 AM   #7
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TCav wrote:
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.... Reducing the resolution of the image sensor doesn't actually reduce the incidence of noise, it just averages it out. Unfortunately, it also averages out the detail in the rest of the photo as well.
Averaging is one standard way to reduce noise. The effect can be seen by shooting a photo of a uniformly lit, monochrome wall/piece of paper/sky/... If it were truly uniformly lit and monochrome with no noise the histogram would be a delta function, i.e., have a zero value everywhere but one place. Since this is a photo of a real object and there will always be some noise, the histogram will have some width - usually the standard deviation is used as a measure of that width. That width will be a combination of noise and the real lack of uniform lighting and monochonicity.

To maximize the noise component, shoot at the highest ISO poossible in the dimmest light possible.

Downsize that image and look at the histogram again. It will be narrower. That means it has less noise. I would expect the SD to decrease by the square root of the ratio of the after/before pixel count.

As TCav points out, downsizing also decreases the detail in the image so the whole issue of decreasing noise by downsizing is somewhat academic.

However, averaging several images to reduce noise works well. See Max Lyon's examples of synthetic long exposures as the best examples I know of. http://www.tawbaware.com/maxlyons/cg...e.pl?gallery=8
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