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Old Jun 3, 2004, 8:47 AM   #21
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The reason I proposed the question in the first place was for a very simple reason. All the research I have done suggests that scientific research shows that anything over 5 or 6 MP's is only a loss of quality by adding more noise. I just purchased an Olympus C-8080 and was trying to understand where to dial it in within the 5-6MP range for optimum resolution and image quality.
You don't reduce the noise by dialing in a lower Mp on a high Mp camera from everything I've read. The noise is in the sensor regardless of how you have the camera downsample the pixels.

I don't agree that everything over 5-6Mp is only a loss of quality. People have been saying that since 1Mp, but the technology seems to be improving. It of course isn't true of an 8Mp DSLR and I've been pleasantly surprised by the images from the current crop of 8Mp prosumer cameras like yours. If you display an image from a good 5Mp and an 8Mp camera at the same size or print them at the same size the noise is about the same. It is when you view it 100% that you see the higher noise, and that is sort of like blowing it up to see the noise. There are programs that will deal with the noise quite nicely if you want to do a large print, but nothing you can do about not having enough pixels.

If you are in a situation where you want good pictures but feel you will need to put more on the card than will fit at best quality and full resolution, I personally prefer dropping a notch in quality and keeping the resolution.

If you use 2X digital zoom on your 8Mp camera you will end up with a 2Mp image. Most cameras resample it back up to 8Mp, but you still have only 2Mp of image information. There has been a lot of discussion where people who take the trouble to do comparative tests find the digital zoom is better than taking the full picture and cropping it. They say the reason is that the camera is doing the resample before the JPG conversion. I don't have an opinion on that other than that the difference is small.
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Old Jun 7, 2004, 11:48 PM   #22
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Thanks Slipe, Good information. Thanks again.

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Old Jun 8, 2004, 8:41 PM   #23
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slipe wrote:
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You don't reduce the noise by dialing in a lower Mp on a high Mp camera from everything I've read. The noise is in the sensor regardless of how you have the camera downsample the pixels.
Depends on how the camera does the downsizing. True, the noise is in the sensor, however downsizing by "averaging" adjacent pixels will reduce noise at the same time it reduces resolution. Some cameras (Minolta?) take advatage of this and the tight releationship between noise level and ISO to increase the ISO by limiting the resolution of the shots at high resolution.

Using PhotoShop's bicubic downsizing does reduce noise close to the expected square root of the ratio of before/after pixel count. Easy to do the test - shoot a gray card at the highest ISO your camera allows. Look at the std dev (found under image-histogram). Downsize and check the std dev again. It will not be exactly the square root of the ratio since it is almost impossible to uniformly light a gray card, but it will be close.
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Old Jun 9, 2004, 1:54 AM   #24
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BillDrew is right. Its called binning. A block of sensor elements are used to form a pixel. Reduces noise (and the intended resolution of course).
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Old Jun 9, 2004, 11:35 PM   #25
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BillDrew is right. Its called binning. A block of sensor elements are used to form a pixel. Reduces noise (and the intended resolution of course).

Hey Jurgen,

Great to see you on the forum! I didn't realize you were back in Germany -

For those who haven't had the pleasure, please visit Jurgen's site and have a look at his incredible program "cPicture" - in my opinion it's one of the very best utilities for doing lots of things including creating quick and extremely clean web code for displaying your images.

Best regards,

Lin

Here's a link:

http://cpicture.de/en/index.html


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Old Jun 10, 2004, 3:08 AM   #26
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Hi Lin,

now this is a nice surprise!
Good to see the real professionals here. I'm only a software engineer

You should post your expertise on panoramas! I saw your work on Max Lyonsforum. Very impressive how you dealed with this complicated contrasts of your work like: http://www.lin-evans.com/photos/cliffpalace.jpg!

Not sure if I'm back to Germany There are quite some lines of code made in 33000 ft above the ground. I'm in close touch with the inventor of the lossless JPEG rotate (he is also from Germany), so its all very exciting!

Regards
J├╝rgen

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