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hoobygroovy Aug 9, 2004 10:27 AM

I have read a reply to a posting in another section stating that more megapixels can actually give you a poorer quality image in the size of the CCD is not increased.

To what extent does more pixels lower the image quality? For example, would the Canon S410 produce better pictures than the S500, or the Casio EX-Z30 produce better pictures than the EX-Z40?

Are there any guidelines for megapixel to CCD size ratio?

Chako Aug 10, 2004 7:33 AM

Many 8 megapixel cameras are proving to be poor low light performers, showing excessive noise at200 ISO and above. They tend to work best at ISO 50-100. Mind you, this varies with model to model.

Anyhow, here is some info I found on the subject matter that should help you a little in this regard. My apologies for posting a link to one of Steve's competitors, and hope he doesn't mind.

slipe Aug 10, 2004 9:21 AM

It is hard to answer whether a S410 will produce a better image than a S500. At a given ISO the 410 will have a little less noise. But it has less pixel density if you need the pixels.

If you view them both at the same size there won't be a lot of difference except at higher ISO. If you view them 100% you will see more noise in the S500 shot.

Noise can be reduced with several good programs available but you can't increase information that isn't there. If you want to print a 13 X 19 the end result will be better with the S500.

You can get to the point where noise actually reduces the image information. Using Neat Image or Noise Ninja can't recover that lost information any more than an upsample of a smaller image increases information content. But you get to that point almost as fast with the 410. Both cameras have a high density and aren't great for noise and dynamic range.

I would personally go for the S500. I have a wide format photo printer and running an image through Neat Image is a small step in printing a wide format print. Optical viewfinders don't show the whole image like the LCD, so you are losing 10-20% just in cropping if you frame with the optical finder. If you are able to use the entire 5Mp image you end up with about 135 PPI for a 13 X 19, which is marginal.

The CCD and camera manufacturers seem to be doing something. When they went to the first small 3Mp cameras there were people screaming that the noise had become unacceptable and any further density increase would mean the end of the world as we know it. They have increased the density considerably and the images are still acceptable. Viewed at 100% the noise is certainly there, and an 8Mp image from a good prosumer camera isn't as good as a 6Mp DSLR image IMO. Viewed at screen size or printed they look OK. And if you want to make a large print it isn't that big a deal to run them through Neat Image.

If you want something tiny to carry in your pocket you will have a tiny sensor. If you want to print larger than snapshot size you will get noise – especially in lower light. They already have tiny 6Mp sensors and Pentax is about to come out with a 7Mp version of their 555 – tiny sensor of course. If you want a pocket camera with a 3-5X optical zoom and decent pixels for large prints you will have to deal with noise. Look at Steve's sample photos and decide whether the images are acceptable.

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