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Old Oct 2, 2006, 9:11 AM   #1
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I own a Canon s2is and get good results . I was thinking about getting an s4is when they come out this Spring . A friend tells me that a 7 or 8 mp won't make much difference because of the sensor size . Would someone shed some light on this issue .


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Old Oct 2, 2006, 4:17 PM   #2
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Best to read the reviews when the new cameras are released. Packing more Mp onto the same size sensor can cause more noise and lower quality results.

Also depending on what you do with your pictures you may not see any improvement. A computer monitor is <1Mp and with prints the number of Mp needed depends on the final size. With 5Mp your present camera is capable of good A4 prints that 7 or 8 Mp probably won't improve on.

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Old Oct 6, 2006, 7:52 AM   #3
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I agree with Nagasaki's comments. Moving from 5mp to 7-8mp will not make a noticeable difference in quality. That is only a small difference in pixel count (like 20%), you would have to go from 5 to 20 mp to double your resolution. However as they put more pixels into the same size sensor, the camera's tend to be more noisy. So you might find that your old cam would probalby give slightly better images than the new model (of course they might pull off a miracle, only time will tell). However there might be other reasons you would want to upgrade, like larger LCD, etc. But not for image quality.If you really want a noticeable increase in image quality you need to go to a true DSLR which has a much larger sensor. But again you probably could only tell if you really pushed it.*
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Old Oct 6, 2006, 9:20 AM   #4
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Megapixels is an obscure measurement that dosent tell anybody anything useful.

There are too many obscure detailed differences between cameras to make solid generalizations, its best to compare one directly to the other by images (in your prefered output format, either resized for web or printed). Optical design, quantum physics, software design.... extremely complex fields that work together in interesting ways to record your images.

Many of the complications and limitations are excaberated when you make pixels smaller (higher megapixel count), but thats never the whole story either. Color, contrast, and dynamic range can have huge effect on the image too but are never touched on in these kinds of discussions.

Its true, for many reasons, that DSLR's give the best image quality. Its also true that a Ferrari gives the best driving performance but that dosent make it a good commuter car either.

Its all relative.
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Old Oct 6, 2006, 9:51 AM   #5
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Good points all. But before we get sidetracked on another MP discussion, is it safe to assume everyone agrees that a megapixel increase alone (given what the mp increase is likely to be) is a poor reason to upgrade. It's the other features of the camera that will likely be of more interest:

Will have Digic III chip

Might have facial recognition

Might have better noise performance

Might have even better movie mode (already a strong suit).

Lot's of other 'might haves' - I don't mean to start a speculation thread. Only pointing out that a replacement may or may not have other significant improvements - but at this point MP alone isn't a very useful improvement.
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Old Oct 6, 2006, 10:09 AM   #6
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Unless you plan on printing at larger sizes or cropping a lot (and you can't crop as much as you think and maintain acceptable quality), then the MP war is just that.

Unfortunately, most consumers seem to think that more megaixels = higher mage quality. But, that's not necessarily the case. Sometimes the opposite can be true.

So, you really need to take each model on a case by case basis. You'll also find some sample images from the models Steve has reviewed here (last page in each review contains sample images).

So, you can test how well they print at different sizes for yourself if you download them. Just make sure you're looking at images taken in the same conditions you plan on using a camera in.

Most models do OK in good light. But, when you need to crank up the ISO speed in less than optimum lighting, image quality can degrade significantly.

Even a 2 Megapixel camera can make acceptable quality prints at under 8x10" sizes for many subjects (i.e, portraits), if it's a decent camera (lens, image processing algorithms, etc.). 3 Megapixels is noticeably better at around 8x10" from most cameras

After that, at typical viewing distances for prints 8x10" or smaller, you begin to see diminishing returns going to higher resolution images, looking at the output from most inkjet printers, based on my experience printing at that size.

But, again, you really need to take models you consider on a case by case basis. Megapixel count alone is not enough to judge how well a camera is going to perform. There are too many other factors (lens quality, metering reliability, autofocus accuracy, color accuracy, dynamic range, noise, the quality of the in camera image processing and more).

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Old Oct 6, 2006, 7:57 PM   #7
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Being a contrarien, I'd suggest ignoring image comparisons when deciding between cameras - at least ignore them beyond the point of noting that one is just plain bad.

It is pretty much impossible to set two different cameras to the same settings - contrast, saturation, brightness, white balance, gama, ... Differences in those settings are likely to cause as much change for camera A than there is difference between camara A and camera B. Some camera's defaults are set to produce more ZING (technical term - those are the settings thatsell cameras) while others have their defaults set to more modest values, allowing the user more control over their image.

So if you want a camera that you can "grow into", and you don't mind figuring out how to use some silly menu - pretty much ignore image comparisons. Just about any camera being sold will produce good images.
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Old Oct 8, 2006, 8:20 AM   #8
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Don't forget the quality of the lens and the manufacturing tolerances that go into achieving a proper focus.

I bought a 6 MP camera (a Canon SD700/Ixus800) and ata few, fortunately not all,settings there is some corner blur whichmeans the lens limitations are showing up.

(Test results I gotare posted in the Canon section of this forum ca. 7/20/06)http://www.stevesforums.com/forums/v...mp;forum_id=15

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Old Oct 10, 2006, 9:47 AM   #9
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My current camera is 3.1 Mpixels. Even the 6x8 prints look great. I know that I'm never going to print anything bigger.

The biggest point for buying more megapixels is being able to get good prints when you have to crop most of the image out.

Unless you are making huge prints, of course...
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Old Oct 10, 2006, 11:32 AM   #10
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digraph wrote:
The biggest point for buying more megapixels is being able to get good prints when you have to crop most of the image out.
You can't crop as much as you think and maintain acceptable quality.

If you crop an image to make it look like twice as much optical zoom was used, you end up with 1/4 (not 1/2) the original resolution (because resolution, like area, is computed by multiplying width x height).

So, if you really need to pull in subjects closer, there is no substitute for Optical Zoom.

You can see a table comparing the resolving power of some of the popular "long zoom" models here (watch out for the popup advertisements). This table does not take other characteristics of a camera into consideration (lens quality, etc.). It's just designed to show you that even a lower resolution camera can pull in more detail compared to cropping an image from a higher resolution model with less optical zoom.


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