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Old Jan 14, 2007, 2:04 PM   #1
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I want to buy a nice camera, but I want to make sure its got the right amount of mega pixels.

The one I like the most has 7 mega pixels. Recently its competitors (which I find more difficult to use) jumped from 8 mega pixels to 10-12 megfa pixels. The lenses (interchangeable) on all cameras are good. However a salesman was telling me that mega pixels are not a big factor if the lense is great. I don't believe that.

I have noticed that in this digital photography forum there has not been much emphasis placed on mega pixels and wondered if someone could tell me at what point doesn't megapixels matter anymore.
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Old Jan 14, 2007, 3:01 PM   #2
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At 7MP and above, the differences usually only become apparent if you enlarge photos for large prints. If you're going to be shooting for the web or aren't going to do large prints, you probably won't notice too much of a difference between 7MP and 10MP without taking a hard look.

MP aren't everything. You need to consider how a photo gets rendered by the camera's processing. A 10MP camera could actually take photos that appear softer than a 7MP camera, all due to the photo processing done by the camera.
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Old Jan 14, 2007, 3:34 PM   #3
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I have a 3.2MP and it takes good 5x7 and great 4x6 photos, what's great about more MP is that you can crop your shots without losing info for those small sizes. But don't get inferior glass in favor of MP.
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Old Jan 14, 2007, 3:37 PM   #4
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I agree with Illuminati that megapixel count isn't the be all and end all in digital cameras. The quality of the pixels is more significant than the quantity. If 7mp results in overly small photosites on the sensor then you will have noisy images and poor quality. Check the reviews on Steve's Digicams and other review sites and see what they say about image noise at all ISO settings.

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Old Jan 14, 2007, 4:57 PM   #5
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What's important, too is lens quality. I'd rather have 5 MP with great glass than 10MP with inferior glass.


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Old Jan 14, 2007, 6:40 PM   #6
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I also agree with everyone that megapixel count is not everything - the quality of the digital picture is a product of:

lens quality,
pixel count,
sensor (CCD) quality,
the camera's built-in software/ algorithm to create a picture from the sensor information,
the amount of digital compression (eg. "Fine", "Normal" quality settings for JPEG)

Then it depends on what method you choose to view the digital pictures:

if you view them digitally - the quality (resolution (PPI - see later), color, contrast etc.) of your PC monitor or TV (high definition, plasma, LCD ...);

f you view them on prints - the quality of your printer (which is affected by the printing resolution (pixels per inches count or PPI setting), printer's designed printing quality, and print paper quality.

If you are making small prints such as usual 4 X 6s, a 5 MP camera is more than adequate. Read this guide about the relation between pixel count and print size:

http://www.microsoft.com/windowsxp/u...stquality.mspx

Note that you may get away with a low(er) PPI - (1) if your prints are small like 4 X 6 (2) if you prints are large but people are not going to view them close-up, so detail is not as important.

The only situation in which a high megapixel camera has advantage is that, you can crop (select only a portion) of the picture and make decent sized prints out of them ("cropping" using photo software is similar to the "digital zoom" function of the camera).
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Old Jan 14, 2007, 7:59 PM   #7
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One more factor to consider is that the more megapixels that are put onto a sensor, the darker the pictures tend to be. For example, the Pentax K10 is a 10mp camera that is the upgraded version of the K100d, which is a 6mp camera. The K100d is nearly twice as bright, meaning it needs about half as much light to get the same exposure as the K10. This means the K100d can take better quality pictures indoors without a flash than the much more expensive K10. The K10 however can be a more desirable camera for taking photos outdoors and in brighter light as it will capture more detail with those extra pixels, allowing for bigger enlargements or tighter crops.
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Old Jan 14, 2007, 10:25 PM   #8
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Corpsy wrote:
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One more factor to consider is that the more megapixels that are put onto a sensor, the darker the pictures tend to be. For example, the Pentax K10 is a 10mp camera that is the upgraded version of the K100d, which is a 6mp camera. The K100d is nearly twice as bright, meaning it needs about half as much light to get the same exposure as the K10. This means the K100d can take better quality pictures indoors without a flash than the much more expensive K10. The K10 however can be a more desirable camera for taking photos outdoors and in brighter light as it will capture more detail with those extra pixels, allowing for bigger enlargements or tighter crops.
I don't think that is true. Dpreview measured the ISO to be dead on in the K10 review. And the sensors on the K100 and K10 are the same size. With the same lens and settings it should deliver the same exposure. The K10 is lacking a little in highlight dynamic range, but that is a different thing. Probably a combination of sensor density and sensor design – it isn't the commonly used Sony sensor according to dpreview.

It isn't generally true that increasing the density decreases the light sensitivity. If you look at cameras with non-interchangeable lenses they keep the same light sensitivity with higher capacity sensors if they don't change the sensor size or lens.




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Old Jan 15, 2007, 4:50 AM   #9
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Slipe, I probably should have been a bit more specific. While two cameras with different resolutions may obtain the same exposures using the same settings, the higher megapixel camera will tend to have higher noise, making it less effective in low light.

Here's a thread where the two cameras are compared at high ISO:
http://www.stevesforums.com/forums/v...mp;forum_id=80
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Old Jan 22, 2007, 1:55 PM   #10
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Let's begin with the basics. Photographers make pictures, not cameras. Great pictures are made by photographers that use the tools at hand effectively for the results intended.

That said we do have to look at the intended purpose. If the pictures are to be viewed on a computer screen at a 1024x768 and the photographer has done the things required (framed correctly by using optical zoom/foot zoom, held/supported/useda fast enough shutter speed to eliminate motion blur) and the lens itself is sharp then .8 mp is all that's required. 2 mp will deliver a fine 8x10, again if the photographer has paid attention to the factors above. 4 mp can do 20x30 and 6 mp will do 30x40.

A historical note - the first all digital issue of National Geographic used 5 mp sensors, these where essentially digital backs on Nikon (and maybe Olympus 35s). Their basic quality standard was Nikon and Olympus cameras/lenses using Kodachrome 25 film.

Once one goes beyond the mp's above those extra mp's do allows one to at least partially compensate for errors made during the picture taking process. In some cases it may also allow for higher ISO's without noise intruding on the final picture which then allows greater freedom to use shutter/aperture controls to the best photographic effect.

I would definitely select a 7 mp with a great lens over a 10 mp with a so-so lens. I likely would select a 7 mp good controls over a 10 mp with poor controls simply because having good controls would let me focus on the job at hand, taking good pictures.

You might find it instructive to compare the pictures in Steve's review of the Kodak Z612 and P712, especially the Presidential seal picture. In this case 6 mp's beat 7 mp's.

AC
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