Saturday, November 3, 2007

The Megapixel Myth--And What Really Matters

Today, we will look at the digital camera megapixel, some misconceptions, and what factors affect it's performance. First off...

Some Common Misconceptions

People generally think the more megapixels a camera has the better it is. With the advancements in noise reduction, this might seem to be the case. But the number of megapixels is not the main factor behind the level of detail and the dynamic range (the ability of the sensor to capture the dark and light parts of a picture—a sensor with better dynamic range will be able to record more information in the shadows and the highlights (the bright parts) of the scene). The dynamic range and the level of detail are also affected by the size of the pixel.


Pixel Size?

Yes, the size of the pixel makes a difference. The larger the pixel, the more information it can record. Thus, a digital SLR pixel will record more detail than a pixel in a compact digital camera (because it has larger pixels). In addition, the dynamic range of a photo taken by a digital SLR will be better than that of a compact and in terms of detail, a 6-megapixel dSLR will have about the same amount as a 10-megapixel digital compact. The size of the pixels (and of the sensor) is the main difference between the digital SLR and the digital compact and the one of the factors distinguishing between them.

6-megapixels vs. 10-megapixels

What? Isn't that unfair? A 10-megapixel camera clearly has more megapixels and and it follows that it would be a better camera. The answer is: not necessarily. The more megapixels you squeeze into a camera, the more "noise" there will be in a picture. Noise appears as blue/purple/reddish spots in the pictures. A camera with more megapixels tends to have more noise than one with fewer megapixels. As you go up in ISO (sensor sensitivity), the noise difference between a 10-megapixel camera with the same sensor size as a 6-megapixel camera will increase; the 10-megapixel one will be much noisier. This is the tradeoff for more megapixels in a camera. However, noise reduction technology is improving greatly, so this difference is becoming almost negligible.

Why not just make all sensors bigger?

Because it costs a lot more to produce a camera with a larger sensor. The main reason a digital SLR costs more than a digital compact is this.

How does this affect me?

What type of camera you wish to purchase depends on your needs. If you are seeking to become more serious about photography or you want more detail and sharpness in your photos, you should buy a digital SLR. If you only want a camera to record family memories or just for casual shooting, you should purchase a compact. In the latter case, because you probably won't be making prints larger than 8"x10", it is recommended you purchase one with 10+ megapixels. All your functions you need would easily be met and the number of megapixels would be just about right for the outputs. On the other hand, if you are truly interested in photography, you should look into purchasing a digital SLR; the flexibility of a digital SLR and the quality of the photos would offset the price.


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If you have any questions or comments, feel free to let me know, and happy shooting!

1 comment:

James said...

Hey Joseph, this is great. There is a ton to say about this subject. Thanks for the info though. I'd like to see more added to the site. Keep it up!