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Digital Camera ResolutionHow Many Pixels Do I Need?If you listen to the marketing hype, the higher your digital camera resolution the better, right? Not always. With technology changing so fast, camera manufacturers are in a race for the most megapixels. But packing more pixels into a camera is not always better. Let me explain why. Sensor DesignEach pixel that is on the camera's sensor is actually at the bottom of a 'pixel well'. At the top of each well is a lens that focuses the light onto the pixel. As they pack more and more pixels onto the sensor, the pixels get smaller and less sensitive to light. They have to amplify, or turn up the volume, of each pixel in order to get an image from the fainter light. This causes noise which looks a bit like grain in the old higher ISO films.
Special software built into the camera reduces the noise to an acceptable level. This is a bit of a trade off though. To reduce the noise, they have to 'blur' it out of the photo. The quality of your photo depends a whole lot on how aggressive the camera manufacturer is with it's noise reduction. Some companies use a lot, which when enlarged makes the photo look like a painting, and some don't use much, forcing you to do it afterwards. Choosing which is best is more personal taste than anything. Sensor SizeNot many cameras have a sensor that is the same size as 35mm film. Most are quite a bit smaller, and size does matter on digital cameras. In the chart below you can see the sizes of sensors in many digital cameras these days compared to 35mm film or 'full frame' sensors.
Sensor Size Vs MegapixelsImagine you have 10 million pixels (megapixels) on a full frame sensor. Each pixel would be quite large and be very sensitive to light.Now imagine one of the smaller APS-C sensors with 10 megapixels. Each pixel would have to be a lot smaller making them less sensitive to light. Which means more noise reduction. How Many Pixels Do I Need (again)?You can see how it is a trade off between sensor size and megapixels. As software and sensor technology gets better, noise will become less of a problem. Many people will not even notice the difference. But if you are a 'pixel peeper', a good rule of thumb is bigger pixels = less noise = better photos.If you really pressed me for an opinion I would tell you that, with todays technology (Summer 07), I would choose a digital camera resolution of 6 megapixels for a point and shoot and 8 megapixels for an APS-C sized sensor. Ha! But I just bought 2 10 megapixel Canon 40D's with APS-C sensors. Sometimes technology just doesn't give you the choice. Happy Shooting! Return to Best Digital Photography Tips
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