Digital photography

What you need to know about megapixels

Few people knew what a megapixel was until the digital camera explosion of the past few years.
Now it's one of the most common phrases used to describe a camera and is a measurement standard to compare models.
Often the most confusing question is how many megapixels are needed?
Megapixels are a standard of resolution in digital cameras used to measure image quality.
A megapixel is a million pixels and the more pixels in the camera, the better the quality of photos. But there are other factors that affect the quality -- lens type, image processor, etc.
In many cases, bigger is not better.
Opinions differ on how many megapixels are needed for different sized prints. Some basic guidelines: 5 megapixels for 8x10 prints, 3 megapixels for 5x7 prints and 2 megapixels for 4x6 prints.
These numbers can vary among users, camera dealers and the manufacturers, but should get you in the ballpark.
Many claim the same print quality can be produced by cameras with different numbers of megapixels.
So I had an 8x10 print made from cameras with a megapixel rating of 2, 5, 6 and 7.
After showing the prints to a few professional photographers, the photographers agreed there is not much difference with cameras over 5 megapixels.
Most amateur photographers won't see a difference in their images with a 6-megapixel camera versus an 8-megapixel camera. But there can be a big price difference.
In addition to camera cost, higher megapixel cameras also require more space on the memory cards and allow fewer images per card. The result: more cards and more cost.
Most current digital cameras include an option to change the image quality. Lowering the quality allows for more images on the existing media card. The exact number depends on the camera and the size of the card.
When this setting is turned down, the camera does not use all the pixels available.
Instead, several smaller ones combine to make a bigger one.
Unless there is a specific reason to turn down the resolution, users should leave this set for the highest quality possible.
Many users will only be taking photos for e-mail or Web site purposes. In that case, the image setting could be lowered since higher quality is not needed for the Internet.