Digital Cameras: What megapixels & zooms mean?

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There are some big myths out there about digital cameras. No two are bigger than sensor size (megapixel) and optical &  digital zoom. In this guide I will attempt to clarify these two important features when buying a digital camera.

First of all let’s clarify what megapixels actually mean. This is a term given to describe the maximum resolution possible from a digital camera from its sensor. This term megapixel does not mean that the bigger the megapixel the better the photographic quality, it does not mean that at all, there are two other things that determine the picture quality, and I will mention those down below in more detail. Back to resolution: If you have a 2 megapixel digital camera, that means that photograph has enough resolution to be enlarged upto 6x8inches, any enlargement bigger than these are you will be stretching the photograph beyond its limit and reducing the image quality. Conversely a 3 megapixel camera can produce a file of a high enough resolution to make enlargements on paper up to 8x10inches in size. Cameras with a larger megapixels than 3 can producer larger photographs than A4 in size.

What does determine the image quality from a digital camera is that quality of the lens and the quality of the sensor that produces the photographs from that camera. This can not be determined from just looking at a digital camera box. Reviews need to be found to determine this and speak to experienced photographers, but no doubt that well established camera brands will offer higher quality in these two areas than no-name brand cameras.

Secondly let’s cover digital and optical zoom. Optical zoom is what we should be looking at when buying a digital camera as digital zoom is inferior. Optical zoom as the name suggests uses the glass optics of a lens to zoom in and out of a scene. Digital zoom is employed after the optical zoom is used to its full extent. Digital zoom uses software inside the camera to keep zooming in on a scene after the optical glass inside your camera has gone to its limit. Digital zoom does degrade the photographs image quality to some degree, depending upon which model of camera and how much is used in the photo. My recommendation is to buy a camera on the strength of its optical zoom and not digital zoom. A better option to zoom further into a photograph than digital zoom is to use a photo editing program on your computer after the photograph is taken to crop the photograph. This cropping will offer better quality than using digital zoom.

When looking at optical zoom, you will see numbers stated as: x3, x4, x6, x12 etc This numbers refer to the magnification ratio of that particular camera.  The best thing to do is to try these cameras out, zoom in and out and see what ration of magnification you need for your purposes and budget. A x3 optical zoom is standard and you will see in entry-range digital camera. This zoom ratio is suitable for general picture taking, family, portraits etc and allows the camera to be compact. Your larger optical zoom cameras of x10 or x12 offer greater magnification especially for sports or wildlife photography where it is hard to get near to your subject. The disadvantage in buying a camera with a larger optical zoom capability is the camera is generally larger in size and is like looking through a pair of binoculars; (the scene when viewed with a x10 or x12 times zoom can be hard to keep still), so a tripod or a camera that has image-stabiliser is a must.

An image stabiliser is technology built into the lens to compensate for camera shake or the natural hand movement, so we can take sharper photographs. This is of particular use when using cameras with an optical zoom of longer than x6. Various camera brands off this and Panasonic build it into every camera they produce.

In conclusion we can see that the sensor is the device in a digital camera that replaces film and as such, needs to be of a high quality, as well as the lens of a digital camera. The megapixel number is not going to determine the quality of the photographs produced from that camera, but give a guide to the size of the photographs for enlargement purposes. Reviews are needed to make a judgment of this or look at sample photographs. www.stevesdigicams.com  is one of the best. The optical zoom is a far more important feature to look at when buying a digital camera than digital zoom, due to its degrading characteristics.

 
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