Digital Camera Help - FAQs

By Mel McGee

Here are some of the most frequently asked questions that I have answered from visitors to my Digital-Camera-Help.com website.

What is the difference between optical and digital zoom?

Optical zoom on a digital camera works the same way a regular 35mm camera's zoom works, the lens physically moves in and out using the optics (lens) to bring the subject closer without sacrificing quality. These moving lenses allows a range in optical magnification that runs anywhere from 2.0x to 10.0x. The higher the optical zoom on a camera, the farther away you can be to take a photograph and still get a clear, close image.

Digital zoom is a software simulation of optical zoom using no moving parts. Simply put, the camera crops the picture and enlarges it, filling in the extra pixels by guessing what the picture may look like in a process called interpolation. This results in a loss of quality, and is no different than cropping and enlarging an image with editing software. Instead of using the digital zoom on your digital camera you can use editing software on your computer and have more control over cropping and enlarging the picture.

Many new models of digital cameras are advertising having both optical and digital zoom capabilities. Most of these cameras have a feature that automatically uses digital zoom when you have exceeded the optical zoom limitations. You may choose to disable or shut this feature off so that you know exactly what kind of quality picture you are taking.

How much zoom does your digital camera need?

Optical zoom ranges between 2x and 10x but most average users find 3x to 6x optical zoom about what they need. Most experts will tell you to buy as much optical zoom as you can afford being careful not to overlook the other features.

What is megapixel?

Ok, first let's define pixel. Digital images like our computer screens and digital camera pictures are both made up of grids of dots. The word "pixel" is actually short for "picture element", which is computer geek talk for one of those millions of dots on your computer screen or digital image. Now, every one of those pixels holds one color and combined with the other millions of single colored dots, forms the picture.

Megapixel means a million pixels, so a 3 megapixel digital camera has 3 million pixels. To get the total pixel count, you multiply the horizontal pixels by the vertical pixels. For example, 2590 x 1920 = 5 Megapixels. The more mega pixels your digital camera has, the more information and detail you capture on each picture.

Say for example, you a take a picture, once with a 2 megapixel digital camera and once again with a 4 megapixel digital camera. The 2 megapixel digital camera will give you 2 million pieces of information (pixels) and the 4 megapixel digital camera gives you 4 million pieces of information (pixels). If you print both the pictures 4x6, you probably would not be able to tell the difference between the two. Now say you were to crop the pictures or enlarge those pictures to 8x10, you would see a big difference in the two photos. The picture taken by the 4 megapixel digital camera would be a clearer, truer image replication because the picture contains more information than the 2 megapixel digital camera.

How many megapixels does my digital camera need?

It mostly depends on what you plan on doing with the pictures and images. If you do not often crop your photos and only print 4x6/5x7 size photos, a 2-3 megapixel digital camera will do the trick. If you ever plan to make 8x10 or larger prints at least 4 megapixels would be suggested. Of course most would tell you to buy the highest megapixel digital camera you could afford, but the smart ones would also remind you there are a lot of other of other features besides megapixel you want to look at when making your digital camera purchase.

What is the difference between a Nickel-Metal Hydride battery and a nickel-cadmium battery?

A Nickel-Metal Hydride battery (or NiMH) is a rechargeable battery similar in design with a Nickel-Cadmium battery (or Ni-Cd) but instead of using cadmium, which is an environmental hazard, it uses a hydrogen absorbing alloy for anode. A Nickel-Metal Hydride battery can have 2 to 3 times the capacity of an equivalent size NiCd, the memory effect is not as significant and it is less detrimental to the environment compared to a Nickel-Cadmium battery.