Computer Big Lab

Digital Camera Resolution (Amount of Pixels) (MegaPixels)

Digital cameras are advertised as having a certain resolution (amount of pixels or MegaPixels), this directly relates to the quality of the photos that can be taken and then printed.

 

The higher the amount of pixels a camera supports, the sharper the image. If you intend to enlarge your photos, rather than just look at them on your PC, then you will want a camera with a higher resolution. Digital camera resolutions start off at around 1 million pixels (1 MegaPixel), and reach 7 million or higher.

A lot of digital cameras allow you to change the resolution before taking pictures. The smallest resolution settings are around 640x480 or 1024x768 pixels. As larger resolution photos take up more space (and more battery power when storing) it can be advantageous to be able to select the resolution yourself.

If you think you may want to enlarge your photos (large prints), then before you take your pictures, check that the camera is at a high resolution setting.

Below is a rough guide to the relationship between resolution and print size.

File compression

This refers to the way in which the camera stores the image.

On most digital cameras there are 3 compression settings. The setting you choose will depend on what you want to do with the image. If you want to enlarge the images and have them printed, then choose the lowest level of compression (sometimes called fine or high quality, file type: TIFF ).

If you don't want to enlarge the photos to more than an average photo size, then choose the medium compression setting (sometimes called normal).

Inevitably, the lower the compression, the more space each image takes up on your memory card. The high compression setting (often called basic or low quality, file type: JPEG) will allow you to store the maximum amount of photos on your memory card.

Digital Zoom and Optical Zoom

Most digital cameras are equipped with either digital zoom, optical zoom, or both.

Digital Zoom
This is not a true zoom. It works by cropping and enlarging the image digitally. In other words, it cuts the outside edge off the image and then enlarges what is left.

Digital zoom actually manipulates the pixels, and therefore, the image inevitably ends up with some loss of quality. Digital cameras with only a digital zoom tend to be cheaper than cameras with optical or both types of zoom.

Optical Zoom
This is the same as a zoom on a conventional camera. It uses the optical lens of the digital camera to zoom. Optical zoom is far superior to digital zoom. If you want to be able to take clear photos from a distance without loss of quality, then optical zoom is a must.

Cameras with Digital and Optical Zoom
Digital cameras with both digital and optical zoom have the best of both worlds. Try and choose one that allows you to disable the digital zoom, as this will ensure only the optical zoom is used when required.

Internal (built-in) Memory Size

This refers to the amount of space that the camera has to store photos. Most cameras have the ability to accept memory cards (see below), so this shouldn't really be a major factor in choosing which digital camera to buy. You will see the memory size stated in MB (MegaBytes), typically around 16MB.

Memory Cards

Digital camera memory cards are used to store your images and allow an easy way to transfer your images to your PC via a media card reader. A lot of new PCs and laptops now have media card readers built-in, making the transfer process even easier.

As memory cards are removable, it is an idea to have more than one. This means that when you have filled one up, you can simply plug in the next and carry on taking pictures.

Memory cards vary in both type and storage capacity. Common types are SmartMedia, Compact flash cards, XD and SD Cards, with capacities ranging from 16MB to 512MB and above. If you already have memory cards from an existing camera, then it may be an idea to go for a camera with the same type.

Some digital cameras come with a memory card included. However, if they don't, then they are widely available to buy and the prices are quite reasonable, depending on the capacity of the card.

Below is a rough guide to the amount of images that memory cards can store, in conjunction with the type of camera used.

Shutter and Aperture Priority

What is the shutter?
The shutter on a digital camera is the same as a shutter on a conventional camera.
It can be thought of as an eyelid; the longer the eyelid stays open, the longer the image is viewed.

What is the aperture?
An aperture can be likened to the iris of an eye. It will open up to let more light in, and close to keep light out. On bright sunny days, the aperture will be almost fully closed.

What is Shutter and Aperture Priority
Some cameras allow you to alter the shutter speed and/or lens aperture. For example, if you were taking a photograph with movement, you may want a faster shutter speed to avoid blurs.

When you alter the lens aperture or shutter speed, the camera will adjust its counterpart. For example, if you alter the shutter speed, the camera will alter the lens aperture automatically.

LCD Screen size

This refers to the small screen on the back of some digital cameras.

It allows you to browse the photos/videos on your digital camera. Although the screen is generally too small to see the real image quality, it enables you to check the photo as soon as you have taken it.

The size of the screen that you want will be down to personal preference. Digital camera LCD screens range from around 1.5 inches (3.8cm) to 2 inches (5cm).