Skip to main content

Author information

Digital Cameras Explained - A Concise Buyer's Guide

0 Is this guide helpful? 232 23 Report

There are many choices available when choosing a digital camera. Therefore, choosing one can sometimes feel overwhelming to one who does not fully understand the terms used to describe the camera's features.  Whilst this guide is not an exhaustive work on how a digital camera functions, it will attempt to expand the reader's knowledge of important concepts in relation to digital cameras.  This will enable the reader to make a more informed choice when it comes time to purchase a camera which suits their needs.

After you finish reading this guide, please take the time to rate it. If you find this guide useful, please press the 'yes' button at the bottom of the page.

Types of Digital Camera

There are three main classes of digital camera; these being the simple compact or point and shoot, the prosumer and the Digital SLR.

Compact/Point and Shoot

Compact cameras on eBay

These types of camera are aimed toward the user who wants to produce good quality images with minimum effort.  Generally, these cameras operate in fully automatic mode, and will calculate the best exposure and other such settings for you.  These are often, equipped with scene modes, which allow you to choose what sort of environment you are shooting in, be it landscape,  portrait, low light, etcetera. This will give you a small amount of control over how the image is captured.  They will almost certainly always be equipped with movie mode.

These cameras are usually equipped with at least 3x optical zoom and 4-5 megapixel sensors.


Prosumer cameras on eBay

Prosumer, a combination of Professional Consumer, is a camera that is targeted toward a person who wants more manual control over how an image is captured.  You will generally be able to take full control over how the image is constructed, such as setting the shutter speed, aperture, focus, metering mode, ISO, etcetera, whilst also being able to take photos in fully automatic mode. These cameras differ from SLRs in the fact that they have a fixed lens, they are considerably cheaper, and they do not quite offer the superior quality of a Digital SLRs.  They do, however, in most cases offer an excellent alternative to Digital SLR cameras, as well as offering other features that SLRs are not equipped with such as movie mode and live-view. (Live-view is the ability to compose and view a subject on the camera's LCD screen)  One can also purchase wide angle or zoom attachments to increase the capabilities of the camera.

The standard for these types of cameras is usually 6-9 megapixels with 6-10x zoom.

Digital SLR

Digital SLRs on eBay

SLR is an abbreviation of Single Lens Reflex.  With an SLR, you view the image through to be captured through the lens, exactly as it will be taken.  These cameras are very expensive to buy, and have additional costs involved such as requiring additional lenses for different shooting situations.

These cameras are usually superior to the prosumer and compact, producing images that match the best quality film cameras.  The difference in image quality over a prosumer will be noticed mainly when the camera is capturing images at a higher ISO (ISO setting relates to the sensitivity to light, higher ISO settings allow for pictures to be taken in lower light with less exposure time)  whereby a prosumer camera capturing at 800 ISO will appear noisy or overly grainy, the SLR in most cases will produce a very clear and sharp image.  These cameras do not, however, come with movie modes and generally do not come with live-view (Live-view is the ability to compose and view a subject on the camera's LCD screen) due to the nature of the cameras design.

These cameras will suit a professional photographer, or an amateur photographer who wants to work with a more flexible camera.

Megapixels Explained

A pixel (a contraction of picture element) is the smallest component of an image. Put simply, a pixel is a small coloured dot, which combined, make up an image.  A megapixel, is a million pixels.

The more pixels your camera is capable of capturing, the better the detail and quality of image. Think of a pixel as a tile in a mosaic; the smaller the tile, the more detail can be represented by increasing the number of smaller tiles used.  The amount of megapixels required by you is dependant on how much you would like to enlarge the image, or how much you will crop from an image.  Small megapixel cameras are not able to be enlarged very much more than a standard photograph size; and cropping a small image will decrease the image quality further.  An image that has been cropped or enlarged past its resolution is characterised by a low quality blocky appearance.  Therefore, the more megapixels, the better your images will fare when being cropped or enlarged.

Above picture:  The first image is composed of 50 pixels and the second is composed of 500 pixels.  As you can see, the first image is blocky and devoid of detail, whilst the second is sharper and more detailed.

When choosing a digital camera it is vitally important to understand the difference between effective megapixels and interpolation.  For example, you may see a camera advertised as being capable of producing 10 megapixel images via interpolation, although it is oly equipped with a 3 megapixel sensor, or 3 effective megapixel capabilities.

Effective megapixels is how many pixels the camera sensor is physically able to capture.  Interpolation is an artificial process of building a larger image by inserting similarly shaded pixels around captured pixels.  This will produce a larger image, but it is not the best way of achieving this.  Buying a camera capable of taking a large megapixel picture without interpolation will always be better.


Zoom is the amount of magnification that the lens is capable of.  There are two types of zoom that are associated with digital cameras. 

Optical Zoom

As the name would suggest, this is achieved optically. The inner lens is moved inwards and outwards to achieve the magnification.  This type of zoom does not affect the quality or size of the resulting image, as the process is performed mechanically. 

Digital Zoom

Digital zoom works by cropping the resulting image, therefore reducing the amount of pixels from which an image is composed by the amount that was discarded in the cropping procedure.

When purchasing a camera, be careful of one potential trap.  Some manufacturers multiply the optical zoom by the digital zoom, and advertise the camera as having a very high zoom capability.  For example, if a camera has 5x optical zoom and 3x digital zoom, some manufacturers, and retailers will actually sell it as a 15x zoom camera. This, is however, very misleading and something you really need to be aware of.

Generally, disregard digital zoom, and purchase a camera with at least 3-4x optical zoom.

Memory Cards

Memory cards on eBay

There are many types of memory card on the market, the most common being Compact Flash, Secure Digital, Memory Stick and xD Picture Card.  When buying memory cards, it is sometimes a good idea to buy a few smaller capacity cards rather than one large one; if you lose one of these cards, then all is not lost, you still have another.  Memory cards are quite inexpensive these days, but be sure to check the postage prices on ebay before committing to purchase.

Some cards, such as the compact flash are good for cameras where write speed is an important factor, and are thus offered in high speed versions.  Most cameras, other than high end Digital SLRs, will not take advantage of this speed, therefore buying them for a standard camera is unnecessary.  Some Prosumer and Digital SLR cameras also allow for the use of different types of media.  Do some research to determine whether one of the memory cards performs better in a particular model of camera with this feature in order to choose the best media for that particular camera.


Batteries on eBay - Battery chargers on eBay

Cameras run on either rechargeable AA batteries, or specialized proprietary batteries which are unique to that particular camera.  When purchasing a camera it is important to consider what type of batteries you would prefer.  The following information will assist you in making a more informed choice.

Specialised proprietary batteries are usually Lithium Ion (Li Ion) powered; the same as most mobile phones.  These batteries can generally have a longer life, as well as lasting longer between charges.  The downside is that they are more expensive than AA batteries.

Rechargeable AA batteries are cheap to buy, and more convenient to use.  If you run out of batteries in the middle of the shoot you can easily purchase replacement Alkaline batteries to see you through until you charge another set.

The most common and best type of AA battery to purchase are the rechargeable Nickel Metal Hydride (Ni-MH) variety.  Batteries are rated in milliamp hours (mAH); a 2500 and over rating will be sufficient for most situations.  Other older types of Nickel Cadmium batteries should be avoided. They are not suited as much to digital photography applications, as well as being very harmful to the environment.

Chargers are also relatively inexpensive, with some better models being equipped with the option of in-car charging with a special cigarette lighter attachment.  This is especially good when on holiday; you can charge a spare set while you drive.

Some further advice regarding batteries:

  • Always be sure to use the correct charger type for your particular type of battery. Charging a different type of battery than what your charger was designed can be dangerous.
  • Don't attempt to charge non-rechargeable batteries.
  • Read the safety and operation instructions of all battery related equipment. 
  • Do not store batteries inside cameras for extended periods between use as the batteries may leak and damage your equipment.
  • Always dispose of your batteries in the appropriate manner, according to the local laws in your region.  Most batteries contain elements which are very harmful to the environment.
  • Special care should be taken not to submerge the camera or batteries in water. If submersion occurs, immediately remove the batteries, and contact the manufacturer for further instructions.. Batteries should be replaced if ever submerged (especially in the case of Lithium Ion batteries, as water can make them unstable).

Other Things to Consider

You should purchase a camera which will be able to grow with you, as your experience and knowledge grows.  A digital camera should not be purchased in  haste; research the different brands and models available, look at photography magazines and digital camera review websites.  Some review websites have extensive review sections, as well as sample image galleries; thus you can see the camera's capabilities without physically testing it.

If you are interested in pursuing photography as a hobby, learn about how a camera works and what features you may require to photograph particular subject matter.  If you purchase an inadequately featured camera for work outside of its capabilities, you will soon come to realise the limitations this will cause.  For example, to represent the movement of water flowing you will require a camera which is capable of being set to a slow shutter speed; sometimes a number of seconds will be required to capture a well exposed image, as well as achieving the desired effect. If you want to freeze movement in a dark environment you must be sure to purchase a camera that is capable of producing good quality images at higher ISO settings.  Knowledge and research is the key to avoiding disappointment.

Above Picture :  This image was taken at night with a shutter speed of 1.5 seconds. This gives the effect of motion as seen with the streams of light which are actually car headlights. A tripod is necessary for this type of photography as if the camera moves whilst taking the photograph, the image would be blurred.  A point and shoot camera would most likely capture this image without the streaming light effect, either by using a higher shutter speed and wider aperture combination, or a higher ISO (light sensitivity) setting.

Above Picture:  This picture was taken using a large aperture (F3.1) to achieve a narrow depth of field.  This enables the flower to be in focus, whilst the background is blurred.  Point and shoot cameras would most likely capture the image with all aspects in focus, which would in this case distract from the main subject of the photograph.

Above picture:  Interesting silhouette effects can be achieved by setting a camera manually - even more successfully on a prosumer camera with live-view, whereby you can see how the photograph will turn out before you capture it..  On an automatic camera, the image may turn out a little more overexposed as the camera tries to achieve the correct exposure for all objects in the photograph, but every camera is different.

In closing, you will need to find the right camera to suit you, and more importantly your budget.  As stated earlier, don't rush, research.  And if you don't want to be an artist, your simple compact camera will suffice and will hopefully provide many years of trouble-free service; however if you want to go further, the prosumer and Digital SLR cameras are for you.

Related Items

See all related items
Choose a template

Additional site navigation