Digital Cameras - Digital Camera Reviews - Digital Photography

35 mm Camera

Photography has developed rapidly over the years with equipment and film working in tandem to pioneer new methods of taking pictures. 35mm film, also referred to as 135 film, can be used for still photographs and motion pictures. The 35mm camera was put on the market in 1934 and was a best seller by the late 1960s and still enjoys success today.

]]> Standards were adhered to in the industry and the usual film format is 24x36mm, allowing for 2mm gaps between frames. The standard roll length is 36 exposures but 12 and 24 exposures are also popular for today's 35mm camera. Some disposable cameras, used for taking holiday snaps and for special occasions, tend to use 6, 8, 10 or 15 exposure film.

The first still camera to become popular with the public, using 35mm film was the American Tourist Multiple, which began selling in 1913. The new invention cost a lot of money for the times. It was the 1925 Leica 35mm camera however, that really set the seal of success on this type of product. The German produced camera quickly became a status symbol and was widely praised for its small size, quality lens and high production levels. The Leica continued its popularity and was championed by professional photographers, including fashion photographers, photojournalists and art photographers such as Henri Cartier Bresson.

In 1934, the Kodak Company launched the German built Kodak Retina, the first 35mm camera to use the modern film cartridge, familiar to camera users today. The next important innovation took place in the 1960s when Nikon introduced the Nikon F SLR. This was the beginning of the Single Lens Reflex system, a technology that went on to dominate photography. This type of camera proved more user friendly with functions such as a viewfinder, focusing screen and motor drive to automatically move the film on.

The introduction of digital cameras made a huge impact on the market but Digital SLRs have gained in popularity as the price has decreased and the 35mm camera is once again, secure. These cameras combine the convenience of a digital camera with the flexibility and quality of an SLR. Today, the camera and film market is shared by Kodak, Ilford, Fuji, Nikon, Olympus and Canon. The technology will, no doubt, evolve once more into territory not even thought of as yet but there will always be a place of affection for those early cameras that people grew up with.

WiFi Comes to Digital Cameras

First we had to get over the whole film thing after a nation of baby boomers had been raised on Kodak, Polaroid, and 35mm film cameras of various shapes and sizes. We were all use to the idea of sending in our film for developing and waiting for our pictures to come back.

]]> Then along came digital cameras and the world was taken by storm with this cool new technology. Suddenly you could take a picture and see the results immediately. At first these cameras were slow and not such great quality but still kind of cool. Then things heated up and now we have fantastic digital cameras of all sizes and shapes that can take wonderful images which can be shared instantly with your family, or the rest of the world for that matter.

Now comes the latest in technology integration. WiFi and digital cameras. No need to even plug your camera memory card into a computer, or a printer at all. Now you can buy a digital camera that transmits the images via wireless technology. Yes, that is right, a wireless connection for your image uploads.

Now, you may be among those in the population that have not even gotten their hands around the whole digital image sharing thing yet. But this promising new technology may lead us to a world of fewer cables to plug in, quicker transfer of our images, and in the case of events in the world, the ability to share images of news almost instantly.

As we saw in the recent bombings in London, folks with cell phone cameras recorded the devastation they saw in the underground and shared it with the world in almost real time fashion. These new cameras may be able to take that sort of thing to an all new level. Imagine cities that implement widespread WiFi access and photographers with WiFi cameras capturing images of news and other special events. They could transmit those images right away and let the world see them.

Here is how it works:

Nikon has released two models of digital cameras that are WiFi enabled. The idea is to be able to transmit your pictures straight from the camera to your computer or printer through a wireless adaptor. You bring up the images to transfer, hit “go”, and they get sent through the air to your printer. The Coolpix P1 and P2 will be in the $400-$550 range in pricing and the adaptor is extra.

They are competing with Kodak which released its own version of the WiFi camera in their Easy Share line of cameras this year. Kodak has already gone to making it easy to share photos by transmitting them at so called "wireless hot spots", usually cafes or stores where wireless access is sold or given away to customers. These efforts by the leading camera makers seem aimed at adding value to their already impressive digital technology.

Digital cameras continue to be hot sellers despite what some in the industry thought would be a slowing of sales this year. Many had predicted that cell phone cameras would slow digital camera sales, but this is not happening.

If you are a leading edge gadget buyer and have a wireless mindset then you may want to be first on the block to get one of these Wi-Fi digital cameras.

Batteries for Digital Cameras

Digital cameras are electronic devices so they need a power source of some kind. The most convenient way to power your camera is with batteries. Although some models can be connected directly to an AC outlet, this is impractical for anything but studio use.

]]> Batteries are used to power the flash and the LCD display. Leaving the display on more than necessary is a surefire way to drain your batteries, and if you don't have a spare set on hand, that once-in-a-lifetime photo can be lost. Most digital cameras use AA batteries. These are available almost anywhere in the world and relatively inexpensive. Using nonrechargeable batteries, however, is uneconomical in the long run as well as being bad for the environment. It is much better to have several sets of rechargeable batteries on hand.

Digital cameras are 'high drain' electronic devices which mean they require batteries which have a comparatively high energy level over their energy cycle. The best type of rechargeable batteries for digital cameras is NiMH (Nickel-Metal Hydride). These relatively inexpensive batteries will keep your camera operating longer than any other standard type of battery. NiMH batteries are made from non-toxic materials so they are environmentally friendly.

Some manufacturers supply lithium-ion batteries for their digital cameras. They are more expensive than NiMH batteries but hold their charge almost twice as long. They also don't lose their charge while in storage the way that NiMH batteries do, and their power drains at a predictable rate so that it is easy to gauge how much power is left.

Alkaline batteries are not suitable for digital cameras. You can always use them if nothing else is available, but their power will be used up after just a few shots. Rechargeable alkaline batteries are even worse -- they may only be good for two or three shots.

A set of fully charged NiMH batteries may give you up to 100 shots if you are careful with power consumption. This number will be reduced if you use the flash a lot, leave the monitor on between shots, and do a lot of zooming and focusing.

Battery Chargers

Battery chargers come in a variety of models – be sure to get one that is rated for the type of batteries you are using for your digital camera. Some chargers can handle both NiMH and NiCad batteries but if these chargers are not set up properly they can damage the batteries by overcharging them.

Lithium-ion battery chargers are usually provided by the camera manufacturer. They may come as part of the digital camera package or be available as an accessory. Batteries have to be charged together as a set. If your digital camera uses four AA batteries you need a charger that can handle that number. Similarly if your camera uses two or three batteries -- the charger must be compatible.

Some of the inexpensive battery chargers keep on charging the batteries for a fixed length of time. This can be bad for the batteries because they can be overcharged. Look for a battery charger that has a micro processor which controls the charging cycle. This type of charger switches off automatically when the batteries reach their maximum charge.

Camera Tripods

Tripods are a necessity for anyone who wants to take the best pictures possible. They are useful for many different situations by helping to minimize camera movement which can cause an image to blur.

]]> Blurring is especially noticeable in photographs taken with extended exposures (under low-light conditions, for example) and becomes more apparent when photographs are enlarged. Even slight motions of the camera can cause blurring. Supporting the camera can help to reduce camera movement. A tripod provides the best support, but cameras can also be stabilized with objects such as doorframes or tree trunks. Monopods are suitable for outdoor use when tripods are either too heavy or too cumbersome to set up.

There are hundreds of tripods to choose from in a broad range of prices. The most expensive ones are made of composite materials such as carbon fiber which is lighter and more durable than either aluminum or alloy. Expensive tripods are usually equipped with quick release mechanisms for adjusting the legs and the camera mount.

Each tripod has three heights which must be considered -- maximum, minimum, and collapsed. For most purposes, the maximum height should allow you to use the camera at a comfortable standing position. You rarely need a tripod higher than this. If you do a lot of close-up work, the minimum height is an important measurement, although extensions can be added to the head which allow the camera to be brought close to the base of the tripod. Finally, the collapsed height is important to determine the tripod's portability -- compact tripods are usually easier to carry around.

Tripods usually have a center column to attach the tripod head. This center column can be used for fine height adjustment and some models allow the camera to be tilted down towards the ground for closeup work. Look for a center column with a hook – these can be used to hang heavy objects for increased stability.

Tripod heads are the part of the tripod that the camera attaches to. They allow the camera to swivel and move up and down. This movement is accomplished with two basic types of head – the three-way pan tilt head, and the ball head.

Traditional heads are the three-way pan tilt type. They have three different axes and each is controlled with its own mechanism and lock. The locking mechanisms make this type of head ideal for situations where precise control of the visual field is needed, but can be inconvenient for other uses.

Ball heads allow all three axes to be set at the same time, so they are easier to use. They are also more expensive but most photographers gladly accept the higher price for the increased flexibility in camera movement.

Monopods are an ideal alternative to tripods where portability is a concern. They consist of a single support which the camera is mounted on. Outdoor photographers often prefer monopods over tripods because the latter are bulky and difficult to set up.

Using a monopod is almost as easy as pointing and shooting. The monopod gives the camera the extra stability necessary for good quality shots.

Carrying a tripod is easier with a case or a carrying strap. Cases can be used to hold all your camera equipment but are bulky to carry around. If you don't have a lot of equipment a shoulder strap is the best solution for carrying the tripod. If the camera needs to be perfectly level, small bubble levels can be attached to the tripod. Some tripods come equipped with levels, but they are also available as inexpensive accessories.

Lenses for Digital Cameras

There are two major components of digital cameras that play a big part in image quality – the image sensor and the lens. Get the best you can afford -- good quality lenses are essential for getting the most out of digital photography.

]]> Lenses are available in various focal lengths which determine field of view and depth of focus. As they become longer they can focus on smaller areas but require more precise focusing to obtain a sharp image. Longer lenses are also more susceptible to movement and will likely blur images if the camera is moved during a shot.

Long lenses are sometimes called telephoto lenses. Because of their reduced field of view, the images shot with telephoto lenses are magnified compared with shorter lenses. Similarly, shorter lenses give a wider field of view, so very short lenses are called wide-angle lenses.

A 'normal' lens is one that produces an image similar to what the human eye sees. There is no standard length for a normal lens because field of view is directly connected with the size of the image sensor that captures the photo. A 50mm lens is considered normal for traditional 35mm cameras but digital image sensors are much smaller than a frame of 35mm film, so shorter lenses on digital cameras will capture the same field of view as the 50mm lens on a 35mm camera. The specifications of a digital camera lens will often include a reference to how the focal length compares to a 35mm camera.

Almost every digital camera has an optical zoom function that changes the focal length of the lens. They are rated as a multiplier – a 3X zoom will enlarge or reduce an image by 3 times from the longest to the shortest setting.

Some cameras are also equipped with a digital zoom. These work by cropping the image digitally and then spreading the result over all the photosites on the image sensor. This is inferior to optical zoom and should not be used. Better results can be obtained by editing the photo using computer software.

Most digital cameras in the mid-range and better have the ability to add lens converters. These give you more options for digital photography by allowing you to attach various types of lenses and filters.

In addition, many digital cameras can accept lenses made for film cameras. Because of the difference in size between film and image sensors, however, these lenses do not produce the same results as with film cameras. A telephoto lens designed for film will have a larger magnifying effect, and a wide angle lens will have less effect on a digital camera.

Lenses are quite expensive. They should be kept in cases and covered with caps when not in use. Most lenses come with caps but you may have to buy extras in case they are lost. They are widely available and fairly inexpensive.

Lens hoods are useful for controlling the amount of light entering the lens. They result in images that have less contrast – useful for some outdoor situations.

Lens cleaning kits are available but should be used as infrequently as possible. Avoid touching the lens with your fingers as the oils in your skin can cause permanent damage to the lens coating. Wipe fingerprints with a soft cloth but first remove dust particles with a blower. Larger dust can be removed with a soft brush.

Classic Photography vs Digital Photography

Even though digital photography is a revolutionary new way to take pictures, it is very much based on traditional photography and uses many of the same principals. Both types of photography require a lens to focus the light and a shutter to allow the light to enter the camera. The main difference between digital and traditional photography is how the image is captured.

]]> Traditional photography uses film which must be developed in a darkroom using various chemicals. The developing process produces 'negatives' which must be printed before you can see the picture. Digital photography uses an electronic sensor to capture the image. The sensor is made up of millions of individual 'pixels' (picture elements) which convert light into a number. Rather than waiting for the picture to be developed, digital pictures can be seen almost instantaneously on the viewfinder of the digital camera.

The quality of a digital photograph depends a lot on how many pixels it has. The number of pixels is sometimes referred to as the 'resolution' of an image, and can be expressed as a dimension (800 x 600), or the number of pixels per inch. A common resolution for computer screens is 800 x 600 and this means the monitor can display 800 pixels from side to side and 600 pixels from top to bottom for a total of 480,000. Digital photography commonly uses much higher resolutions than computer screens with resolutions in the millions of pixels (megapixels). A camera with a resolution of 2048 x 1536 has a total resolution of 3.1 megapixels.

As mentioned above, each pixel is represented by a number. The size of that number determines the colours scale that can be represented. For example, black-and-white pictures can be represented with pixels which are just eight bits in length. If you are familiar with binary arithmetic, you know that an 8-bit number can represent decimal numbers from 0 to 256. Black-and-white photographs, therefore, can have a total of 255 shades of gray as well as black (0) and white (256).

Colour must be represented with larger numbers. 16 bits per pixel, for example, is necessary to have a colour scale of 65,536 different shades. 24 bits per pixel can represent more than 16 million different colours. Most digital cameras use 24 bits per pixel, but some professional equipment has a colour resolution of up to 48 bits per pixel for more than 280 billion different shades.

There are several factors that affect the quality of a digital camera, but pixel resolution is usually seen as the most important. Choosing an adequate pixel resolution depends a lot on the size of the photographs you want to print. Keep in mind that the number of pixels in an image does not change, so pictures with larger dimensions will have fewer pixels per inch which results in a loss of detail if the picture size becomes too big.

Photo labs usually print pictures at 300 pixels per inch, so using this as a standard measurement you can calculate how many megapixels your camera should have. The maximum print from a two megapixel camera at 300 pixels per inch is 5.8" x 3.8" -- less than the standard 4" x 6". A camera with four megapixels can print pictures to a maximum size of 8.2" x 5.4" at 300 pixels per inch.

Of course, there is nothing to stop you from printing larger pictures. Pictures printed at 200 pixels per inch are slightly less sharp but still quite acceptable for many purposes. At this resolution, you can get pictures up to 8.7" x 5.8" from a two megapixel camera, and 12.2" x 8.2" from a four megapixel camera.

Digital Camera Buying Guide – Part Two

The simplest digital cameras are point-and-shoot cameras -- simply aim them and push the button. They are very easy to use and are suitable for people who simply want to take family or vacation snapshots. The downside to point-and-shoot cameras is the lack of control you have over focusing and image adjustment. As you go up the scale to more expensive cameras, you get more of these kinds of options. The simplest point-and-shoot cameras often have a low megapixel rating -- around two megapixels.

]]> Slightly better cameras in the three to five megapixel range usually also have more controls for focusing and image adjustment. Prosumer models are designed for those who are serious about photography but don't have the budget for professional equipment. Professional digital cameras offer the greatest flexibility for capturing digital images. These cameras are the most expensive and can cost several thousand dollars.

You are presented with many choices when buying a digital camera. There are different types of image sensors, storage cards, batteries, as well as extra features like video and audio recording. As mentioned in the previous article, image sensors and lenses are the most important parts of a digital camera for capturing quality images. They are not the only things to consider, though.

Controls

Many of the controls on digital cameras are accessed through a menu system. An easy-to-use menu system is a great benefit to any digital photographer, so this is an important point to consider when shopping around. The menu system should be clearly laid out so that you can access settings such as resolution, flash, and exposure settings. Too many buttons can be confusing and can inhibit the average user from accessing all the features.

Exposure Settings

Exposure settings allow you to adjust the camera for various types of light. Almost all digital cameras have an automatic mode which will do the adjusting for you, but better cameras will give you more control over aperture settings and exposure times. These can give your photos a more professional look, but some people may not be interested in this level of control.

Video and Audio

Many digital cameras allow you to shoot videos and/or record sound. These features can be handy, but the amount of video that can be captured is quite small compared to a dedicated camcorder.

LCD Display

LCD displays allow you to see pictures you have taken. This is essential for deciding which shots to keep and which to discard. The display may also function as a viewfinder allowing you to see how your shot will look before you press the shutter button. Some of the cheapest digital cameras do not have an LCD display.

Software

Some cameras come bundled with image-editing software like Adobe Photoshop Elements or Ulead PhotoImpact. Software is a great way to edit your photos before they are printed. Software packages can cost up to $100 if bought separately so having it included with the camera is a serious buying consideration.

Try Before You Buy

If possible, take a few pictures with a digital camera before you buy it. This will give you a feel for the controls and the ease of use. How does the camera feel? Is it solid or does it seem like a plastic toy? Is the LCD screen easy to view under various lighting conditions? Giving the camera a tryout will answer these questions.

Digital Camera Buying Guide – Part One

Are you ready to take the plunge into the world of digital photography? This series of articles will help you choose the best camera for your needs.

]]> The first thing to consider is why you want a digital camera. The answer to this question will form the basis of all your other buying decisions. If you simply want to send snapshots by e-mail or post images on the Internet, you don't need a high resolution camera. If you want to print digital photographs, however, you need a camera with more resolution.

Resolution

Digital cameras are rated by the number of megapixels (millions of pixels) they can record. This is also referred to as their 'resolution' and is the single most important factor affecting the price of digital cameras. Quite simply, the more megapixels the higher the price.

Images which are only viewed on a computer screen did not need a high resolution. A computer monitor set to 1280x1024 (which is very large) is only displaying about 1.3 megapixels. Any digital camera rated at about two megapixels is suitable for computer images.

Printed pictures, however, are another story. Professional photo shops usually print photographs at 300 dots per inch, and you are likely to be disappointed with pictures printed at less than this standard. A 4 x 6 photograph printed at 300 dots per inch needs an image which has about 2.8 million pixels. That means that digital cameras that are meant to be used for printed pictures should be rated at least three megapixels.

More megapixels doesn't necessarily mean better pictures. All other things being equal (image sensor quality and lens quality) a camera with more megapixels simply allows you to print larger pictures. You also have more options for cropping photos and maintaining standard print sizes.

Budget

Now that you have chosen a minimum megapixel rating, you can look for cameras which fall into your budget. You will most likely want to get the best quality images for your money, and that may mean foregoing some of the fancy features such as video and sound recording. Concentrate on lens quality and image sensor quality.

Lenses are available in either plastic or glass. Glass lenses are superior and will produce crisper, cleaner images. The best cameras will be equipped with lenses by well-known manufacturers such as Leica or Zeiss.

Many digital cameras have a zoom function which allows you to get closer to your subject without moving the camera. There are two types of zoom -- digital and optical. An optical zoom changes the actual length of the lens. Digital zooms simply remove the outside edges of an image and interpolate the result over the area of the image sensor. They do not give as good results as optical zooms and should be avoided if possible.

Image sensors are electronic devices that record the images. The two most popular types are CMOS (Complementary Metal Oxide Semiconductor) and CCD (Charged-Couple Device). CMOS is the cheaper of the two but the image quality is inferior to CCD.

No matter what your budget, a camera with a good quality lens and CCD image sensor will likely give you pleasing digital photographs.

How a Digital Camera Works

Digital cameras are quite similar to traditional cameras in their operation. They both have a lens to focus the image, a shutter to allow light inside the camera, and an aperture to control the amount of light which enters the camera.

]]> The differences between digital and traditional photography occur after the light enters the camera. A traditional camera captures the images on film, while a digital camera captures the image on an image sensor.

Image sensors are electronic devices made up of an array of electrodes (or photosites) which measure light intensity. The most common type of image sensor for digital cameras is the CCD (Charge-Coupled Device) although others such as CMOS and Foveon are sometimes used.

The number of photosites in the image sensor gives the digital camera its megapixel (millions of pixels) rating. Each photosite corresponds to a pixel in the final image, so a camera which is rated at six megapixels, for example, has an image sensor which is 3008 pixels wide by 2000 pixels high.

When light hits the image sensor it is converted into electrical signals which are amplified and fed to an analog-to-digital (A/D) converter. The A/D converter changes the electrical signal into binary numbers which are processed by a computer housed in the camera body. Once the numbers have been processed the resulting image is stored on a memory card.

Photosites can only measure intensity of light -- not colour. In order to produce a colour image, each photosite must be covered with a coloured filter which can be red, blue, or green. These are the three primary colours which can be combined to produce any other colour including white.

The coloured filters are arranged in a grid so that there are twice as many green filters as there are red or blue. This is because the human eye is twice as sensitive to green light. Filters are arranged in a pattern called the Bayer pattern - one row of red, green, red, green (etc.), and the next row of blue, green, blue, green (etc).

Since each photosite can only be covered with one coloured filter, computer processing is necessary to produce a full coloured image. This is done by analyzing each individual pixel and its immediate neighbors and producing a composite colour from these calculations. For example, if a bright red pixel is surrounded by bright green and bright blue pixels, the bright red pixel must actually be white, because white is the combination of red, blue, and green. This process is called demosaicing.

After demosaicing the image is adjusted according to the settings on your camera. Most cameras have settings for brightness, contrast, and colour saturation. After these adjustments are made some cameras may also apply a sharpening algorithm to make the image clearer.

The final step before saving the image on the memory card is to compress it. Most cameras use JPEG as a compression format. This reduces the size of the file by eliminating excess data. This data cannot be recovered, so JPEG is called a 'lossy' format.

Many cameras have the ability to save uncompressed images as TIFF files or raw data. Raw data is the original photosite data even before demosaicing. It can be transferred to a computer for processing with special software that will perform all of the processing functions of the camera but with much greater control.

Using Flash

Automatic flash is a great tool for solving common lighting problems, but unless used with care it can create some problems of its own.

]]> Almost every digital camera is equipped with automatic flash. Most cameras have several flash settings for different lighting conditions. The flash can be set to automatically trigger when the light conditions are too dim, and there are usually several other settings for greater control over the flash.

The flash is usually integrated into the body of the camera. This is very convenient -- just shoot the camera and allow the flash to come on if it is needed. There are, however, a few problems related to the close proximity between flash and lens.

The most common problem is red eye. Everybody has seen this -- the eyes of people (and even animals) take on a weird red glow. This is caused by the light from the flash reflecting back from the retina of the eye. The thin red blood vessels in the retina cause the red colour.

Some cameras have a flash setting which reduce this red eye effect. This works by firing a short flash before the picture is taken which causes the iris of the eye to become smaller.

Another problem caused by integrated flash is a lack of depth. The reason for this is the even illumination over the entire surface of the subject. Shadows which normally give a sense of depth are eliminated.

Both red eye and flatness can be reduced with a separate flash unit. They can be powered with a 'hot shoe' (a bracket on the camera body) or a cable which synchronizes the flash with the built-in flash of the camera.

By moving the source of the flash away from the lens, added depth is created and the subject's eyes are not directly illuminated. External flash units also give you more options for aiming the flash -- the light can be bounced off other objects for a more subtle effect.

Not all flashes are created equal. They are available in various strengths, and the power of the flash determines how much area it can light up. Most manufacturers specify the maximum range of a flash. This distance can be achieved when the aperture of the camera is fully opened.

Objects which are closer to the flash will appear brighter. This effect can be used for separating your subject from the background, but it can also create problems if you wish to capture several people or objects which are at various distances from the camera. The only solution to this is to pose your subjects so that they are all at the same distance from the flash.

Besides auto mode and red eye reduction mode, most digital cameras have several other flash settings. Flash off mode can be used to override the flash completely, allowing you to compensate for low light by increasing the aperture opening. Fill flash mode is useful when there is a bright light source behind your subject which would otherwise cause the picture to be too dim. Slow sync mode causes the shutter of the camera to remain open longer than normal. This allows the camera to absorb the ambient light after the flash has fired to create a more natural effect.

Creative use of the flash settings can allow you to achieve special effects. For example, slow sync mode can be used to blur the background of a picture while keeping the subject sharply focused. This is achieved by moving the camera slightly after the flash has fired.

Memory Cards

Traditional photography uses film as a storage medium. When one film is used up, simply take it out and pop in a new one. The film is eventually developed and the stored images printed. Digital photography also has a form of removable storage - memory cards. The advantage of these cards over film is that they can be erased and reused. Images stored on memory cards can be transferred to a computer for further processing and permanent storage, or they can be transferred directly to a printer. Memory cards are not the only medium for image storage, but they are the most common. Other storage media include removable hard drives and optical disks.

]]> Memory cards come in a variety of sizes, so you need to figure out how much storage space is required for your photos. This can vary according to the megapixel rating of your camera, the type of storage format, and the amount of compression used to store the images.

The most common type of compression is JPEG, but this is a 'lossy' format. This means that some of the data that makes up your image is discarded and cannot be retrieved. For most purposes this loss of data is not critical to the quality of the image and the savings in terms of storage space more than compensate for the lost data. Sometimes, however, lossy formats are not acceptable so the image has to be stored without any compression at all. This requires significantly more storage space than JPEG.

CompactFlash

CompactFlash is the most popular type of memory card for digital cameras. It is relatively inexpensive and is widely available. It is used by a number of different camera manufacturers, so if you buy a new camera, chances are it can use CompactFlash. There are two kinds of CompactFlash cards -- Type I and Type II. Some cameras can only accept one type, so it is important to know which one you need for your camera.

Secure Digital / MultiMedia Card (SD/MMC)

SD/MMC cards are the smallest type available. SD/MMC are identical except that SD cards have a write-protect switch which prevents images from being accidentally erased. They can be used in ultracompact cameras and also in personal entertainment devices like MP3 players. SD/MMC cards have less maximum storage capacity than CompactFlash cards (currently at 1 GB) but still offer enough space for most digital photography needs.

xD Picture Cards

xD Picture Cards are also very small -- less than 1 inch square. They were developed by Olympus and Fuji and are most commonly used in those brands of camera. They can be used in other types of cameras with a CompactFlash adapter.

Memory Stick

Memory Stick was developed by Sony and is used in almost all Sony digital cameras. It can also be used in other Sony devices like MP3 players and PDAs. Memory Sticks are used on very few other cameras beside Sony cameras, so switching to another brand will most likely mean being unable to use this memory.

MicroDrive

A MicroDrive is an actual hard drive housed in a CompactFlash Type II casing. Because they are mechanical drives with moving parts, they are somewhat more delicate than flash memory cards. They must be handled with care and are more prone to breakage. MicroDrives also have a slower access time than CompactFlash cards, but have the advantage of larger storage capacity at cheaper prices.

Advantages of Digital Photography

Digital technology is finding a place in almost everyone's lives. From digital music to digital movies we are constantly exposed to images and sound that have passed from the traditional analog domain into the new digital formats. Digital photography is one of those formats and is becoming more popular every year.

]]> There are lots of reasons for that popularity. Digital photographs are incredibly versatile. You can send them to friends and family by email, post them on a web site, transfer them to CD, store them on your computer, and use them for slide shows which can be viewed on your TV or computer monitor. They can of course be printed, and not just as traditional 4x6 pictures. They can be used to make personalized calendars, greeting cards, and even be printed on objects like coffee mugs and t-shirts.

For many people, the biggest advantage of digital photography is that it eliminates the need for picture processing. No more trips to the photo store – pictures can be viewed almost instantly on the display screen of the camera. Since there is no developing, digital photography doesn't need dangerous chemicals that could end up in our water supplies.

Another big advantage of digital photos is the ease with which they can be edited. Computer software allows digital images to be altered in any way imaginable. They can be cropped, the colours can be changed or enhanced, the contrast can be adjusted, imperfections can be removed, and images can be combined to create startling new designs. All this can be accomplished in a few seconds with just a few key strokes or mouse clicks.

Using a digital camera is the best way to take advantage of all the features of digital photography, but you can also use a traditional film camera and convert your negatives to the digital domain. If you are uncertain about whether or not to take the digital plunge, converting negatives allows you to get a taste of the wonders of digital photography without investing in new equipment. Most photo developing stores offer this service.

Digital cameras, however, offer so much more than film cameras. They have a viewing screen which functions as both a view finder and a picture viewer. This means you can preview pictures you've taken just seconds before. If you don't like it just delete it, or if there is a section that is good, crop it before saving it back to the camera's memory. Many digital cameras also function as simple video recorders that can capture video along with sound - anywhere, anytime.

All this must come at a hefty price tag, though - right? Wrong! Digital photography is becoming more affordable every year, and the technology to make fabulous photos is well within the reach of the average consumer. Add in the money you'll save in development costs and you have an affordable, practical, solution for all your photography needs.

Aperture

Digital photographs are the result of light hitting the image sensor. Too much light and the photograph will be washed out. Too little light and the photograph will be too dark. The shutter determines how much light enters the camera, and there are two settings which are related to the shutter -- aperture and shutter speed.

]]> Aperture is the size of the opening between the lens and the image sensor. Large apertures allow more light to enter the camera than small apertures. Apertures are expressed in 'f' numbers -- the higher the number the smaller the aperture. Standard lenses are usually rated between f/1.8 and f/16.

Each f-number allows twice as much light to enter the camera as the previous f-number. For example, f/8 produces an exposure which is twice as bright as f/16.

Aperture settings have two basic effects -- the amount of light which strikes the image sensor, and the 'depth of field'. Depth of field refers to the length of the image which is in focus. Large aperture settings have a shallow depth of field -- this means that the focus of an image is relatively short which causes foreground and background objects to appear out of focus. Small apertures have a deep depth of field -- almost all the objects (foreground and background) will remain in focus.

Aperture is directly related to shutter speed for determining the amount of light that enters a camera. Large apertures combined with fast shutter speeds let in the same amount of light as small apertures combined with slow shutter speeds. Determining which combination is best for a particular situation requires photographic judgment that comes with experience.

To make it easier, most cameras have an automatic setting which will do the calculations for you. Many photographers, however, wish to control aperture and shutter speed for artistic effect.

Since a large aperture can be used in conjunction with a fast shutter speed, this is often a good combination for action shots because the fast shutter speed will 'freeze' the motion with a minimum of blurring. Large apertures can also be used for low light conditions where there is very little movement in the scene. In this situation you would combine the large aperture with a slow shutter speed.

Simple point-and-shoot cameras usually have a fixed aperture, and it is only with more expensive models that you have adjustable aperture settings. When choosing a digital camera, one consideration should be the aperture range. There are several ways this can be expressed in the camera specifications: maximum aperture, aperture range, maximum wide-angle and maximum telephoto apertures.

It is more useful to know the aperture range of a particular camera rather than the maximum apertures. A larger range gives you more flexibility in the kinds of shots you can take. A good range for all-purpose photography is from f/1.8 to f/16.

Each lens has its own aperture rating. Telephoto lenses typically have a shallower aperture range than wide-angle lenses because longer lenses need proportionally more light. This is because they are gathering light from a smaller source, so larger apertures are needed to produce f-numbers which are consistent with shorter lenses.

Digital Photography Lighting

A photograph is essentially a record of the light conditions at a certain point in time and space. We recognize the patterns of colors and shapes in a photograph because they resemble what we see in daily life. Light is so common that we take it for granted, but the photographer (and the painter) needs to be attuned to the subtlety of light in order to make effective pictures.

]]> What we consider to be 'white' light is actually made up of all the colors of the spectrum. This is easy to demonstrate with a prism – let light shine through it and it will refract into all the colors of the rainbow. In fact, we see rainbows because water droplets are acting as prisms by breaking up the white light from the sun and splitting it into colours.

Objects have different colors because they reflect those colors while absorbing the others. Black absorbs all color – it is the absence of colour.

Even though all light may look alike to us, different light sources emphasize certain parts of the color spectrum. Bright sunlight from about 10 am to 2 pm, for example, has a bluish tinge. Early morning and late afternoon sunlight is red because it is filtered through the earth's atmosphere.

Artificial light also has distinct color characteristics. Incandescent light brings out red colors while florescent light is greenish-blue.

The photographer can take advantage of these different characteristics when taking shots. Either the camera can be adjusted to compensate for the light source or the special characteristics of the light can be used for artistic effect.

Most digital cameras can be adjusted for color balance. There may be several options – auto, manual, daylight, incandescent and flash. They can be used to compensate for the light source so that white is truly white. This allows the colours to be reproduced accurately.

In some cases you may wish to get a special effect by altering the white setting to a different colour. You can preview how this will look on the LCD monitor.

The direction of the light source is a very important consideration in photography. Light can come from above, behind, below or the side of the subject and each produces a different effect. Generally speaking, a diffuse light coming from the sides will be a good starting point when photographing people. This kind of light occurs in the early morning and late afternoon, or can be produced in the studio with an umbrella reflector.

Of course, all kinds of special effects can be produced by lighting your subject in different ways. Backlighting can create a halo effect, while overhead lights can create strong contrasts between light and shadow.

Another factor which affects photography is the strength of the light. Direct light creates strong shadows while diffuse light can create a warm atmosphere by reducing the contrast between objects. The beauty of digital photography is that you can experiment to your heart's content without running up film or processing costs. Get ideas for lighting by looking through photography books and trying out various types of lighting to see what works for you.

Transferring Digital Images

After you have taken enough photos to fill out up your memory cards you need to transfer them to a computer or printer. There are several ways to do this.

]]> Almost every digital camera on the market today has a USB port. This allows the camera to be connected directly to a computer for image downloads. There are two versions of USB – USB 1.1 and USB 2.0. High-end cameras are usually equipped with USB 2.0 because the transfer rate is up to 10 times faster than USB 1.1. Budget cameras usually have USB 1.1 – adequate, but other options may be more attractive.

Rather than reading the images directly from the camera, they can also be read from the memory card. Most multimedia notebook and desktop computers can read cards directly. If this is not the case you may need an external card reader.

Card readers are one of the most efficient ways to transfer images. Simply take the card out of your camera and pop it into the reader. Most card readers have a variety of ports designed for different kinds of memory cards. Card readers are almost always equipped with USB 2.0 or FireWire -- an equally fast data transfer protocol. They are quite reasonably priced.

One of the advantages of USB devices is that they can be connected to the computer while it is turned on. The computer will recognize the card reader as an external storage device and allow you to transfer data to any location on the computer's hard drive.

Other Options

For most people, storing images on a computer hard drive is the most practical solution. Computer storage allows images to be edited, sent as e-mail attachments, or posted to a web site.

However, there are other ways to download images from your camera. Cameras with a PictBridge or USB Direct Print can be connected directly to a compatible printer for direct printout. This is a very convenient way to download pictures but by doing so, you miss out on the opportunity to edit them on the computer.

Another way to transfer images is to use the camera's video output to connect it to a TV, VCR, or DVD burner. Images could be captured on videotape or burned to DVD, or simply viewed as a slideshow on a TV screen. Some cameras are equipped with an infrared remote control which allows you to flip through the pictures from your armchair.

Portable Storage

Portable storage devices are specifically designed to hold large numbers of images so that they can later be transferred to a computer. They are primarily aimed at the professional photographer who shoots several gigabytes of photographs per day. These devices are also useful when you are on vacation and taking lots of photos and don't have easy access to a computer.

These devices have an internal hard drive and are powered with rechargeable batteries. They read the camera's memory cards so that they can be erased and used again. They are often equipped with a LCD viewing screen so that images can be previewed. Images are transferred to the computer by USB 2.0 or FireWire.