Digital cameras have become one of the most popular new consumer items. As is common for many high technology items, the price of digital cameras has fallen, as the technology improves. The dramatic increase in sales of digital cameras is mostly due to their "instant gratification" by eliminating the cost and inconvenience of film and processing. Another advantage is the ease of editing digital photos. The increase in sales of digital cameras has often more than offset the decline in sales of film cameras and accessories. Also, digital photography has in some cases, replaced film photography in many professional applications. According to Olympus, one of the leading digital camera manufacturers, the high-end digital cameras are now used by many professional photographers for weddings and other events. Many newspapers and magazines are now employing digital photography, which bypasses the darkroom, and allows the input of images directly to editors. For home users, digital cameras range from very inexpensive (under $30, often before rebates) point and shoot models to sophisticated models that rival 35mm SLR cameras, including accessory lenses and peripherals.
The potential resolution of digital cameras is measured in "pixels", a condensed term for "picture elements". Pixels are basically the little colored dots that compose an image. More pixels in an image mean that a larger size picture can be printed or viewed, but increases the amount of storage or memory necessary to hold the image. Contrary to popular belief, more pixels are not necessarily better. Consider that a typical 14" monitor has a resolution of 640x480 pixels, which is about 300,000 pixels. The unedited image from a digital camera with a 300,000-pixel resolution will fill the screen of that 14" monitor. My 17" monitor is currently set at a 1024x768 resolution; a digital photograph of about 740,000 pixels would fill that screen. Many digital photographers take their photos at the highest resolution, which is often unnecessary, and a waste of memory and time. If the image is to be emailed, or posted to the web, the image will likely have to be substantially reduced in size to be practical. Using good quality photo paper and a photo-grade color printer, an 11x14" image will require about 4 million pixels (4Mp) to approximate the quality of a 35mm print. An 8x10 inch print will require about 2Mp. An inexpensive 1Mp camera is quite capable of producing satisfactory 5x7 inch photos. The least expensive cameras on the market, sometimes under $20 (I recently paid $19 for one), can easily produce a printed picture in the common 35mm print size of 3.5x5" or 4x6" sizes. Some digital cameras, such as one of the Olympus CamMedia series, can print directly from the camera, using Polaroid film, or conventionally export images to a computer.
Digital cameras need something to hold the images until they are transferred to a computer, or printed directly on a capable printer. Various types of non-volatile memory cards – Compact Flash, Smart Media, or memory stick formats – are used to store images. Currently, these cards are available in capacities of up to 1GB (about 1 billion bytes), with 16MB to 128MB being common and relatively inexpensive. The images are typically transferred via a USB connection, or read directly by a card reader.
Other popular cameras, such as some of the Sony Mavica series, use common 3.5" floppy disks. These floppies, each holding about 1.4MB, are in standard PC format. Some advanced (and expensive) digital cameras can write to mini-CD discs, which can hold well over 100 megabytes, and can be read on any CD drive. Generally, the more storage of any type available in a camera, the better.
Many digital cameras also have the ability to record short movies, sometimes with sound. The length of the movie is only limited by the memory available in the camera. For most common movie capable digital cameras, the length is typically measured in seconds.
Zoom is another camera feature often available. With traditional film cameras, optical zoom is used. The zoom on digital cameras can be optical, digital, or both. In terms of image quality, optical zoom is superior to digital zoom. One digital camera I tried is advertised as having a 20x zoom; 4x optical, and 5x digital. At 20x (combining the digital and optical zoom), the images were quite grainy, but at 4x (optical) they were very sharp. The same image at 4x digital zoom was visibly grainy, especially when enlarged. If a choice is available, optical zoom is superior to digital zoom.
Convenience factors, such as size, weight, flash, and battery capacity are often a matter of personal choice. Many cameras use common AA size batteries for convenience. These alkaline batteries become expensive if many pictures are taken as they have a short useful life in cameras. Rechargeable Nickel Metal Hydride (NiMH) batteries are much more expensive to purchase, but the better ones have a capacity of two to four times the photos as alkaline batteries, and can be recharged around 1000 times. In the long run, NiMH batteries are far cheaper to use than alkaline. Select the NiMH batteries by comparing their capacity, typically 1200 to 1800 mAh (milliamp hours), the more the better.
Another factor is the viewfinder. Many digital cameras have a conventional lens type viewfinder, while others have an LCD screen that gives you a "what you see is what you get" view. Some cameras have both. Many users have found that it is harder to aim a digital camera using an LCD screen than a viewfinder, but others prefer to see the exact picture on the LCD an instant before the image is captured. Almost all cameras come with an integral flash or some sort of "hot shoe" for an external flash. Some digital cameras combine their still function with a live video function, as they can also serve as webcams, sending live video over the net.
Digital photography can be both a money and time saver for many users, and should be strongly considered for that next camera purchase.
