This tutorial examines the use of digital cameras. It covers the advantages, limitations, and ways to use digital cameras, their operation, types, resolution, available features, and tips for taking better photographs. It also looks at photo-quality printers, in terms of important features for digital printing, and types of paper that are available for this use.

Digital Camera Basics

Digital cameras allow users to take photographs and store the photographs digitally, instead of on traditional film. Many digital cameras allow users to review and edit images while they are still in the camera. All digital images can be downloaded to computers for editing in various photo-editing software programs.

Advantages of using a digital camera:

  • Digital images taken by a digital camera are instantly available and usable. As soon as you take a digital photograph, you can use it.
  • You can tell as soon as you take a picture whether or not you got the shot you wanted. If not, you can take more shots until you get the ones you want.
  • Digital images are immediately ready to be used on the Internet.
  • You can delete bad shots and keep only the good ones before they are printed, so there is no cost for bad photographs.
  • Digital images can easily be sized however you want.
  • Digital images can be used in many ways including for printed photographs, web sites, printed publications, and e-mail attachments.
  • Digital images can be easily stored on hard drives, CD-ROMs, and Zip disks.

Ways to use a digital camera:

  • Use digital images in slide shows, screen savers, and photo albums.
  • Print digital images on specialty papers such as photo-quality paper, labels, business cards, fabric transfer papers, greeting cards, fine-art papers, etc.
  • Use digital images in documents created by various types of software programs such as desktop-publishing programs, word processing programs, spreadsheet programs, and database programs.
  • Post digital images on the internet.
  • Send digital images via the Internet to professional printers for professional print jobs.
  • The quality of digital photographs depends on many variables.

Digital picture quality depends on:

  • The camera user's photography skills.
  • The optical quality of camera lenses.
  • Pixel resolution (1-megapixel, 2-megapixel, 3-megapixel, etc.).
  • Camera features used to adjust picture quality, such as zooming, balance, and special effects.
  • Type of file format (JPEG, TIFF, proprietary format, etc.).
  • Level and quality of image file compression used.
  • Image editing software used.
  • Print size.
  • Printer type and quality.
  • Paper quality.

Digital Camera Operation

When digital photographs are taken, digital cameras produce a digital file that is stored on a small magnetic storage media, similar to what is used by computers. Digital cameras require storage space on a hard drive, CD-ROM, zip disk, or floppy diskette after photographs are downloaded from a camera.

When the shutter of a digital camera is pressed, light passes through the lens of the camera and the image is focused on a chip called a charge-coupled device (CCD). The CCD generates an analog signal composed of the image. The analog signal (DSP) is converted to a digital signal by an analog-to-digital converter (ADC). A signal processor (DSP) adjusts the quality of the image and stores the digital image on storage media (floppy disk, compact flash card, PC Card, memory stick, microdrive, SuperDisk, etc.) in the camera. The images are then ready to be transferred to a computer.

A digital camera can be plugged into a computer for image transfer or removable media, such as a disk, can be removed from the camera and attached to a computer for image transfer. Most digital cameras have a television-like liquid crystal display (LCD) that users utilize to compose their shots. Since digital cameras do not use film, images can be viewed immediately after they are taken on the LCD. Users can immediately delete shots they do not want to keep.

This compares with traditional cameras that use film coated with light sensitive chemicals to capture and store an image. When light hits the coated film, a chemical reaction occurs and the image is stored on the film. This film has to be chemically processed for development. Physical prints of the prints are made and may be stored in the form of negatives.

Limitations of Digital Cameras

  • Quality digital cameras generally cost a lot more than comparable traditional cameras.
  • Generally, image quality may not be as good as that of traditional cameras and the size of photograph enlargements may be limited by the digital camera's resolution.
  • Good quality prints of digital photographs require cameras that shoot at higher resolutions. These higher-resolution digital cameras are expensive.
  • Digital cameras eat batteries, so they constantly need to be replaced or recharged.
  • Digital cameras capture images in two ways, either using static array or linear array. Using static array, the CCD captures the image in one fast exposure, while using linear array, the CCD captures the image using a longer scanning exposure. This means linear array cameras are only suitable for still life shots.
  • It can be difficult to see a liquid crystal display (LCD) in bright sunlight.

Types of Digital Cameras

Digital camera features, size, shape, and cost vary greatly between manufacturers and models of digital cameras. There are now over 250 models on the market. Some have very few features and others have more than 100 features. Many of these features allow you to do things that are not possible with traditional cameras such as adjust white balance for varying lighting conditions, increase brightness, and create special effects like sepia (golden brown) tones.

There are five basic types of digital cameras:

  • Beginner digital cameras - Beginner cameras are simple, point-and-shoot devices with few special features. They have a fixed lens (with no special capabilities, such as focus and zoom), a simple optical viewfinder (no LCD viewfinder), and built in memory (no removable memory cards. Resolution is from 640-by-480 (VGA) to 1,024-by-768 (XGA). These cameras are designed for people on tight budgets, those who want point-and-shoot capabilities, and want only snapshot-size prints. Prices generally range from $79 to $200.
  • Consumer digital cameras - Consumer-level digital cameras have more features than beginner cameras, but are still fairly simple to shoot. They usually have an auto-focus lens and some have a zoom lens. Consumer-level cameras have LCD viewfinders and removable memory cards. Additional features may include different flash modes, white balance, video out, and various modes for photographing for special effects such as shooting black-and-white or sepia (golden brown toned) photographs. These cameras are for those who want better image quality than beginner cameras and who want to print larger prints. Most have 1 to 2.2-megapixel resolution. Prices generally range from $200 to $500.
  • Advanced consumer digital cameras - Advanced consumer-level cameras have a long list of features, great picture quality, or a combination of both. Most have excellent auto-focus zoom lenses, many program modes for special effects, image enhancements (such as flash adjustment and color, contrast, and brightness controls), and special features (such as wireless remote control, time lapse, and manual focus). These cameras are for those who want photo-quality enlargements, many image controls, and a wide range of features and functions. Most of these cameras have 3.3-megapixel resolution. Prices generally range from $500 to $900.
  • Prosumer digital cameras - Prosumer cameras are designed for serious photographers only. They concentrate on precise control, fast operations, and superior image quality. Prosumer lenses are not interchangeable like professional models and the image sensors are less sophisticated. These cameras are for those who want near-film-like performance and image quality, top-quality zoom, and extensive manual controls. These cameras have between 3 and 5-megapixel resolution. Prices generally range from $1,100 to $2,000.
  • Professional digital cameras - Professional cameras have sophisticated image sensors that can produce photographs that are indistinguishable (or even better) than film. They have a wide range of controls that allow the user to have control over every aspect of the photograph. Professional cameras are for those who want to use multiple lens, true film-like performance and image quality, total manual control, and price is not an issue. These cameras have between 3 to 6-megapixel resolution. Prices generally range from $4,000 to $15,000.

Digital Camera Resolution

The quality of digital cameras is typically judged by their resolution. Digital camera resolutions are commonly expressed as the number of pixels per inch it can capture. A pixel (picture element) is the smallest point of a bitmapped screen that can independently be assigned color and intensity. Digital pictures are made up of many pixels of varying color and intensity, similar to the way a mosaic is made up of many different colored tiles.

The pixel resolution of a digital camera determines the pixel resolution of the photographs it takes. The total pixel resolution of a photograph determines the maximum size of a quality print that can be made using that file. Once the photograph is taken and the pixels have been captured, the pixel-per-inch value can be changed. The greater the resolution (or pixels per inch), the larger the file will be.

Digital Camera Resolution and Maximum Print Size:

Resolution per inch -- Maximum desktop print size (inches)

VGA (640-x-480) -- 3.5 x 5-inches

1-megapixel -- 5 x 7-inches

2-megapixel -- 8 x 10-inches

3-megapixel -- 11 x 14-inches

4-megapixel -- 14 x 17-inches

5-megapixel -- 16 x 20-inches

Digital Camera Features

Some available digital camera features:

  • Point-and-shoot (fixed focus) or auto-focus - Some digital cameras come with a point-and shoot feature that attempts to focus everything in the image for the user. Other digital cameras have an auto-focus feature that gives the user some control over the focus. Auto-focus cameras generally produce a better-quality image.
  • Lens focal length and speed - Focal length controls the magnification and the angle of the view that can be taken with a lens. Lenses can be wide-angle, normal, telephoto, and zoom. Lens speed determines how much light is required to take a photograph. Fast lens speeds are better for taking photographs in low light areas.
  • Optical versus digital zoom capabilities - Optical zoom allows a user to zoom in on an object by using the lenses. Digital zoom allows zooming through the use of software. Optical zoom creates much better images than digital zoom.
  • Macro capabilities - Allow the user to take close-up images.
  • Viewfinder and/or LCD - A viewfinder is an optical window that allows the user to point the camera, but it does not accurately represent the image that is being taken. A liquid crystal display (LCD) is a television-like screen that shows what the picture will look like. Some cameras have viewfinders, others have LCDs, and still others have both.
  • Image storage media (CompactFlash, SmartMedia, floppy disk, or other) - Various types of cameras use various types of storage media for the storage of digital images. CompactFlash and SmartMedia are the most common and have the most storage capacity. They come in various sizes ranging from 4 MB to over 300 MB.
  • Type of interface between the personal computer and digital camera (generally, serial or USB) - The interface is what enables the user to connect a digital camera directly to a personal computer in order to transfer digital images. The serial cable interface, where a cable connected to a camera plugs into the serial port of a computer, is by far the slowest. The Universal Bus (USB) interface, where a USB cable connected to a camera plugs into the USB port of a computer, is much faster. (Note: Not all computers and operating systems support USB interfaces.)
  • Image file format, file compression options, and capacity - Digital camera makers offer a variety of file format options and compression technologies, which affect a digital camera's capacity to store images. Different formats have an impact on the quality and capacity of files to be used by various photo-editing software.
  • Flash capabilities - Digital cameras come with a variety of flash capabilities.
  • Capability to add lenses - Some digital cameras allow for the use of telephoto and/or wide-angle lenses and others do not.
  • Capability to output to a television - Some digital cameras allow users to connect their camera directly to a television screen by using a cable that plugs into the VIDEO IN port on the television or VCR. Often cameras that have this feature also have slide show capabilities.

Digital Camera Tips and Techniques

Learning How to Use a Digital Camera

Several digital camera manufacturers now offer free online courses to teach users how to use specific digital cameras, including Kodak (http://www.kodak.com).

Kodak has an online Digital Learning Center at their web site (http://www.kodak.com) that has wonderful free online photography courses including one called Kodak's Guide to Better Pictures. Canon has several tutorials containing photograph-taking tips at their web site (http://www.canongallery.com/)

Tips for Taking Better Photographs:

  • Carefully position the camera and the view for the photograph
  • Shoot with the best possible light
  • Hold the camera steady
  • Use the flash in shaded areas
  • Use a simple background
  • Balance the shot
  • Place the primary object off-center
  • Add a frame for interest
  • Try shooting from different perspectives
  • Use color for capturing attention

Printing Digital Images

Photo Quality Printers

Digital camera users generally want the capability to print their digital images in their home or office. Many types of photo-quality printers are available to allow them to do this. Some produce excellent quality prints and others produce prints that are not so good. Prices range from $100 to more than $1,500. Current reviews of photo-quality printers can be found at the PC Magazine web site (http://www.pcmag.com) and at the PC World magazine web site (http://www.pcworld.com).

Important photo-quality printer features for printing digital images:

  • Print quality - Print quality is the most important feature for a photo-quality printer. A good photo-quality printer will produce even, continuous gradations, and will not show any banding (straight lines across the printer head path). Colors should be correct and not faded. Overall, the appearance of prints of photographs should be close to the way the photographs appear on a computer screen.
  • Print resolution - Print resolution is specified in dots-per-inch (dpi). Printers with higher dpi generally print better images than printers with lower dpi. Dpi affects the sharpness of the image, the smoothness of the gradations, the details of highlights, and the darkness of shadows. Inkjet printers with 300 dpi or more are capable of printing a good photo-quality print.
  • Maximum print size - Most standard photo-quality printers can print photographs up to 8 x 10 inches in size. Photographs 8 x 10 inches and larger require huge image files. An uncompressed 8 x 10-inch color image formatted at 300 dpi can create a file size of 21.6 MB and an 11 x 14-inch image can create a file size of 41.6 MB. Keep in mind the limitations of the processing power and storage space of a system.
  • Adjustable printer head height - Some printers, including many of the more expensive Epson printers, allow for the printer head to be raised to accommodate thicker fine-art papers, such as watercolor paper or artist canvas.
  • Paper-feed path - Printers that enable thick paper to feed straight into a printer (rather than a fed that makes paper turn around a narrow-diameter roller) allow for the use of thicker papers and will give better results.
  • Print speed - Print speed can be important when printing more than a few prints. Generally, photo-quality printers are fairly slow, because they are optimized for quality, not speed.
  • Ink cartridges and print heads - Inkjet printers can be expensive to use. Print cartridges can run from $15 to $40, depending on the brand and model. Full-page prints use a lot of ink. Be aware of how ink cartridges for particular printers are sold. Some printers require a black cartridge and a separate color cartridge. (Users replace the black cartridge when the black ink runs out and the color when the color cartridge runs out.) Others require a single cartridge (black and other colors all in one-if one color runs out the entire cartridge must be replaced). Still others require cartridges for four different colors. The type of printer usage can greatly impact the number of cartridges used. For example, if printing a lot of black and white photographs, printing on the printer with the separate black cartridge would be less costly.

Paper for Printing Digital Images

The paper you choose for printing digital images has a major impact on the overall quality of your print. Types of paper for printing digital images:

  • Standard ink-jet paper - Use standard printer paper for draft or test work, then print on higher quality paper. Standard ink-jet papers do not have the weight (thickness) or sufficient surface quality for printing digital images.
  • High-quality non-glossy papers - High-quality non-glossy papers allow for better printing quality than standard ink-jet paper. They are thicker than standard paper and have a non-glossy surface. Use this type of paper for printed publications.
  • Photographic papers - Several good-quality photo-grade papers are available for use with ink-jet printers, including many sold by Kodak and Hewlett Packard. Many weights (thicknesses) are available. The paper weight, designated in pounds, is shown on the boxes of paper. The greater the weight, the thicker the paper.
  • Fine art papers - Fine art papers, such as watercolor papers, canvas papers, textured papers, and other papers that create special effects during printing are available for ink-jet printers. The special effects papers can be used in conjunction with special effects created in photo-editing software.
  • Specialty papers - Specialty papers are available for the printing of greeting cards, business cards, labels, stickers, transparencies, fabric transfers, CD labels, jigsaw puzzles, etc.

CD labels
http://www.neato.com

Ink-jet standard and photo-quality papers
http://www.officedepot.com
http://www.officemax.com
http://www.bestbuy.com

Online digital photography training
http://www.kodak.com

Cohen, S. and Williams, R. (1999). The Non-Designer's Scan and Print Book, Peachpit Press, Berkley,CA.

Marmel, E. (2001). Teach yourself visually digital photography, Hungry Minds, New York, NY.

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