Visual content	Issues for visual content	Image production	Image acquisition	Image manipulation	Image creation

Digital cameras allow you to take images directly from the camera to your computer, and they are becoming more affordable. There are many advantages, but also some disadvantages in using a digital camera.

Digital cameras can be enormously useful in acquiring images for web use, however there are some major considerations in using this method:

Advantages

• The convenience of web-ready images with no film processing or scanning
• White balance ­ the colour balance can be adjusted to any light source, even mixed sources (such as daylight + fluoro), without the need for special film, filters or colour correction in printing.
• Dynamic range ­ the ability to retain detail in shadows and highlights, particularly in cameras with 16-bit/channel capability.
• Archives, if properly set up and managed, can be searchable, widely accessible databases.
  

Disadvantages

• Resolution - the size and resolution of the image is generally extremely limited because of the limited data storage space. Even models that allow you to take a relatively high-resolution image will store a very limited number of these images, will operate very slowly when taking these images, and will use a lot of battery power in doing so. The resolution is usually quite adequate for web use, but not very useful if you also wish to print the images.
• Compression - while there are usually a range of options for image size, many of these relate to the degree of JPEG compression. As has been discussed (Image compression), this is a lossy format, with greater loss of image quality as the amount of compression increases. Camera options that allow, for instance, 30 images on a floppy disk, will produce severely degraded images. It is recommended to take pictures with either no compression, or the minimum compression setting.
• Optical quality - while the quality/price ratio of digital cameras is constantly improving, those cameras aimed at the domestic market (under $1000) have fairly limited optical quality ­ comparable to a 'point & click' viewfinder camera, nowhere near the lens quality of a brand-name 35mm SLR camera.
  

Given the limitations of resolution, compression and image quality, a 35mm negative or transparency will give you an image of significantly higher quality, which is arguably easier to archive. The advantages and disadvantages should be weighed against the particular purpose for which you are using the images.

Operating a digital camera

Digital cameras vary considerably in their control layout and operation, but generally have fairly limited options.

Settings you will need to be aware of that would be different from using a film camera include:

• Set image size and compression (usually 4-6 options)
• Set colour balance
• Ensure adequate battery life (batteries are fairly quickly exhausted)

Using a digital camera is more similar to using a 'point & click' viewfinder camera than using a manual control SLR camera.

For most mid-range digital cameras

• There is no adjustable light reading ­ there is either enough light, or not enough in which case the built-in flash will intervene. It is possible to set exposure against a particular focal point of the image. It is not possible to use remote flash lighting.
• It is not possible to determine either the lens aperture or the shutter speed, making control over depth of field or motion blur difficult.
• Focus is automatic, which delays the response between selecting your subject, focusing, and triggering the shutter. Focusing can be set to use a particular point rather than just the central point of the image.
• The 'shutter' is not mechanical, and is therefore disconcertingly quiet ­ it can be difficult to tell if it has actually responded.

More expensive, professional models allow a much greater degree of control to the user, and can accommodate interchangeable lenses, remote flash etc. Some 'professional' functions such as manual setting of aperture and shutter speed are now becoming available in the more expensive domestic models.

The images saved to the camera can be downloaded directly to your computer's hard disk via a cable connection (generally USB). Most cameras save images to removable media (memory card, memory stick, floppy disk etc), which can be exchanged as they become filled with images.

Summary

• Advantages of using a digital camera include: convenience, auto colour balance, shadow/highlight detail, useful for image databases.
• Disadvantages include: low image quality (resolution, compression and optical), less control than with an SLR, slow operation and short battery life.
• Professional models have better quality and functionality than 'domestic' models.
• The images, which are usually saved to a memory card or disk, can be downloaded directly to your computer.