Saturday, January 20, 2007

advantages and disadvantages

Advantages of professional digital cameras

Image recycles every 3 seconds from before to after image.
Image recycles every 3 seconds from before to after image.
  • Immediate image review and deletion is possible; lighting and composition can be assessed immediately which ultimately conserves storage space.
  • The ability to shoot in RAW format (images that contain tagged data directly from the sensor). However, as of this writing, there are a number of proprietary RAW formats, some of which require specific software to manipulate.
  • Faster workflow: Management (colour and file), manipulation and printing tools are more versatile than conventional film processes. However, batch processing of RAW files can be time consuming, even on a fast computer.
  • Digital manipulation: A digital image can be modified and manipulated much easier and faster than with traditional negative and print methods. The digital image to the right was captured in RAW format, processed and output in 3 different ways from the source RAW file, then merged and further processed for color saturation and other special effects to produce a more dramatic result than was originally captured with the RAW image.

Recent manufacturers such as Nikon and Canon have promoted the adoption of digital Single-lens reflex cameras (dSLRs) by photojournalists. Images captured at 2+ megapixels are deemed to be of sufficient quality for small images in newspaper or magazine reproduction. Six to 14 megapixel images, found in modern digital SLRs, when combined with high-end lenses, can approximate the detail of film prints taken with 35 mm film based SLRs, and the latest 16 megapixel models can produce astoundingly detailed images which are believed to be better than 35mm film images and the majority of medium format cameras. [1]

[edit] Disadvantages of digital cameras

  • Some consider the picture quality of pictures taken on film cameras to exceed that of digital pictures.
  • Some film cameras operate without batteries, as the image is stored on film rather in memory using CCD/CMOS sensors and associated electronics which require power to operate.
  • There are special types of film, such as for infrared light, that have no equivalent in commercially available digital (CCDs are sensitive to near infrared). Some digital cameras may be converted to be highly sensitive to infrared light, while other cameras can use a special filter over the lens to block available light, and make an image with only infrared (this often requires a very long exposure).
  • Film remains more admissible as evidence in court [citation needed], as it is much harder to manipulate than digital [citation needed].
  • Film has a better dynamic range. However, some newer CCDs such as Fuji's Super CCD, which combines diodes of different sensitivity, have addressed this problem. Also, software measures that selectively expose darker pixels longer exist, and could potentially enable digital cameras with infinite dynamic range.
  • Film are available in different sizes 35mm, half-format, full-format etc and the later may under right conditions generate images with higher spatial resolution.

For most consumers in prosperous countries such as the United States and Western Europe, the advantages of digital cameras outweigh their disadvantages. However, the professional photography community is split on the issue. Much of the post-shooting work once done in the past by a photo lab is now done by the photographer himself. Problems some professional photographers have voiced include: editing and post-processing of RAW files can take longer than 35mm film, downloading a large number of images to a computer can take away from valuable shooting time, shooting in remote sites requires the photographer to carry a number of batteries and add to the load she/he must carry, all cameras break from time to time — film cameras can often be fixed on the spot but digital cameras often can not. As time passes, it is expected that more professional photographers will switch to digital.

[edit] Equivalent features

  • Image noise / grain: Noise in a digital camera's image is remarkably similar to Film grain in a film camera. At high ISO levels (film speed) the grain/noise becomes more apparent in the final image. Although film ISO levels can be lower than digital ISO levels (25 and 50 respectively), digital settings can be changed quickly according to requirements, while film must be physically replaced and protected from all light during such replacement. Additionally, image noise reduction techniques can be used to remove noise from digital images and film grain is fixed. From an artistic point of view, film grain and image noise may be desirable when creating a specific mood for an image. Modern digital cameras have comparable noise/grain at the same ISO as film cameras. Some digital cameras though, do exhibit a pattern in the digital noise which is not found on film.
  • Speed of use: Current digital and film cameras can be switched on and take images instantly. Saving images to disk takes no longer than winding on the film (see Frames per second).
  • Frames per second: The Canon EOS-1D Mark II N can achieve 8.5 frames per second which makes it the fastest digital SLR in the world; the fastest film SLR could shoot 10 frames per second. The Nikon F5 is limited to 36 continuous frames (the length of the film) while the Nikon D2H is able to take 40 images before its buffer must be cleared and the remaining space on the storage media can be used.
  • Image longevity: Although digital image data does not degrade (film stock can fade), the media on which the digital images are stored can decay or become corrupt, leading to a loss of image integrity. Both formats should be stored under archival conditions for maximum longevity. Perfect copies of digital images can be made on fresh media, and digital images can be stored on duplicate media. This greatly reduces the risk of losing digital images, and if done correctly, digital backups are safer than film. In comparison, copying negatives or transparencies incurs additional noise and loss of detail. Negatives can however be easily converted to digital if longevity is a requirement.
  • Colour reproduction: Colour reproduction (gamut) is dependent on the type of film / sensor used and the quality of the capture media, lens group and processing. Different films and sensors are sensitive to differing subsets of colour thus the photographer needs to have an understanding of the light conditions and the media used to ensure accurate colour reproduction. Many digital cameras offer RAW format (sensor data) which makes it possible to choose color space in the development stage regardless of camera settings.

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