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Digital Cameras - the Digital Single Lens Reflex Camera (DSLR)

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Digital Cameras
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What is a Digital Single Lens Reflex Camera (DSLR)? The single lens is easy to explain - the camera is equipped with only one lens1. However the major benefit of this type of camera is that the lens is interchangeable. There is huge variety of lenses available ranging from the wide angle to extreme telephoto. This gives the user vast creative scope. However, this does come at a price and puts this type of camera in the expensive end of the hobby. Although the DSLR offers several pre-programmed modes (essentially point and click), the user has full control of all three of the operations of the camera, focus, shutter speed and aperture. This will allow the user a vast creative scope only limited by equipment or experience.

Single Lens

An SLR's operation is essentially the same as that of any other digital camera, where the lens simply projects the image on to the camera's sensor and the picture is created by a click of the shutter. The main difference is the photographer uses the viewfinder to see through the camera's lens when composing a photograph. There is a mirror positioned between the lens and the image sensor that directs the image up into a second mirror, which is lined up with the eyepiece of the viewfinder.


This is where the reflex part of the mechanism comes in. When a photograph is taken, the mirror is mechanically lifted to allow the picture to be exposed on to the film or the image sensor. The action is similar to the reaction that occurs when a doctor tests the reflex in the leg. As the mirror starts and returns to the same place you are always ready for the next shot.

The beauty of this system is that it allows the photographer to see a true image in the viewfinder of the subject in the photograph - a proper lens-eye view.

There is also a huge array of lenses, accessories and attachments available to the SLR user. The main reason for this is that SLRs have been around since even before the era of 35mm film, so the system is well established. The Digital SLR is a modification of the image reproduction system, not the camera.

The Digital SLR is capable of producing superb results, not because it has a better imaging system than other cameras, but simply because of the variety of lenses available. The sheer variety and quality is astounding and this gives the DSLR the edge for the serious hobby and professional photographer. It comes at a price as a serious SLR and two or three lenses can cost over £4,5002 and they can be quite inconvenient to carry around3.

If you are on a budget, don't despair - the used bargains are out there. Don't forget that cameras are pampered possessions so a pre-owned camera is normally in excellent condition. If you want a warranty and technical support it is advisable to buy from an established used camera dealer.

Good Points

They have the ability to allow you to change lenses. The cameras can even be attached to some microscopes or astronomical telescopes.

A benefit of a digital imaging system is an increase in the Frames Per Second or FPS rate. This makes it easier for anyone to take good fast action and nature photographs. This type of camera will challenge you and you will enjoy using one.

They are more sophisticated than most Digital Compact Cameras and share functionality with Digital Bridge Cameras in that they allow the use of additional filters and complex flash units. They are commonly programmed with photographic filters and techniques such as panorama, plus camera effects such as Pop Colour4.

As with Bridge Cameras, DSLRs are so easy to use they can encourage lazy photography. That is not a problem as a novice can achieve good results from the start. A skillful photographer, however, can get some superb results. But remember to try and 'see' the photograph in your mind's eye before you pick up the camera. All this means you will get good results and not find yourself disappointed with this type of camera.


They often have video capability. This is a mixed blessing as the results are often disappointing. If you use the video option, don't make the two big mistakes. The first is zooming whilst filming - it can result in a poor quality film, and moviemakers seldom use it (remember almost all cameras will make some noise on the soundtrack of your video). The second is not using a tripod when filming, which can lead to you producing blurred and unstable images.

Even small memory cards now can hold over 1,000 images - this freedom will encourage creative experimentation and that will inevitably improve you as a photographer. However, regular downloading and editing is advisable to keep track of your work.

Getting prints produced can be expensive, but at least you don't have to print every image to see your results. If you take a lot of photographs it is an idea to invest in a decent printer.

Before you purchase a DSLR, make sure the few benefits it has over the Digital Bridge Camera is worth it to you. General image quality will be very similar unless you buy a poor quality camera.

Common Features

  • Autofocus
  • Auto exposure
  • Auto power off
  • Ability to change lenses
  • Built-in flash
  • Tripod mount
  • Rechargeable battery supplied with charger
  • The camera will tag the time and date on all images
  • Geotag on some cameras

Geotag can be very useful if you travel a lot and do not download your photos very often, so do ask when considering a purchase. Some cameras now have the ability to connect to your smartphone or tablet. This lets you remotely control your camera and see the viewfinder image, allowing you to press the remote shutter at the right time.

A few makers of DSLRs, representative of the range available from non-specialist stores, include:

  • Canon
  • FujiFilm
  • Leica
  • Nikon
  • Olympus
  • Panasonic
  • Pentax
  • Rollei
  • Samsung
  • Sony
  • Yashica

Important Tips and Notes

  • If you take large numbers of photographs, create photo bookmarks - after the session write the date, location and details of the day's work on a sheet of paper, then take a photo of the paper to record the information. It saves all the bother of remembering to carry a diary with your camera to record each shot's details and means the information is attached to the day's work rather than being separate and easy to lose.
  • Just in case you need reminding, take care when pointing the camera at the Sun as it may damage your eyes and the camera.
  • If the camera does not come with a case, buy a good one - you will never regret it. Besides giving protection, they keep the dust off.
  • Buy large memory cards, but not too large as you have to find your images later. Several smaller ones are more useful - buy different cards from good makers so you can more easily distinguish between them and identify the contents.
  • It is unwise to only store photos on your PC as it might malfunction. You can store them on an external hard drive (HDD) but file them with care so you can find them later.
  • If you take a lot of photographs, edit them ruthlessly - delete duplicates and any that are out of focus. File them by subject, year and month. File events such as holidays, weddings, etc, separately.
1Yes there is/was a twin lens camera. The Twin-lens Rolleiflex III Camera is iconic, with two lenses set one above the other and linked focus control. The top one you look through to focus and the lower one focuses the image on the film.2Important Note - as technology moves so rapidly, this may only be current for a few years.3And even then the quality of images produced by DSLR cameras is eclipsed by images from medium format cameras, which contain larger film or digital sensors and so capture better results. Unfortunately a basic Bronica ETR digital system is in excess of £10,000 - seriously expensive and a little awkward for general photography as the cameras are correspondingly larger to contain the larger sensor.4Pop Colour is a black-and-white image with only one of the primary colours included in the image

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