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How Cameras Work

A short insight into the DSLR and how it works

How Cameras Work

How Cameras Work and Taking Control - This is a very important aspect of photography, knowing all about and taking control of your camera. It is all too easy to become bewildered, worried and confused by all of the bits, buttons and features that your camera has to offer.

Don't ever feel that you have to use them all, because you don't!

A suggestion however, is that over time you learn what each feature does so you know what works for you. Simply read the manual at your own pace (I know how complex they can be). Just sit and play with the camera on all of its settings. Take shots in different modes, try different white balance settings and see the changes, try some custom functions too.

The more you learn about the equipment that you use the more confident and comfortable you will become when out photographing. It is a great feeling to be able to switch modes, lenses and settings in an instant. SO you can match the subject you are shooting.

How Cameras Work - The SLR camera in a nutshell!

The basic principle of capturing light to make a permanent image has not changed for hundreds of years. Artists from centuries ago used a simple, one element lens to throw a reversed and flipped image onto a piece of paper. This enabled them to trace the outline of a subject that they wished to paint.

This is how some of the oldest paintings are so incredibly accurate with regards to composition and proportions. As a child, did you ever paint people with excessively large hands or small heads? It is difficult to judge perspective, but when using the above methods, you cannot go wrong.

The DSLR camera is no different. The light passing through the lens is flipped and reversed in the same way and firstly projected onto the focussing screen via the mirror. This enables you to see what will be recorded and make adjustments to the focussing and composition.

See the image at the top of this page (click for larger version).

When you take the shot:

  • The mirror is lifted
  • The shutter opens
  • Light hits the sensor at the back of the camera

The distance from the rear of the lens to the focussing screen (when bounced from the mirror) is exactly the same as the distance from the lens to the sensor. This is necessary to be able to "shoot what you see".

Quite simply, if you focus, compose and expose your subject well, that is all you need for a good shot! In a nutshell, most of the features of modern Digital SLR's could be redundant. They are there to increase speed, efficiency and to satisfy our desire for gadgetry, technology and sometimes, laziness.

As proof, take your camera outside and try this:

  • 1
    If you have a tripod, use it
  • 2
    Set the camera to fully manual
  • 3
    Set the lens to manual focus
  • 4
    Line up the shot
  • 5
    Focus carefully
  • 6
    Use the camera's built in light meter to set the shutter speed and aperture correctly
  • 7
    Adjust the aperture and shutter speed until the bar is in the center (that means the exposure is correct
  • 8
    Take the shot

Now switch the camera to Program mode or fully auto including focussing. Take another shot and have a look at them both. Apart from varying depth of field due to aperture fluctuations, the images should be practically identical. Many people, including myself as a youngster, mistakenly think that "Fully Auto" means better pictures.

My point is that it is not important to get caught up with all the latest updates, upgrades and features. What you should really be doing is improving your "eye" and the basic principles of how cameras work. Your ability to see a great shot, capture it well and process it to perfection are more important than all the technical jargon that is widespread nowadays.

Henri Cartier-Bresson

One of the most famous photographers of our time, who sadly died in 2004, was Henri Cartier-Bresson. He mainly used a simple 35mm camera with a standard 50mm lens and very little else.

No filters, no matrix metering, no 45-point autofocus and no Photoshopping. Just a keen eye.

Of course, in the real world, we all crave knowledge and understanding. It is sometimes necessary to know how the modern cameras function and how to put their features to best use. Especially in a more professional capacity when time and perfection are of the essence. That is where this book comes in.

In my opinion, it doesn't matter how an image was created. If it looks good, it looks good but everyone is different and has different tastes, styles and techniques. This brings me back to my original point. Learn the functions and features of your equipment, find what "works for you" and get out and enjoy yourself!

Final Thoughts

Just for your information, the settings that I personally use 95% of the time for stills are these:

  • Focussing - Auto, centre-point only, one shot (Servo sometimes for sports). See Chapter 11.
  • Metering - Evaluative. I.e. an average of the whole scene. I use exposure lock on many occasions to make any necessary adjustments. See Chapter 4.
  • Mode - Av/Aperture Priority, Tv/Shutter Priority or Manual. For much of the work I do, I would rather have control over the depth of field than the shutter speed. If I need a fast speed, I simply whack open the aperture to the largest to give the fastest possible shutter speed. Although on occasion, it is good to be in control of the shutter (sports/wildlife etc). See Chapter 10.
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    ISO - 100 to 800. Nowadays the difference is barely noticeable. Have used up to 6400 on occasions.

These chop and change depending on what and where I shoot but are the general settings I tend to use.

Experiment with different set ups to find what is good for you and your style of photography. All the practising "sinks in" over time and you will have a much better understanding of your equipment and how it works.

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