© 2010 - 2012 Photography Art Cafe. All Rights Reserved.
Digital Camera Basics
So we've taken a look at the 4 main types of cameras in part 1 of this series. The purpose of this tutorial is to give you a whistle-stop tour of 10 key areas of digital photography/cameras, plus some takeaway lessons. This is an introduction to the basic facts about digital cameras, how they work, why certain bits matter and what it all means for your photography. The practical tips that follow this tutorial will make a lot more sense once you've got to grips with these simple facts...
1. How cameras capture light
In a nutshell, all cameras work by admitting a small amount of light into an otherwise lightproof box, via a little hole, which is then projected on to some kind of light sensitive surface at the back of the box, forming an image.
That, in effect, is a pretty fair description of something called a pin-hole camera. These are such simple devices that you or I could make one! One key feature that you'll notice if you use a pinhole camera is that the image created appears upside down and left to right. Why is that...?
Well, it's because light only travels in straight lines. So, light from high up in the scene we are photographing projects downwards through the hole in our camera and is recorded at the very bottom of the light sensitive surface.
Make a fist with your hand, leaving a tiny hole to see through. Now peer through the hole and try to see as high up as you can. You moved your head lower didn't you? That's because the light moves in a straight line, from high to low. The same goes with light travelling from left to right.
The pictures we take with our modern digital cameras are also inverted in this way. Another interesting fact about pinhole cameras is that the smaller the hole through which the light enters, the dimmer the image will be. Conversely, the bigger the hole, thr brighter it will be.
That's common sense, right? More light will obviously produce a brighter picture. But a larger hole also has the effect of making the picture more blurry. Meanwhile a smaller hole makes the picture sharper.
This brightness v sharpness 'trade-off' is a perennial feature of photography, and worth bearing in mind as you work through this series. With a lens we can always choose a focal point that will be sharp. But the sharpness of the area either side of the focal point, known as the 'depth of field', does depend on the size of the hole.
Why lenses are important
Lenses are, clearly, a very important part of photography. Although we've seen how it's possible to capture light and make a picture with a camera that doesn't use a lens (a pinhole camera), lenses enable us to do lots of things: determine the focal point, the magnification, how much of the world the camera sees (the angle of view) and the perspective.
Lenses work by gathering light and focusing it to an image.