Here's an easy introduction to photography in just 2 steps...
1. Hold your camera at the right position and angle
2. Press the release button.
Am I kidding? Not quite...
Photography is not about buying the perfect equipment, using the perfect film, finding the perfect location, getting the perfect exposure and sharpness. You can waste lots of time perfecting this most well-defined part of photography, and still make bland pictures.
Photography is all about composition: look what you're shooting! The first photos I made were sharp and well exposed, but were often disappointing because there was something in the picture not quite right: there were distracting elements, or the subject was too small or accidentally cropped off. I found that, often, a small detail can make or ruin your picture. I really had to learn to look what I was doing, what is really there in the viewfinder, rather than what you might think there is. The world you see through the viewfinder is not quite like the world as a naive person appreciates it.
One's perception and appreciation changes as one goes along. Some things you find wonderful now you might find unremarkable in the future, and vice versa. Other things in one's perception never seem to change, and some pictures only seem to gather more appreciation as time passes. Such change in perception might be caused by various things. One of them is that of technical ability: when one finds out that a particular kind of picture is very hard or very easy to take, one's appreciation of such pictures changes. Some people seem to get really involved in finding rare circumstances to make difficult pictures. It's as if their pictures are trying to say: `look at how hard I am to make!'. I suppose there's some rarity value or technical showing-off value in many pictures, but basically, I don't really like this part of photography. I just like nice pictures, and if they're easy to take, well, that's a nice bonus. I like wonderful compositions made in one's own back garden.
There is another point about the difficulty factor I wish to make. Difficulty can be faked, for example by means of digital manipulation. Generally, a lot of pictures are manipulated, ranging from blurred or darkened areas to shifted hues to montaged skies to combinations of multiple pictures. Several of the most popular pictures at naturephotogallery (see below) were elaborate montages of multiple pictures (even though they were technically not all that well done, which says something about how closely people look at pictures!), in fact it seems I was the first to note this in several cases. The montaging served to make the pictures depict rarely occurring situations, which strongly contributed to their rating by other people. When people found out they were not real photos, they were often angry. If these pictures did not have such a lot of this `difficulty' value, people would not be so angry. In fact, when looking at them from a purely asthetic viewpoint, most om them werent' all that special.
There's lots of basic information about composition in various books and tutorials, such as rules of thumb. You'll also find lots of pictures, and when examining them, you will find many cliches. I'll skim through some of the best-known rules and cliches shortly. An issue with both is that they change one's perception also.
Firstly, one might become influenced by them, fixating on them as if they are rules of nature. For example, I made a picture of bell flowers with a nice wild pink background that was supposed to convey the rich growth of the garden, and the first remark I got was that the picture contains so many distracting elements. So, maybe this spectator really found these elements distracting, even when ignoring rules of thumb and cliches. But what's at fault then is not my breaking of the rule `eliminate distracting background elements', but my failure to convey the richness of the garden through the background colours.
Secondly, once one realises how many of these rules are practiced, one can't help but start looking at pictures while reading the mind of the photographer: `oh, here he clearly adhered to rule #834, and here, he was trying to achieve effect #287'.
Thirdly, knowing this, the photographer might also start playing with the rules: a boring rule might be used very creatively, or a very obvious rule may be broken very deliberately to create some effect.
I'll continue with some basic principles. Some are from others, some are well-known rules, some are my own.
Seek out subjects purposefully. Find some nice places in your neighbourhood, and don't be sorry that you don't have your favourite such-and-such nearby. Rather, work with what you have. For example, it wouldn't be wise of me to specialise in mountain photography in the Netherlands, and rather, I'd go for woods, heath, dunes, meadows. Usually, I find that I know very well what I like when I see it. When I walk through a scene, it's often the same things that keep attracting my attention. I learned that it is worthwile to take more time with the most remarkable, striking subjects, and less with the rest.
Find a visual composition that works well. This is the most difficult part, and is worth some further examination. A few standard rules:
Remove distracting elements. Make sure there isn't some very disturbing element left in the corner, such as a corner of road or a strip of horizon on a flower shot, or a piece of rubbish or a fence in a landscape shot, or an unfocused blade of grass or leaf in front of your lens. While this sounds very obvious and boring, even very small things can be disturbing, and I find various of my pictures still contain such disturbing elements, some of them even too small to see properly in my viewfinder. Cropping the picture afterwards helps, and it's an interesting exercise to play around with cropping your photos to see what difference it makes. At first, I just used slides which can not easy be cropped afterwards, and all the cropping had to be done in the viewfinder, but after I got a digital camera, cropping was made easy, and I learned a lot from playing around with image manipulation software.
Make your subject stand out. Make sure your main subject is clear and the viewer's eye is drawn to it. In pictures, contrast with a background is usually worse than one expects. One of the things that causes this is the fact that 3-D parallax cues (those obtained by processing the differences of the slightly different pictures of your two eyes) are missing. This means the photo doesn't have the parallax depth cues that you get when seeing it, and also, that the background isn't filtered out from consciousness because its parallax is widely off as compared with the foreground (one might call this effect `parallax blur'). It sometimes requires examining various angles to find the proper contrast. In macro shots, you can blur the background by using a limited depth of field. Some people use cloth that they drape behind the subject to get a good contrast or colour scheme.
Get the overall visual pattern right. One good practice is to look at your picture in an abstract way: as a collection of lines, textures, and shapes. A well-known rule is: if the subject should not fill the view, do not place it in the dead center, but rather, at a third from the left or right (the rule of thirds). And: if there is a straight line such as a horizon, do not place it in the center of the picture, but rather, have 2/3 sky or 2/3 ground. While the psychological background of this rule remains somewhat of a mystery to me, it seems to work in many cases. A rule that is less well known is that having the horizon in the center does work when the picture is in portrait orientation.
There are also rules connected to the meaning of the subjects. For example, a well known rule is that when a person/animal is looking or going into a certain direction, make sure that there is some room in that direction so that s/he/it is not looking/going `out of' the picture.
Here are some links that explain basic compositional rules.