(While setting up this site in September 2020 I went looking for articles to add to it from my scattered archives. This is one that I came across that has less relevance in these days of ubiquitous digital cameras and powerful computational photography but is perhaps an interesting bit of history.)


Taking a decent picture requires two basic things: you must compose it properly and you must get the correct amount of light to fall on the film (or sensor, if you are using a digital camera). Both of these are something of an arcane art but there are some basic rules of thumb, described here, that will help to get things right. Overall though the most important rule is that there are no rules - this is art. Try everything and you might discover something you really like. Nonetheless familiarity with the ideas described here will help you guess better what the results of your experiments might be. To help you with all the things suggested here, you might like to take notes for each photo you take. Record the camera settings and any thoughts about why you want to take the picture. When you look at the results these notes might help you to get a better understanding of why a photo has been a failure or a success.


Beauty is in the eye of the beholder, they say. Actually, it is in the mind of the beholder. Most of what you see you actually invent because you can’t really see it at all. You can do a simple experiment to demonstrate this. Most people when sat in their living room feel that they can see most of it in detail most of the time. Actually, all you can really see is a very small area of detail and a lot of blur that prompts you to reconstruct the rest from memory. If you have something with large writing on it, e.g. a poster or a book cover, sit across the room from it and look at something about two feet to one side. You might think you can still read the writing but actually you can’t; you’re just remembering it. If you concentrate on keeping your eye pointed at the spot two feet to one side and try to read the writing out of the corner of your eye, you’ll probably find it is so blurred you can’t really even tell it is writing.

This explains why many pictures unexpectedly look so bad. You look at something and think it looks good but actually your brain is editing what you see in the context you are seeing it in and making sure you are only conscious of the good bits. A camera can’t do this and when you see the photo out of context you get to see what was really there. This means the photographer must do the editing consciously when taking the photograph. The main trick is to learn how to distinguish what you can really see from what your brain is trying to let you see. This is best done when looking through the viewfinder; try to think of what the view through the finder would be like as a photograph. Move your eye around without moving the camera to help you do this. Needless to say there is a knack to this and finding it is an important part of the art of photography. You might find it helpful to compare photographs of things with the things themselves and ask yourself why the photograph doesn’t look as good as you thought it would when you took it.

There are also some more basic rules which are easier to apply:

The rule of thirds

If you imagine a photograph to be split into thirds horizontally and vertically, as though a noughts and crosses (or tic-tac-toe) board was drawn on it, these lines are important. A landscape will tend to look better if the horizon is one third down from the top or one third up from the bottom. If there is a prominent tree or person, it might improve things if they are one third from the left or right. This isn’t a hard and fast rule (none of these are) but it is often worth considering.

The unexpected

Shocking people grabs their attention. Don’t always do the obvious.

The expected

Normality is appealing. People like pictures of things they can recognise. (I know this conflicts with the previous rule. That’s why this is art, not science.)


A camera, like a human eye, can’t always focus on everything at once. When composing a photo you need to make sure the right things are in focus. This can help a lot if you are photographing something on a cluttered background it might be lost in. If the subject is in focus and the background isn’t then the subject won’t get so lost. You can use focus in many ways to emphasise different parts of your composition. For more information on focussing see the notes on aperture setting, later.

Shadows and highlights

When you look around a scene, your pupil dilates to get more light from the dark bits and contracts to stop the bright bits from dazzling you. Your brain works further on what you see to help with this. None of this happens when a camera takes a photo; the same camera settings must work for the whole scene. This means you can end up with a photo where the well-lit bits look fine but the shadows are so dark you can’t see anything, or one where the shadows are fine and the well-lit bits just get washed out. To fix this you need to choose your composition carefully and choose your camera settings carefully (see later for more notes on this). If you are using a light meter, choose carefully what you take the reading from. You might consider using artificial light or a reflector to fill the shadows. When composing your photograph, try to remember how much your eye compensates for these problems (a lot).

Shadows and form

A photo is two-dimensional and has no depth. Much of the form in a photo is therefore built from the clues given by shadows. The shadows define and form shapes and hint at depth. The reason you can see shadows is because there is light falling on the scene from an angle (or angles) different from the one you are looking (or photographing) from. If the light were coming from your eyes, there would be no visible shadows because they would always be obscured by the objects casting them. This may sound irrelevant but actually it is a common problem in photography. If you have a flash gun mounted on the camera it is so close to the lens that you generally get very few shadows and photos can thus end up looking very flat and formless. You can get round this by using a flash on a long wire or by bouncing the flash off a reflector or by using very little flash so you get a combination of flash and other light. Different methods need different equipment and produce different results.

Another important feature of shadows is that most scenes are lit from many different angles so you get many different shadows combined. These all provide more clues to form and depth. Even in a normal room, most people have a big light shade. The effect of this is to make the light seem to come from many different directions (all the different points on the shade) and so cast a better variety of shadows. Most flash guns are pretty small and so cast light from one direction only. This results in very harsh, single shadows and can make a photo look terribly hard. If you don’t want this you need to soften the flash, usually by bouncing it off something larger.

Light Level

There are three basic factors controlling light level in a photograph: film speed, aperture and shutter speed. Each of these three also controls another factor in the photograph and so you need to balance these three depending on how you want the other factors set.

Film speed

Films come in a range of ‘speeds’ and a faster film needs less light to get the same results. Thus you might use a fast film for indoor or dull weather shots and a slow one for bright sun or with a lot of artificial light (e.g. a still life in a studio). However a faster film is more expensive and the crystals in the light sensitive coating are larger, causing the photos to be ‘grainier’. Film speed is the easiest choice to make. It is usually fixed by the time you come to choose your aperture and shutter speed so you only need to balance those two things against one another. Note that the film speed is also hardest to change because you have to change the film. This means that you need to pick your film carefully. If you are going to be using fast shutter speeds (e.g. for sports) or small apertures (e.g. for landscapes) then you may need to pick a fast film; if you are planning slow shutter speeds (e.g. for special effects) or wide apertures (e.g. for portraits) then you may need a slower film. Of course if you are using a digital camera then you don’t have to make this decision.


This is literally the size of the opening or aperture in the lens of the camera. Obviously, the larger it is the more light you get. The scale of measurement is the ‘f stop’ and a smaller number is a larger opening. This scale is set so that f1 gives you the same amount of light as if the lens wasn’t there at all. Most lenses can’t get this low because the glass stops some of the light getting through but you can have a lens with a very big front element which captures more light than you would get if the lens wasn’t there, e.g. f0.8. A very small aperture, letting through very little light at all, might be f22 - most lenses don’t have smaller apertures than this available.

The aperture also controls the ‘depth of field’. This is how much of the photo is in focus. When you set the focus on a lens, you are setting the centre of the focus and some things nearer and further away will also be in focus. For example, if you set the focus at ten meters you might find that things half as close (5m) are also in focus and also things twice as far away (up to 20m) - this would be a depth of field of 15m (from 5m to 20m) altogether. If you use a smaller aperture, you get a bigger depth of field as the lens starts to work like a pinhole camera. At f22, almost everything will be in focus. If you use a larger aperture, you get less depth of field so you can more easily pick things out from their backgrounds and foregrounds. Better SLR cameras have a ‘stop down preview’ button that lets you set the aperture that will be used for your photo as you look through the view finder so you can see what the depth of field will be. If you don’t have a stop-down button (or if pressing just makes the view finder go so dark you can’t see anything) you will have to try and guess the depth of field; experience helps a lot with this but remember that it is different with every lens.

Shutter speed

The shutter speed sets how long the shutter is open for. Obviously, the longer the shutter is open, the more light comes through. Shutter speeds might run up to 1/1000 (one one-thousandth) of a second, letting very little light through, and down to half a second or so. Many cameras also have a setting where the shutter stays open for as long as you keep your finger on the button, often called ‘bulb’.

Shutter speed also sets the ‘motion freezing’ aspects of the photo. If anything in a photo moves while the shutter is open it will be blurred on the film. This is generally not a problem but if you need to use a long exposure (i.e. a slow shutter speed), or are photographing a fast moving object, it can be important. It may also be desirable: try taking a photo of a waterfall or similar with a long exposure and all the water will be blurred giving an effect which can be very attractive (though something of a cliché). Or try traffic at night - you get long streaks where the lights are. If you are photographing a moving vehicle and track it with the camera, a long exposure (and accurate tracking) can give a sharp vehicle with a blurred background, resulting in a motion effect.

Don’t forget that it’s not just the subject that might move - the camera might too. If it does, and your shutter speed is too slow, you will get camera shake visible on the photo. The longer the lens you are using, the bigger the problem. To demonstrate this try looking through binoculars - the slightest movement of your hand and the image jumps about all over the place. If you are taking a photo with a camera and using a long lens or a long exposure, you may need a tripod or have to rest the camera on something to prevent it from shaking. As a general rule of thumb, the length of the lens suggests the slowest sensible speed for a hand held photo. If you are using a 50mm lens, don’t go below 1/50th of a second. If you are using a 200mm lens, don’t go below a 200th.


Picture taking is an art and the best way to learn it is to take a lot of pictures and keep notes so you know what you did and why, and thus can make judgements about what worked and what didn’t. When taking pictures, consider composition and light levels. In particular, consider some of these things:

  • Vision is very subjective. When composing photos, imagine the photo rather than the scene.
  • Split pictures into thirds in both directions.
  • Do the unexpected.
  • Do the expected.
  • Use focus to pick out (or conceal) the right parts.
  • Make sure the shadows aren’t too dark or the highlights too bright.
  • Use lighting angles to emphasise forms and depth.
  • Pick a suitable film speed to allow a good choice of aperture and shutter speed.
  • Use an aperture that gives the right depth of field and lets you use an appropriate shutter speed.
  • Choose a shutter speed to freeze or blur motion and that lets you use an appropriate aperture.

Above all, enjoy yourself.

Merlyn Kline