In the last instalment I talked about bracketing, a key technique for the creative photographer. Soon I want to get on to some of the more exciting areas to do with composition, etc. But there are still some technical areas to talk through.

Peewiglet asked a good question. She could see that bracketing was important but how should you bracket. Should you change exposure or change shutter speeds? A good question. Both will do the job but both have very different, and important, effects on the photograph.

So, here goes. Those of you with low attention spans can go to the top tips section at the end.

To recap. I want to increase exposure by one stop. M camera is set at f16 aperture and 250th of a second shutter speed. I have two choices. Firstly, I could open up the aperture to f8. Secondly, I could reduce the shutter speed to 125. Both of these options will effectively double the amount of light that hits the camera’s sensor.

In Landscape, Aperture is King

For this series I am assuming that most of us are most concerned with landscape photos (although we won’t forget others). Generally a landscape photographer will want to stick to a higher aperture and will let in the light by slowing shutter speeds. This is why a tripod can be so important when photographing landscapes in poor light. In poor light I might want to shoot at F16 but may have to use a shutter speed of less than 1/15. Camera shake becomes an issue below 1/30th second. But why concentrate on aperture?

Depth of Field

Depth of field is the key. The smaller the aperture of your camera (the higher the number) the greater the depth of field of your shot will be. But what is depth of field?

Imagine we’re taking a photograph of two hikers. The hikers are in middle distance. In other words we can see them clearly, but there is still enough landscape in the photograph to keep things interesting. Obviously we want the hikers to be properly in focus. But we want the surrounding landscape to be in focus as well.

When your camera focuses on the hikers it will maintain the sharpness of focus for some distance in front of the hikers as well as behind them. Changing the aperture alters the amount of overall distance which stays in sharp focus. Reduce aperture (increase the number) and the depth of field increases. Open up the aperture (lower the number) and depth of field reduces.

Lowering Depth of Field

For some techniques you may actually want a tiny depth of field. We’ve all seen portraits taken as close ups where the background of the portrait is blurred. The blurring means that our whole focus is on the face that is being photographed. The subject might be in a garden. Behind the subject might be a series of brightly coloured plants. In the final photo the background might appear a lovely blur of colour.

This is obviously not the effect we want — most of the time — when shooting landscape.

Sometimes landscape can be flat, in other words, much of the detail of the shot will be in the distance. In this case depth of field may not be that important. But often great landscapes mix the wide detail of a scene with something in the foreground, say, a rock or bridge to give depth (I’ll put some photo examples up shortly).

Obviously, when we have something in the foreground we want that in focus as well — together with the main part of the scene.

Go For Depth of Field

This is a simplistic account — read a good book to really understand this. But, in most landscape photography, we are looking for good depth of field. So, try and shoot around f11 to f8 (or higher)

Wide Angle Lenses

Lenses range from wide angle to telephoto – the telephoto being the zoomed-in end. One more thing about depth of field. Wide angle lenses — or wide angle settings on the zoom lens — will automatically have greater depth of field. The more that you zoom in (the longer the lens) the less depth of field there will be, which is why zooming in on landscapes produces pictures with no ‘depth’ to them.

Why Can’t I see This Depth of Field Thing When I look Through the Viewfinder?

When you look through the camera lens you’re not looking at the same image as the sensor – on an SLR you’re looking through a mirrored image, with the lens right open. The camera only sets aperture when the camera is fired. You don’t have to worry about this, but some cameras have a depth of field preview button. Press this and you can see the effect of depth of field, however, the image in the viewfinder will be much darker than usual (as you’re not looking at an image with the aperture full open).

Summary and Top Tips

Depth of field is difficult thing to get your head around. Again, practice makes perfect. And practice taking some head and shoulder portraits, opening up the aperture and blurring the background — you’ll get more of a feel for the subject.

But, in very general terms, when taking landscape shots:

1. Don’t shoot at the highest end of the zoom;

2. Try and keep the aperture to F8 and above (11,16,22) – use 5.6 as the very widest setting in poor light.

3. Bracket using shutter speed rather than aperture.

The Natural Sharpness of a Lens

Finally, there’s one more important thing about keeping the aperture at the smaller end of things. Camera lenses do not have the same ’sharpness’ across all ‘focal lengths’. The sharpest point on a lens tends to be around f11. When shooting landscapes try for the sharpest pictures possible — you won’t regret this, especially if you ever want to make big prints!

If you’ve still not got this, don’t worry. Give me an email and I’ll try and explain it in more detail! This is one of those areas where a good book (see introduction) is worth its weight in gold.