If you’re a regular reader of this column, you probably fall into one of two categories:
Category one contains the fun snappers, who love taking pictures and would like to learn a few quick tips to improve their shots. But as soon as they start reading about focal lengths and white balance they start to worry and put the camera back into auto mode.
If you belong in category two, you can be regarded as a hobbyist. You already know the basics and are constantly striving to add life and impact to your shots. And you’re not afraid of taking your camera out of its auto modes – you really enjoy getting your hands dirty searching through the menu to change the ISO settings, especially if it means you can turn off your flash.
But there’s good news for everyone. We’re going to show you some techniques to adjust a parameter called depth of field (DoF). You’ve probably seen photos where the chosen subject matter is in sharp focus, while everything else is blurred. That’s an example of a very narrow DoF, and it’s precisely the effect we’re looking for.
DoF is the photographer’s offside rule: everyone understands it but nobody can explain it succinctly. But here goes. DoF is the distance between the nearest and farthest objects that appear in acceptably sharp focus.
Extreme DoF is one of a photographer’s most powerful artistic tools. Some cameras struggle with DoF, so we’ve included tips that will work on even the most modest of models. And if your digicam really can’t step up to the plate, there’s always editing software to fall back on.
So give it a go. DoF is a great effect all photographers can benefit from, no matter which category they fall into.
How to adjust depth of field manually
1. If you’ve got an old or cheapish camera, the chances are you won’t be able to control it manually. This makes playing with DoF tricky – but not impossible. Even the most basic digicams have preset shooting modes (landscape, sport, portrait and so on), which can be found in the menu.
2. Mastering these modes will allow you some control over your camera. Different modes will alter the aperture and shutter-speed settings, making it possible to obtain some DoF effects in your shots. If you want everything to be in focus, for instance, shoot in landscape mode. This will select your camera’s smallest aperture.
3. If you’d prefer to take a shot with a shallow DoF, where the subject is in focus but the background and foreground are blurred, shoot in portrait mode. Unfortunately, you won’t be able to subtly fine-tune DoF – you need a more expensive camera’s manually controlled settings for this.
4. If you own a good digital camera, you can obtain slightly more control over DoF. The Macro mode, for instance, can produce some dramatic results. With your subject in sharp focus close to the lens, the background will be blurred. But this isn’t going to work with a subject that’s more than a foot from the lens.
5. To create shots with real DoF, you need a camera that allows you to shoot in aperture-priority mode. This is usually indicated by the letters A or A/S. This mode allows you to manually set your aperture size. The camera will automatically change the shutter speed to compensate for the amount of light you’re letting in.
6. You can now control DoF by increasing or decreasing your aperture. The bigger the aperture, the narrower DoF will be and the more blurring will occur. Remember that a lower f number indicates a larger aperture, so an aperture of f-2.8 is bigger than f-16. This is because the figures are the bottom half of fractions.
>> NEXT PAGE: HOW TO ADJUST DEPTH OF FIELD WITH EDITING SOFTWARE
How to adjust depth of field with editing software
1. Editing software can’t sharpen a blurred picture. So if you want to add DoF to a shot, it needs to be completely in focus. Follow steps 2 or 6 in the previous workshop or, if you’ve got a fancy camera, look for the flower on your mode buttons. Select this and scroll through to find the infinity mode.
2. Once you’ve taken a shot that you’re happy with, open it in the image-editing suite of your choice. In Adobe Photoshop Elements – which we’re using in this walkthrough – upload a batch of new photos into the organiser, highlight the image you want to work on and choose Edit, Go to Full Edit.
3. Your chosen image will now open up in a new editing window. If your subject is at the centre of your composition, you can use Elements’ excellent Radial Blur filter for a quick, simple DoF effect. This will blur the image outwards from the centre, leaving the subject in focus. Simply select Filter, Blur, Radial Blur.
4. A Radial Blur dialogue box will pop up. Choose Zoom as your Blur Method; under Quality, select Best. Now move the slider to adjust the amount of blur and hit ok. We’re using Elements 5.0, which doesn’t have a preview option, so we’ll need to try these steps a few times to get the image perfect.
5. The main subject of your photo may well be off-centre. In these circumstances you’ll need to get slightly more involved with your software to create a striking DoF effect. Select Rectangular Marquee Tool from the toolbar on the left and a new option bar will appear at the top of your window.
6. Change the marquee from rectangle to elliptical by selecting the circle on the new option bar. To soften the DoF effect, change the Feather value. We’ve set it to 20px, which is about right for a photograph shot at 8Mp – increase this value for more detailed images. Now draw a circle around the main subject.
7. The next step is to gradually blur the background radiating out from the circle you’ve just drawn. Eventually the only sharp element in the photo will be inside the marquee you’ve created. To work on the exterior of the circle, choose Select, Inverse or hit Shift, Ctrl, I. (That’s I for inverse.) Select Filter, Blur, Gaussian Blur.
8. Make sure the preview box is ticked. Adjust the slider to give your picture a nice subtle blur, checking the effect in the preview window. Now simply repeat the process, but increase the size of your marquee and the amount of blur each time. The more steps you do, the more subtle the DoF effect will be.