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Digital Photo 9
> Rekha Gartonâ€™s beautiful self-portrait uses rows of corn as a natural frame to focus attention on the subject. 22 Digital Photo
take full control of sharpness in your shots by mastering depth-of-field. we show you how... WOrdS & PIcTUreS dan mOld
ontrolling aperture is one of the key skills to learn if you want to take full creative control of your pictures, so shooting in Aperture priority mode is something all photographers need to master. And although making the switch from Auto mode to Aperture priority may sound daunting, once mastered, you’ll be properly controlling the depth-of-ﬁeld in your pics and deciding exactly how sharp your images are from the foreground to the background.
In Aperture priority you set the size of the aperture in your camera’s lens while the camera sets an appropriate shutter speed to produce a balanced exposure. The aperture in a lens is no diferent to the iris of a human eye, they both open and close, to control the amount of light coming in, but what’s of real importance to creative photographers is how it afects the depth-of-ﬁeld in a pic. Last month we covered shooting with a wide aperture, and showed how on settings like f/2.8, the light
get front-to-back sharpness by creating a large depth-of-field Step 1 get sharper shots with a narrow aperture
ﬂoods in, providing a fast shutter speed and a shallow depth-of-ﬁeld, where only a little of the scene is kept in sharp focus. This is great for portraits, but there are times when you’ll want more sharpness throughout the frame, such as with landscapes. To hang on to as much detail as possible, you’ll need to create a big depth-ofﬁeld and that’s done by closing the aperture down to a setting like f/22. The only downside to this is that by selecting a narrow aperture, the light hitting the sensor is reduced, so you’ll need to shoot with longer shutter speeds. This can introduce camera shake into your pics if you’re shooting handheld, so if you’re using small apertures, make sure you’re shooting from a tripod.
minimum apertures explained The aperture is located within the lens barrel, so the minimum setting will vary from one lens to another. Lenses have their largest aperture speciﬁed in their name as a low f/ number (50mm f/1.8 for example), but to maximise the depth-of-ﬁeld we’re interested in the smallest setting and this will have a high f/number such as f/22. This isn’t written in the name, but if you’re buying a lens, and want to achieve ultra-sharp landscapes, it’s a key consideration. Zoom lenses tend to vary the minimum aperture depending on the focal length. At 18mm on an 18-55mm kit lens, you’ll be able to close down to f/22, but f/32 becomes available at 55mm.
Turn your D-SLR’s Mode dial to Aperture priority (A or Av); and you’ll be able to set an Aperture of your choice. For front-to-back sharpness you’ll need a small aperture, such as f/16 or f/22, and the camera will then work out the shutter speed for you. Remember though, due to less light entering the camera, this could be quite slow, so you’ll need a tripod or a high ISO setting to compensate for slower speeds.
> Shooting wide open lets the light ﬂood in for fast shutter speeds, and ofers a shallow depth-of-ﬁeld.
Step 3 shoot & review sharpness on the screen Step 2 pick an af point & focus in the right place At small apertures, your focus is less critical as you have a larger zone of sharp focus. However, focusing in the right place is still important in ensuring as much of the image is as sharp as possible. Change to autofocus and select an AF point which is about one third of the way into the scene. You can also manually focus a third of the way in, if you prefer to do it this way.
With the focus set and a narrow aperture dialled in, you should be safely recording most of the scene as sharp. Thankfully, however, in the digital age you also have a screen to check this on, so zoom in on the foreground and background to assess whether they’re critically sharp. If either is not as sharp as you want, set a smaller aperture (a higher f/number), or if you’ve reached the limit of your lens, and the foreground is blurred, focus a fraction closer than your current point. If your background is soft, shift the focus point further into the scene and try again.
> A small aperture requires a much longer shutter speed, but more of your scene will be sharply focused.
Digital Photo 41
inspiring images // INTERVIEW
AUSTIN THOMAS // inspiring images
~ t h e d i g i ta l p h o t o i n t e r v i e w ~
take a walk on the
wild side ANY CREATURE THAT MOVES IS A TARGET FOR THE LENS OF austin thomas. PHOTOGRAPHING A HOUSE SPARROW OR A HIPPO GIVES HIM EQUAL PLEASURE AS LONG AS HE CAN CAPTURE A MEMORABLE MOMENT WORdS BY LYNNE MAXWELL
52 digital Photo
WHITE HORSES When people ask Austin what he likes to photograph, he says “Anything that moves”, whether it’s dogs racing round a track or genuine wildlife. This photo shows the wild horses of the Camargue. “I wouldn’t classify them as wild, as in fact they’re in very large ﬁelds, with fences, in the Camargue region of France. To add impact to my pictures I always try to get down low, even it that involves getting wet...” digital Photo 53