A beginner's guide to DSLR cameras

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So you've got a fancy new camera but haven't moved past the automatic settings? We've got some suggestions that will help you dip your toes in the water. Of course, there are many things to master, but here are five key lessons to test out on your DSLR before heading on your trip.

1. Aperture Priority: let the right light in

One of the challenges of travel photography is capturing the moment. While some sights are static (landscape, buildings, etc), most are fleeting. As a consequence, a lot of DSLR users keep their cameras on full automatic (Program mode) so they are free to concentrate on the composition of the scene. Unfortunately, Program mode is rarely up to the challenge. I suggest you use Aperture Priority mode instead.

This is an example of shallow depth of field when the aperture is large (that is, a low number: f/2.8). Having focused on the woman having hair removed from her eyebrow, the woman closest to the camera is out of focus, as is the man and bike behind. (Ho Chi Minh City, Vietnam)

In Aperture Priority you choose, unsurprisingly, the aperture - ie. how much light you want to let into the shot - and the camera adjusts the shutter speed for the right exposure. Just as your pupils dilate to absorb more light at night when it's harder to see or compensate for harsh sunlight by getting smaller, the aperture setting is an artificial way of doing this.

A typical lens has an aperture range of 2.8 to 22 (or, as it is more properly written, f/2.8 to f/22). The lower the number, the larger the hole letting in light. And the more light you let in, the shorter the depth of field. That is, if you set the aperture to f/2.8 then you can choose what distance from the camera is in focus (the best short 'depth of field' effects are found when the camera is close to the subject in focus); whereas, if you set the aperture to f/22 then (almost always) everything in the frame will be in focus (near or far). The less light you let in, the sharper the detail as well, which is why landscape photographers like Ansel Adams preferred apertures around f/64. Portraits of people, however, are best done with more light (eg aperture numbers around f/2.8) as this blurs the background, making the person 'pop out', so to speak.

These two photos are identical in composition, but the image on the left was taken with an aperture of f/2.8 (the lens' largest hole) and the one on the right at f/22 (the smallest hole). At this image size they look to have the same amount of detail, but if we zoom in on the buildings in the background, the photo taken at f/22 (right) is much sharper.

Choosing the right aperture for your subject is a fine art sometimes. With the food image below, I set the aperture at f/4. If I went lower (eg f/2.8) then not all the food would be in focus; if I went higher (eg f/5.6) then I wouldn't get the blur around the edges and consequently the edges of the frame would be a distraction from the 'focus' of the image. Using this effect is standard for head portraits of people because the background is naturally separated from the subject's face.

(Roti Canai, Kuala Lumpur, Malaysia)

Having said all that, choosing the right aperture for your subject becomes less of a luxury when you are in low light. During the day you can usually choose any aperture you like. But when you're inside - or it's early morning or at night - you'll need to lower the number of the aperture to let more light in. So once you've chosen the aperture you want for the subject then check the shutter speed that is displayed by the camera. You will need to lower the number (eg from f/22 to f/16) if the shutter speed is below 1/60th of a second (unless you are using a tripod) as your hand isn't steady enough to avoid blur at this speed. Or, alternatively, you can increase the ISO setting (see below). (Avoid using a flash as much as possible.)

The aperture is at f/2.8 (the lowest for the lens) so I increased the ISO to 6400 otherwise there would've been movement blur (Jamie Oehlers Quartet with Megan Washington, Melbourne, Australia)

2. ISO setting: get sensitive

There are two big benefits of digital sensors over film stock. First, they are far more sensitive to light. Second, the sensor's sensitivity is adjustable with every shot. (Basically, the higher the ISO, the faster the camera's sensor. So in dark conditions you can increase the ISO setting and get sharper, clearer images. See the image above of a jazz band.) With film, you inserted your roll of 36 with an ISO (or ASA) rating of 100 and you were stuck with that sensitivity till you finished the roll. That was fine if the light didn't change or you didn't go inside, but most of us want more flexibility.

Difficult one, with both dark and bright areas of equal importance. I opted for f/10 and 100 ISO, but I had to do a bit of processing to lighten the columns (Ibn Tulun, Cairo, Egypt)

Again, most DSLRs have automatic ISO, but I've never found it to be helpful. Switch it to manual ISO. If you're outside during the day, try to keep the ISO down as low as possible (no more than 300). You want to keep the ISO low because when you increase the ISO, the noise also increases. Most DSLRs now have ISO settings that exceed the 10,000s, but the quality of the images quickly drops off with every 1000 increase. Every sensor has a different signal-to-noise ratio, so before you go on your trip take numerous images of the same thing in low light, increasing the ISO incrementally with each shot. Then zoom in on the results to gauge where the noise becomes unacceptable to you. Knowing your camera's limits in low light will improve your signal-to-groan ratio later.

3. Aperture & focus lock: zero in on the subject

Here I locked the aperture/focus on the customers on the left. If I had metered the exposure on the sea at the centre of the image then the foreground (customers and chairs) would been under exposed (dark) (Gili Trawangan, Lombok, Indonesia)

I'm a big fan of auto-focus, but if the main subject of your image isn't in the centre of your composition, then it won't be focussed or correctly exposed as this is where the camera's light metering and focussing grid is typically situated (they can be moved, but this is slow and painful to do for each shot). To overcome this, aim the centre of the lens at your main subject and half press the shutter release. Once your subject is focused, lock this setting. (Most DSLRs have a button for this, but if yours doesn't then it may have a Function button that you can assign this task to. Canon DSLRs have a system called 'One Shot' that locks focus and exposure when the shutter is half pressed.) Now you are free to move your frame to the composition you want and take your picture - your smart DSLR will remember where you wanted to focus.

The  closest basket of fish is not in the centre of the frame so I first focussed on it then reframed the composition so that it is at the bottom of the image. The shallow depth of field is achieved with f/2.8 (Ho Chi Minh City, Vietnam)

4. Adjusting exposure: see things in the best light

The camera doesn't always get the exposure you want. In fact it rarely does. Sunlight and artificial light have varying subtleties, and each person will have their own exposure preferences. So DSLRs come with exposure compensation. Exposure compensation is a button on your camera (or - less accessible - in its Menu) where you reduce or increase the exposure of your next shots. If you don't get the best exposure then colours will be drained and details will be lost in bright or dark areas. You'll be surprised how much just a little tweaking of the camera's exposure will improve your images.

For example, the first photo of the train station above (left) is taken with factory exposure settings. I'd set the aperture to f/6.3 and the camera thought the optimal shutter speed would be 1/250th of second. For the second (on the right) I reduced the exposure compensation by -1.0, which changed the shutter speed to 1/500th of a second - halving the amount of light coming in. The first photo looks faded; the second has richer colours and contrast more appropriate to the actual early evening light.

5. Shoot in RAW: keep your processing options open

DSLRs can shoot in JPEG or TIFF which allows you to download the images to your computer and use them immediately. But when you shoot in RAW, which is the most basic data from the sensor, you are able to do more processing later. For example, if the image is under- or over-exposed then your processing program will be able enhance it more than if it was JPEG. Two of the best image processing programs for beginners are Lightroom by Adobe and Aperture by Apple.

I did everything possibly wrong when I took this photo on a drunken amble home in Rome. Luckily I was resting the camera on a barricade so there is minimal blur. The ISO is 100 and the aperture isn't the lowest, but I took it in RAW so I could recover the image somewhat (Basilica di Santa Maria Maggiore, Rome, Italy)

This is the same image without any processing

Mark Broadhead is Lonely Planet's librarian and social events chronicler. He runs the weekly Lonely Planet photography competition.