66

slr camera skills

Digital Camera June 2014

stabilisation technology have been a game-changer as far as handheld photography is concerned.

What is image stabilisation? There are actually two types of

stabilisation. Canon, Nikon, Sigma and Tamron favour lens-based stabilisation, while Panasonic, Sony, Olympus and Pentax use sensor-shift stabilisation instead. They both do the same thing, though: detect camera shake and counteract its effects by moving either a floating optical element (in the lens) or the sensor (in the camera). The key advantage of sensor-based stabilisation is that it works for any lens attached to the camera, even an old manual-focus one. Lenses that have stabilisation built in, such as Canon’s IS (Image Stabilizer) lenses and Nikon’s VR (Vibration Reduction) ones, are more expensive, but the performance of each stabilisation unit can be optimised for each type of lens.

How will i know that image stabilisation is working?

Most stabilised lenses have an on/off switch on the lens barrel. With IS on, the system whirrs into life once you touch the shutter release. And we do mean whirrs. Optical image stabilisation can be noisy when it’s active, so much so that it can be picked up by the camera’s internal microphone when shooting video. You’re also likely to see the image

You don’t need to mollycoddle your lenses, but you do need to keep them clean. Here’s how to remove dust, dirt and fingerprints…

start with an air blowerThe first stage in cleaning a lens is to remove dust before you touch the front element with a cloth. if you do this with a can of compressed air, follow the manufacturers instructions with care. We prefer to use a manual air blower, as this can also be used to clean delicate areas of the camera too.

brush, then wipeUse a lens brush to remove any particles that the blower misses, then a microfibre cloth to buff away any oily marks. For stubborn residues, use a dedicated optic cleaning fluid and a disposable lint-free, non-abrasive lens wipe. Finally, fit a UV filter or other protective filter to protect the front element.

Clean the contactsdon’t touch the rear element of the lens – a gentle blast from an air blower should be enough to remove the odd bit of dust (hold the lens with the rear element facing downwards). don’t forget to clean the electrical contacts on both the lens and camera with a lint-free lens tissue too.

TECHNiQUE LookiNg AFTER YoUR LENSES

HoW To gET SHARp RESULTSimage stabilisation can help you get sharper handheld shots, but it’s not always the answer to soft images…

Lenses tend to be at their sharpest at mid-range apertures, such as f/8 and f/11. As the aperture gets

smaller, the shutter speed gets longer, so you may need to increase the iSo to get a shutter speed fast enough to reduce the effects of camera shake. This is usually 1/focal length of the lens or higher, such as 1/50 sec for a 50mm lens on a full-frame camera. image stabilisation enables you to take sharp handheld pictures at slower shutter speeds without increasing the iSo or using a larger aperture. Some stabilised lenses even enable you to get sharp results at a shutter speed that’s several times slower than you’d normally use. However, if you don’t use good lens technique, you’ll still end up with a picture with soft details and smudged edges.

HANDHELD

is

TRipOD

in the viewfinder or the Live View screen judder then become very still.

so why would i ever want to switch off a lens’s image stabilisation?

Image stabilisation draws its power from the camera battery, so you may be forced to switch IS off if you’re low on juice. If you’re working from a tripod, it’s best to switch off IS altogether, so that it doesn’t attempt to detect vibrations that aren’t actually there, which can lead to rather soft pictures. If you’re moving the camera to keep an active subject in the frame, you may need to switch off the IS system again. If you don’t do this, you’ll probably find the system will work against you, attempting to correct for the camera movement that you’re intentionally making.

Some stabilised telephoto lenses have an IS mode switch that lets you toggle between the normal IS setting (Mode 1) and a special ‘panning’ setting (Mode 2) where the camera only corrects movement in one plane – horizontal or vertical.Some stabilisation systems can even automatically detect when you’re intentionally panning or shooting from a tripod and will make any adjustments as necessary.

IS options differ between lenses, so there’s no getting away from it: you’ll have to refer to the individual lens’s manual to check how it will react in different situations.

A tripod will give you the sharpest shots possible at slower shutter speeds, but be sure to switch off iS!