Flash modes and what they do

DRIVE MODES

FLASH AND FLASH MODES

Be it a high-speed action shot or something more sedate, your DSLR can shoot fast sequences of images that means you won’t miss any of the action. In addition, if it has a built-in ﬂash, then you will be able to use it to add even more illumination on a scene. Let us have a look at some of the key features of both these DSLR tools

Drive modes

Your DSLR will have a variety of drive modes – settings that make the camera shoot one image, a sequence of images or delay the

ﬁring of the shutter for a pre-set period of, say, 10 seconds. There are times when it is useful to know when to use them and why.

Flash and ﬂ ash settings

Many DSLRs have a built-in pop-up ﬂ ash unit. The pop-up ﬂ ash is great for ﬁ lling in shadows in daylight or closer shots in low light but they are also relatively low-powered units, so can only properly illuminate a subject up to about three metres away from the camera. They are not good for illuminating larger areas. For that you’ll need to buy an accessory ﬂ ashgun, which sits on the camera’s hotshoe.

The built-in ﬂ ash can be good for a ﬁ ll-in in daylight but can sometimes provide very harsh light if the subject is quite close. In addition, if you have your lens hood ﬁ tted, it can obstruct the ﬂ ash light and create unattractive shadows across your shots. And, because the ﬂ ash unit is close to the lens, it can make the camera susceptible to redeye (see Redeye Reduction Flash to the right).

AUTO-FLASH MODE

REDEYE REDUCTION MODE

SLOW-SYNC MODE

AUTO FLASH

The basic point-and-shoot ﬂ ash setting that ﬁ res when the camera ‘thinks’ it is needed. In many cases, the ﬂ ash pops up automatically (if using a built-in unit), saving you the worry of knowing when to use it. In some modes the camera may indicate ﬂ ash is required with a small ﬂ ash ‘lightning’ symbol in the viewﬁ nder.

FORCED FLASH (FILL-IN FLASH)

In this mode the ﬂ ash is set to ﬁ re all the time, whether it is required or not, even

in daylight. You can use it to ﬁ ll-in shadows (ﬁ ll-in ﬂ ash) or for when you need an extra puff of light to add sparkle to a shot, boost colours and, with portraits, add an attractive light to your subject’s eyes.

FIRST AND SECOND (OR REAR) CURTAIN SYNC Normally, the ﬂash ﬁres immediately after the ﬁrst curtain of the shutter is fully open. But when taking pictures using a slow shutter speed the subject can appear to be moving backwards, as it leaves a trail in front of the subject. With Second Curtain Flash Sync the ﬂash ﬁres shortly before the second curtain closes. The result is a more natural ambient light trail that follows the subject.

SLOW SYNC FLASH

With this technique you ﬁ re the ﬂ ash in conjunction with a slow shutter speed. It has two main uses: to create interesting motion blur images with moving subjects (so they’re part blurred, part sharp) and to show a subject in the context of a dimly lit environment (such as a dimly lit room or outside at night with a lit building behind). With normal ﬂ ash the background would disappear in a sea of blackness, but with

Single shot mode

As the name suggests, in this mode, when you press the shutter button to take a picture a single shot is taken and even if you keep your ﬁ nger on the shutter release, it will not do any more. To take another shot you must release the shutter button and start again. Use this mode for static subjects or portraits and the like, where you know the subject is not going to suddenly run off.

Continuous mode

It is all very well being able to shoot a static subject and get it focused, or include yourself in a shot using the Self-Timer setting. However, for subjects that are moving (or if you’re moving) at, say, a sports event, you will need to use your DSLR’s continuous shooting mode. When set, the shutter will keep ﬁring as long as you keep your ﬁnger pressed down on the shutter button.

Self-timer mode

DSLRs have a delayed shutter mode that enables you to get into the shot after the shutter has been pressed. Typically, you focus, press the shutter button and run into the scene while the camera beeps a count- down or ﬂ ashes a small lamp, or both. The amount of delay can (usually) be pre-set, typically for two to 20 seconds. The self-timer is also useful for long exposure tripod shots, to avoid vibration from touching the camera.

Depending on the camera, the frame rate (the number of images per second that can be captured) will vary, but is typically between three and ten frames per second (10fps). One limiting factor is the size of the buffer memory. Think of this a reservoir of images waiting to be processed and sent to the memory card. The larger the buffer (or smaller the ﬁ le size of the image) the more it can hold and the longer your camera will continue to shoot before the buffer ﬁ lls.

Intervalometer mode

This is a timer mechanism on some DSLRs (or a function on their wired remotes) that takes a series of images at predetermined time intervals, making them ideal for time lapse photography or remote shooting. This is different from a self-timer (which takes one shot after a predetermined time interval

–see Self-timer mode, left) as the camera will continue to shoot at the time interval selected until it is stopped or the memory card is full.

When the buffer memory is full, the camera will either slow down, going from, say, ﬁ ve frames per second to three, as it moves images across from the buffer to the card. Alternatively, it may just stop,

as the processing resources needed to move images to your card become too great to do both shooting and storing of shots at the same time. Once all the waiting images have successfully buffered across to the card, you can start shooting again.

FILL-IN FLASH

FLASH-OFF MODE

slow sync ﬂ ash you can illuminate a foreground subject while keeping the ambient light exposure correct.

REDEYE REDUCTION FLASH

Redeye Reduction Flash is a method of preventing or reducing the effect of redeye, a phenomenon caused by light reﬂ ecting from the retina out into the camera lens.

A large pupil size can aggravate the problem so it’s often evident in low light

ﬂash shots. To prevent or reduce it, the camera either ﬁ res a burst of ﬂ ash pulses or emits a beam of bright light. Both are designed to reduce the subject’s pupil size, but this mode rarely works well in practice.

FLASH OFF

Sometimes you’re in a situation where ﬂash isn’t allowed (eg museums) or your subject is too big or far away for the ﬂash to light it. In these instances turning it off will instead cause the camera to select a slow shutter speed to compensate – so you’ll need to ﬁnd a steady support for the camera.

REMOTE FLASH TRIGGERING

Some DSLRs offer ﬂ ash units (or acces- sory ﬂ ashguns) that can remotely trigger (using infrared, wi-ﬁ and/or the ﬂ ash light itself) multiple ﬂ ash units not connected to the camera. This is useful for lighting large areas (you place the other ﬂ ash units where needed to help with the illumination, eg. backlights to ﬁ ll shadow areas) or for creative effects not otherwise achievable with a camera-mounted ﬂ ash alone.