Know your stuff

Se­lect the cor­rect auto fo­cus (AF) area to cap­ture pin-sharp im­ages when shoot­ing ac­tion sports

Getaway (South Africa) - - PHOTOGRAPHY MASTERCLASS -

Try­ing to keep a mov­ing tar­get un­der a sin­gle AF point – when it’s hard enough just to keep it in frame – is al­most im­pos­si­ble and pretty im­prac­ti­cal. Luck­ily our cam­eras have dif­fer­ent AF points and these can be com­bined in dif­fer­ent ways to suit ev­ery sit­u­a­tion. From a sin­gle AF point through to full auto, the maps dif­fer greatly. How to do it Go into your menu (or press your AF se­lec­tor but­ton) and find the AF Area se­lec­tion panel to se­lect and change your AF area. The maps will com­bine five, nine or all AF points (Auto) and a cou­ple of vari­ants in be­tween, de­pend­ing on your model of cam­era.

For best re­sults with mov­ing sub­jects, use one of the larger AF area set­tings, like Zone AF. These will give you a bit of lee­way for fram­ing your image. You can move these around the viewfinder, and they cover a big enough area to keep your mov­ing sub­ject cov­ered when track­ing. If you find your AF con­stantly jump­ing be­tween back­ground and fore­ground, try a smaller AF area while keep­ing the ac­ti­vated AF points over the sub­ject.

Full auto works when the sub­ject has a clean back­ground, like the sky or one that’s very out of fo­cus. But it will strug­gle to fo­cus on a sin­gle sub­ject when shoot­ing against a back­ground with de­tails that it can latch onto.

THE HUM­BLE SHUT­TER – WHAT DOES IT DO?

That iconic ‘click-clack’ you hear as you press the shut­ter but­ton is not ac­tu­ally the shut­ter but the sound of the mir­ror go­ing up and down. Iron­i­cally, even though it’s called shut­ter noise, the shut­ter barely makes a sound ex­cept for a very faint click­ing. At fast shut­ter speeds and large aper­tures, the shut­ter tends to cre­ate a bit of vi­gnetting (dark­en­ing of the cor­ners of the image), but not al­ways.

There are three main types of shut­ters and all of them do ex­actly the same thing, but in very dif­fer­ent ways: ex­pose the sen­sor/film plane to light for an ex­act amount of time, hence shut­ter speed. Leaf shut­ters Found in com­pacts and medium-for­mat cam­eras. These are built into the lens and are shaped like an iris that opens and snaps shut.

Fo­cal-plane shut­ters Found mostly in SLR and DSLR cam­eras. The shut­ter con­sists of two cur­tains that move across the sen­sor. The first cur­tain opens the sen­sor to light and the sec­ond blocks off the light. The faster the shut­ter speed, the smaller the gap be­tween the first and sec­ond cur­tain. When us­ing flash, this can be­come vis­i­ble if you shoot at a fast shut­ter speed (over 1/160 sec).

Dig­i­tal shut­ters Mostly used on mir­ror­less cam­eras.

These don’t have any mov­ing parts. This has its lim­i­ta­tions be­cause the CMOS (card reader) can’t read the in­for­ma­tion all at once but one row at a time. This has the ef­fect of re­duc­ing shut­ter speed

– an is­sue for pho­tog­ra­phers work­ing in 1/100 and 1/1 000 secs.

AUTO-FO­CUS TRACK­ING

ZONE AUTO FO­CUS

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