16

Technique MYTHS BUSTED

Biggest

photography

myths

busted

From focusing myths to kit lens prejudice,

A nd y We s t l a ke challenges various cliches

1

Focus one-third of the distance into the scene

This piece of advice pops up all the time, but it’s an over-simplifi cation. It

assumes the depth of fi eld (DoF) extends twice as far behind the focus point

as it does in front, but this is only true in a narrow set of circumstances: for

instance with a 50mm lens on a full-frame camera at f/8, with a subject three

metres away. Change the lens, aperture, focus distance or even sensor size

and the front-to-back DoF ratio also changes, often substantially. With

close-ups, depth of fi eld is almost equal in front of and behind the focus

point, whereas with distant landscapes, it extends almost entirely behind.

5

Yourlenses’sweet spot is f/

Oneholdoverfromthe days of shooting 35mm

filmis theideathatyou’llget the sharpest images at

f/8.Butthisisn’ttruewith smaller formats, owing to

diffractionblurringbecoming signifi cant at larger

apertures.Asa result,you can often expect the

sharpestoverallresultsat f/5.6 on APS-C and f/4 on

MicroFourThirds.Witha 1-inch sensor compact, in

principleyoushouldgetthe sharpest pictures around

f/2.8,buttheirsmallandoften ambitious zooms

normallyneedstoppingdown further to sharpen up the

corners.If you’reworried, check each lens’s sharpness

acrossitsaperturerangewith the camera on a tripod.

3

Medium format gives the

shallowest depth of fi eld

The laws of optics mean that for any given angle of

view and aperture setting, larger formats give shallower

depth of fi eld. So you might come across photographers

waxing lyrical about the lovely blurred backgrounds that

only medium format can provide. But the fl aw with this

argument is that much faster lenses are available for

full-frame cameras, with only a handful of medium-

format optics sporting apertures larger than f/2.8. So

if ultra-thin DoF is your thing, then using full frame with

f/1.4 or faster primes is the best approach.

4

Set your camera to Adobe RGB

Most cameras have the option to choose between

sRGB and Adobe RGB colour spaces, and the latter

can describe a wider range of colours. What sensible

photographer wouldn’t want to do that? In practice, though

it’s not that simple, because cameras usually output the

same colours regardless of the colour space selected.

But there’s a risk Adobe RGB fi les might display or print

incorrectly, so sticking with sRGB JPEGs is safer. If you’re

onlyshootingraw,thissetting is irrelevant anyway.

2

EverythingwithinDoFshouldlooksharpat100%
DoFcalculationsassumea specific ‘circleof confusion’todefinewhatshould
lookacceptablysharpin print.Conventionallythey’renotverystringentat all;for
example with a typical 24MP sensor, the circle of confusion would be 5 pixels in
diameter. If you want a fi nely detailed large print, you’ll probably need to use a
smaller aperture than that indicated by a lens’s DoF scale.

If you want shallow depth

of field, full frame is

the best format to use

Nikon D800E, Zeiss Milvus 1.4/85,

1/640sec at f/2, ISO 100

Use larger apertures

with smaller formats to

avoid diffraction blur

Fujifilm X100T, 23mm f/2,

1/80sec at f/5.6, ISO 1250

With distant shots, it’s

best to focus towards

the front of the scene

Olympus E-M1 II, 12-100mm f/4,

1/400sec at f/5.6, ISO 200