Pillars of photography

OrThe Exposure Triangle

The Power PlayersAperture

Size of the hole that lets light into the camera

Shutter SpeedHow long the light is allowed to enter the camera

ISOHow sensitive the media recording the image is to

light

ApertureThe “hole” story

ApertureThe aperture is the hole that allows light to

travel through the lens of the camera.

Likely one of the most quoted, and least understood photographic term.“What was your aperture setting?”

F 16 ”Looks really good”

Generally speaking, people ask about aperture settings, however they don’t ask about the ISO setting or shutter speed.

ApertureA normal issue people have when discussing

aperture is that a large number results in a small hole….how?The aperture value, often referred to as an F-Stop

comes from a mathematical equation. Focal Length of lens / Physical size of opening

100 mm lens/ 25mm opening= F4 100 mm Lens/ 10mm opening= F10

You will get a bigger number with a smaller hole and a smaller number with a bigger hole due to the math of division.

ApertureAnother thing that messes people up is how is

F5.6 to F6.3 twice the light?Again, this is a math thing….derived by focal

length of lens, physical size of the opening and the good old (pi)r2A larger aperture allows more light to enter the

camera in less time, this normally equates to a faster shutter speed. Conversely, a smaller aperture will normally make for a slower shutter speed.

One of the biggest things you need to know about aperture to get started in photography is this:It controls depth of field

Depth of fieldHow much of your image do you want in focus?

Just the persons face, I want the background blurrySmall F-Number, (i.e.: F5.6), this will keep the subject

sharp while blurring the background.Everything…I want it all

F16 to F22 are good numbers for keeping the entire image in focus.

For example…

Shallow DOFSettings for this shot were:

ISO: 100

Aperture: F6.3

Shutter Speed: 1/320th of a sec

Focal Length: 163mm

Deep DOFSettings for this shot were:

ISO: 100

Aperture: F22

Shutter Speed: 1/13th of a sec

Focal Length: 28mm

What is Depth of Field?Depth of Field is a term put to the amount of

image that is in acceptable focus.There is lots of tecnobabble on this subject,

however suffice to say that the following rule of thumb applies to your focal point:Two thirds behindOne third in front

TecnobabbleFocal Length (mm) Focal Distance Depth of Field

10 0.5 (1.64 ft) 0.482 (1.581 ft)

20 1.0 (3.281 ft) 0.421 (1.381 ft)

50 2.5 (8.202 ft) 0.406 (1.332 ft)

100 5.0 (16.4 ft) 0.404 (1.325 ft)

200 10 (32.8 ft) 0.404 (1.325 ft)

400 20 (65.62 ft) 0.404 (1.325 ft)

Based on an aperture of F4

Small ApertureAperture value F22

This small aperture opening forces the shutter to stay open for a longer period of time, this allows you to make water seem

silky.

Smaller apertures normally require a tripod

Almost everything in the image is in the same focus as a small

aperture allows for greater depth of field.

Large ApertureAperture Value F5.6

The large aperture opening allows a great deal of light into

the camera in a very short period of time, as such, the

shutter speed will be increased significantly.

Backgrounds are normally blurred with large apertures as

the shutter isn’t open long enough to capture all of the

reflected light and detail

Large apertures can be used easily for hand held shots

Mid-range ApertureAperture value F8

Mid-range apertures will allow you to have greater depth of

field while still blurring some of the background.

This can be useful when you are trying to capture larger

groups of people, or there are subjects of interest in the

general proximity of your main subject.

Aperture F13I chose F13 for the relatively

deep depth of field, however I didn’t want the shutter open so long as to make the waves in

the background blur.

Good texture in the foreground and lighthouse in acceptable focus in the background gives

the person viewing the image a sense of the location and time

of year.

Darker lighting and dark clouds set the mood.

Aperture F5.6Applied a shallow depth of field

on this shot to isolate my primary subject.

I wanted to show the male to be ever vigilant while the

female was feeding.

Female and background are blurred, foreground is limited in

focus.

Male in sharp focus with light reflection in his eye.

ApertureQuestions?