Photograph Tech for AAU

A Technical Introduc1on to Photography

Ida C. Benede9o Addis Ababa University January 13, 2010

This presenta1on covers: Basic technical aspects of exposure and image post-‐produc1on

This presenta1on does NOT cover: Composi1on, aesthe1cs, ethics, and visual storytelling.

Photography is ‘light wri1ng.’

Neil Selkirk

Light

Source Intensity Quality Color

Direct Sunlight

Constantine Manos

Oblique Sunlight

Overcast

Steve McCurry

Twilight

Alex Webb

Ar1ficial, Mul1ple Sources

Jonas Bendickson

Ar1ficial, Single Source

Alexandrea Boulat

Exposure is measured in stops.

Double the light is +1 stop.

Half the light is -‐1 stop.

Underexposure – not enough light loss of detail in shadows

Overexposure – too much light loss of detail in highlights no true blacks

The in-‐camera light meter will tell you if your seZngs will result in a properly exposed photo or not.

You have three tools to control light exposure;

ISO, Shudder Speed, and Aperture.

ISO measures how sensi1ve the photographic plane(either a digital sensor or film) is to light. ISO is also referred to as film speed.

The lower the number, the less sensi1ve the photographic plane is to light. The typical range of ISO is 50 to 3200.

With higher the ISO (more sensi1ve to light), the photograph will have more grain or digital noise.

Shu9er Speed indicates how long the shu9er is open for each exposure.

Shu9er speeds are measured in frac1ons of seconds or whole seconds.

Slower shu9er speeds will result in mo1on blur in the photograph. For hand held shots, shu9er speeds slower than 1/60 are likely to be blurry.

Aperture indicates how wide the shudder will be open during the exposure.

Aperture is measured in f-‐stops. The lower the number, the wider the aperture opening.

The photograph’s depth of field is effected by the aperture. Large apertures (small f-‐stop #) result in shallow depth of field. Small apertures (big f-‐stop #) result in large depth of field.

TV -‐ Shu9er Speed Priority

AV – Aperture Priority

M – Manual

You want to freeze mo1on.

100 ISO -‐ f5 -‐ 1/500

100 ISO -‐ f2.8 -‐ 1/500

You want mo1on blur.

100 ISO -‐ f/11 -‐ 1/50

100 ISO -‐ f/8.0 -‐ 1/60

400 ISO -‐ f2.8 -‐ 1/500

You want everything in focus.

600 ISO -‐ f8 -‐ 1/60

You want a few people in focus.

600 ISO -‐ f2.8 -‐ 1/500 or 200 ISO -‐ f2.8 -‐ 1/60

You want a the subject to be crisp.

1000 ISO -‐ f2.8 -‐ 0”2

Good luck…

Two more things to keep in mind…

Focal length indicates the lens’ the degree of magnifica1on and the angle of view.

Focal length is measured in degrees. The smaller the number, the lower the magnifica1on and the wider the view.

Since the focal length effects angle of view, the shape and posi1on of objects will differ at different focal lengths.

Color temperature is the color of the light based on various ligh1ng condi1ons.

Color temperature is measured in kelvins ranging from 1000 to 9300.

Our eyes automa1cally adjust for color temperature. Digital cameras do too, but not as well. Color temp. can be corrected or accentuated in post-‐produc1on.

Now ask some ques1ons.

Then, go experiment.

Ida C. Benede9o www.idaimages.com [email protected]

This presentation is licensed Creative Commons.

Photograph Tech for AAU

Technology

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