Photo U – A Journey into Photography Session 2: Understanding ExposureAlex Santiago

Agenda

What is exposure

Elements of Exposure

Exposure Triangle

Depth Of Field (DOF) Explained

What is Exposure?

Exposure is the process of capturing light in a single shutter cycle to produce an image

Exposure that achieves the effect the photographer intended is “correct” exposure

Exposure is Filling a Bucket…

Think of exposure as filling a bucket with water

Things to consider: Water flow Time to fill the bucket Size of hose (wide/thin) Size of bucket (S/L)

Elements of Exposure

Four Elements of Exposure: Light Aperture Shutter Speed ISO

Each element is crucial in the process to create a photograph

Each element may be used in creative ways

Elements of Exposure: Light

The most important of the elements

Light creates shadows, highlights, textures, accents, moods, emotions, and other enhancing effects on a scene/photo

Finding good light is a skill that comes with experience and a LOT of trial and error

Elements of Exposure: Aperture

Controls the amount of light allowed into the lens

Adjustable and may be made to be larger or smaller

Controls depth of field (DOF)

Elements of Exposure: Aperture – How it works…

Elements of Exposure: Aperture – How it works…

Elements of Exposure: Aperture – How it works…

Elements of Exposure: Shutter Speed

The shutter is a curtain inside the camera that opens for a specified duration of time to expose the sensor/film to light

That duration of time is Shutter Speed

Shutter Speed can be used for effects creation in photographs

Elements of Exposure: Shutter Speed

Shutter speed is used for the following reasons: Determine safe hand

hold speed Stopping action (fast

shutter) Blurring action (slow

shutter)

Elements of Exposure: Shutter Speed – How it works…

Safe hand hold shutter speed to prevent blurry images: Rule of thumb is to

always use a shutter speed equal to the focal length Example:

Lens = 50mmSS: 1/50 sLens: 100mmSS: 1/125mm

Elements of Exposure: Shutter Speed – How it works…

Shutter Speed at 2 seconds

Elements of Exposure: Shutter Speed – How it works…

Shutter Speed at 1 second

Elements of Exposure: Shutter Speed – How it works…

Elements of Exposure: ISO

ISO is the speed with which your digital camera sensor responds to light

Lower ISO setting will require longer exposure time to create an image

Higher ISO setting will capture the same scene with a shorter exposure time

Elements of Exposure: ISO – How it works…

Elements of Exposure: ISO – How it works…

Elements of Exposure: ISO – How it works…

The Exposure Triangle

The Exposure Triangle is a visual representation of the three ingredients needed for a properly exposed image

The relationship between shutter speed, aperture, and ISO is at the heart of all photography

Understanding the exposure triangle will assist you in creating a properly exposed image

Exposure Triangle: Understanding Stops

Aperture, Shutter Speed, and ISO are adjustable

Shutter speed adjustments are done in seconds or fraction of a second

Aperture adjustments are done in f/stops which translate to the size of the lens divided by the aperture Lens size/fstop=aperture

size

ISO Stop Chart f/stops Chart Shutter Speed100 1 1/8000200 1.4 1/4000400 2 1/2000800 2.8 1/10001600 4 1/5003200 5.6 1/2506400 8 1/125

12800 11 1/6016 1/3022 1/1532 1/8

1/41/21"2"4"8"15"30"

Sensitiv

ity

Apertu

re S

ize

smallest

Largest

Fast

Slow

Shutte

r Speed

in S

eco

nds

Slow

Fast

Full Stops Chart

Exposure Triangle: Balancing the Elements of Exposure

When we choose an appropriate combination of shutter speed and aperture size that works, it will not be the only combination

There are multiple correct exposure combination for any scene

The best combination is that which provide the effect intended for the image

Exposure Triangle: Balancing the Elements of Exposure

Let’s look at an example: Aperture: f/11 Shutter Speed: 1/250” ISO: 100

There are several reasons not to use this settings

Determine the rest of the correct exposure values

Hands on Exercise

Depth Of Field (DOF) Explained – What is DOF?

A camera can only focus its lens at a single point

The area in front and behind the focus point that appears to be sharp is the DOF

DOF has an aesthetic and technical impact on an image

DOF enables you to direct viewers to the focal point of an image

Depth Of Field (DOF) Explained – Shallow DOF

Shallow DOF will help you isolate your subject in an image

The objective is to have the subject in focus while having the foreground/background out of focus

Depth Of Field (DOF) Explained – Ingredients for Shallow DOF

Ingredients for shallow DOF Large Aperture Size

(depending on the lens 3.5, 2.8, etc.)

Long Focal Length (70-200 mm, 300mm, etc.)

Lens closer to your subject

Depth Of Field (DOF) Explained – Deep DOF

Deep DOF brings a majority (if not all) of your photograph into sharp focus

Crucial for beautiful landscape images

Require longer exposure time

Depth Of Field (DOF) Explained – Ingredients for Deep DOF

Ingredients for Deep DOF Smaller Aperture Size

(depending on the lens 8,11, 16, etc.)

Short Focal Length (10-24mm, 16-24mm, etc.)

Lens further away from your subject

Questions?