Assignment- HighKey & LowKey

HIGH-KEY Is a style of lighting for photography that focuses on reducing the lighting ratio present in the scene. High-key images often have white or washed out backgrounds, and often time the images loose detail in the highlights.
One way to achieve this effect is with multiple light sources (mainly from the sides and back of the image). Back-lit images can also be high-key.

Richard Avedon, a hugely influential and successful fashion and portrait photographer, often photographed with white backgrounds. Some of his images could be considered more high-key.

LOW-KEY Is a style of lighting for photography where the overall image is dark and typically the light source is only one key light. Low-key images have dark backgrounds or they are darker overall. Sometimes photographers use a reflector to fill in some of the shadows, if anything is used at all. Please note that you do not need to only use unnatural sources of light to achieve a low-key image. Sally Mann made Low Key images in natural lit situations by finding and using intense areas of shade and by completely controlling the elements of exposure.

images by Sally Mann

Exposure- Exposed

When correctly exposed, a photograph will have an entire spectrum of values
Highlights ... Shadows ... Medium values

image by Ansel Adams, a master of exposure.

THE ZONE SYSTEM

Ansel Adams, along with Fred Archer, formulated a technique which they termed the Zone System. It is a method which assists the photographer in calculating the most precise exposure to any given circumstance.
A photographer knows the difference between freshly fallen snow and a black horse, while a meter does not.
The Zone System assigns numbers from 0 through 10 to different brightness values, with 0 representing black, 5 middle gray, and 10 pure white; these values are known as zones. (source: Wikipedia)

Your internal camera meter renders the middle value/tone of the over all image. This is another reason (besides white balance) why I recommended you all obtain a gray card. Have you ever taken a picture of a person in all black or in all white and the photo turned out to be too light or too dark? This is because your camera keyed into the light reflecting off the the black (or white) and rendered it as medium gray instead of black (or white).
The Zone System provides a straightforward method for rendering these objects as the photographer (YOU) desires, and not as the internal camera meter dictates.
Using your gray card, you can guarantee that you’ll have each value fall where it should (either on the shadow end or the highlight end).
Place your gray card in front of your subject, with the same amount of light falling on it as your subject. Now use your gray card to determine the correct exposure for your photo- keeping an eye on the internal light meter in your camera. Your gray card will help you obtain the correct combination of your shutter speed and aperture for the image to be accurately exposed. At this point, you can take one picture with the gray card still in the image for post-processing white balance customization. And now, having your exposure set you can start shooting. If, at any point, your light source or direction/amount of light changes, you'll want to revisit your exposure and meter again so that you're accurately exposing every frame.

Suggested workflow:
Set your ISO
Choose your meter mode (you can adjust this, refer to your user manual or use google to figure out how to make these specific adjustments on your camera). I recommend using the "spot meter" mode.
Set your camera to “M” mode
Place your gray card in your scene facing the lens
Take a meter reading by pressing the shutter button halfway
Pay attention to the internal meter reading, adjust your camera so that the exposure bar is in the middle
Compose your subject, making sure that your exposure adjustments haven’t changed
Focus and take the picture
Take one version of the photo with the gray card in it (for accurate white balance readings) and another without the gray card

Key Terms
Underexposure: Too little light or too dark
Overexposure: Too much light, washed out, too light

REMEMBER: You will always get the best results if you start off by making an accurate exposure!!!

Now that you have the necessary tools, you can begin to manipulate scenes to achieve various results that shooting on “auto” wouldn’t give you. You can use your knowledge of metering, shutter speed, aperture, ISO, and white balance etc to be able to render a mood to your photographs that you wouldn’t have been able to other wise. This is the part where photography can start to be super expressive and fun. Where you will begin to see light and will begin to capture it according to your artistic vision!!

Shutter Speed

The following are a few notes from a lecture given on September 13th, 2012.

The shutter has two main functions
1. It controls time (the length of time/exposure to light the image sensor receives)
2. It controls motion (ie: sharp or blurred)

Additionally, the shutter (like the aperture) controls the amount of light that gets through to the sensor.

Shutter speed is measured in seconds
Or in most cases fractions of seconds. The bigger the denominator the faster the speed (ie 1/1000 is much faster than 1/30) In most cases you’ll probably be using shutter speeds of 1/60th of a second or faster. This is because anything slower than this is very difficult to use without getting camera shake. Camera shake is when your camera is moving while the shutter is open and results in blur in your photos. If you’re using a slow shutter speed (anything slower than 1/60) you will need to either use a tripod or some some type of image stabilization (more and more cameras and lenses are coming with this built in).
Shutter speeds available to you on your camera will usually double (approximately) with each setting.
As a result you’ll usually have the options for the following shutter speeds – 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8 etc. This is good to keep in mind since aperture or f/stops also double the amount of light that is let in. This is important to keep in mind because knowing how shutter speeds and apertures relate will give you the ability to adjust both for desired effects in your photography. Something that regular camera-hobbyists don't necessarily know.

When considering what shutter speed to use in an image you should always ask yourself whether anything in your scene is moving.
...and how you’d like to capture that movement. You can freeze the moment or let the moving object intentionally blur (this gives your photographs a sense of movement).

To freeze movement in an image:

You’ll want to choose a faster shutter speed
and to let the movement blur
You’ll want to choose a slower shutter speed.
The actual speeds you should choose will vary depending upon the speed of the subject in your shot and how much you want it to be blurred.

Remember that thinking about Shutter Speed in isolation from Aperture and ISO is not really a good idea. As you change shutter speed you’ll need to change one or both of the other elements to compensate for it.

image found here.

Understanding Aperture and Depth of Field

The following are a few notes from the lecture given on September 6th, 2012:

image found here.

“The camera lens is an array of optics, called lens elements, in a barrel-shaped package, positioned on the front of the camera body.” (pg49, Digital Photography: A Basic Manual. Henry Horenstein)

Aperture:
Focuses the subject
Controls the amount of light that gets through to the sensor
Determines what will be included in the picture
Establishes the depth of field
Opening in the lens created by a series of overlapping blades
Adjustable
Controls the amount of light reaching the sensor
Controls depth of field
Also known as f-stop

F-stop:
F-stop refers to the measurement of the size of the aperture
It represents the relationship between the size of the lens opening and its focal length.
It is derived by dividing the measured diameter of the lens opening by the focal-length.
F-stop numbers seem counter-intuitive because the higher the number, the smaller the opening. For example: f/16 lets in much less light than f/4

Depth of field:
“Range of acceptable sharpness in an image—from the closest to the farthest part of the scene.” (pg69, Digital Photography: A Basic Manual. Henry Horenstein)
Deep Depth of Field: Everything is in focus from front to back of image
Shallow Depth of Field:Sharply focused subject but blurry foreground or background
Depth of field can provide a very selective focus and is determined by the aperture
f/1.4 = Shallow Depth of Field
f/16 = Deep Depth of Field
Depth of field is also determined by Focusing distance
For example: 20 ft from subject vs. 5 ft from subject will affect depth of field
Depth of field is also determined by the Focal Length
Short focal length = ability to have deeper depth of field than a longer lens (ex: 24mm vs 200mm)

A few examples of Shallow and Deep Depth of Field:

images by Carolee Beckham