Module 1Digital Cameras

Image Capture

Instead of film, a digital camera uses a device called a CCD (charge coupled device).

The CCD is a light-sensitive chip that converts light into a digital (electrical) signal.

The CCD is made up of thousands of individual sensors

that are sensitive to green, red, or blue light.

The sensors are also known as pixels (picture elements).

The CCD is designed to have options similar to using different film speeds (ISO settings). The higher the

number or ISO setting, the greater the sensor's sensitivity to light.

At an ISO of 800 or more, the camera's aperture only needs to be open for a short time in order to create an image, whereas using lower

numbers means that the sensor needs more light to reach it in order to record a properly exposed shot.

CCD Sensitivity

Resolution is explained as the number of horizontal pixels multiplied by the number of vertical pixels.

The more pixels there are, the higher the resolution.

Higher resolution numbers also mean you will get a better quality (detail and focus) print from a certain file. The higher the resolution the more space

(memory) your image requires.

Screen resolution is 72 dpi, but for print the resolution should be above 200 dpi. dpi = dots per inch ppi= pixels per inch

Image Resolution

Underexposure occurs when the sensor does not receive enough light, and overexposure occurs

when the sensor receives too much light.

Correct exposure happens when your photograph has the same range and intensity of tone as

the scene being photographed.

MeteringSensors on the camera measure the amount of light reflecting back off the subject(s), then the camera uses this information

to calculate the exposure – a process known as metering.

All metering systems are calibrated to average the reflected light to an 18% grey. Colors similar

in density (value) to 18% grey are referred to as the

mid-tones, these include green foliage, brown brickwork and concrete.

Many photographers use a grey card as a

middle grey reference that helps produce a

consistent image exposure.

Proper exposure also depends on finding the right combination of aperture (the amount of light allowed into the camera) and

shutter speed (how long the light is allowed to enter the camera).

Aperture and Shutter Speed

Aperture controls the amount of light much like the iris of a human eye, widening and constricting to let in more or less light depending on exposure

needs.

Apertures are shown in f/numbers or f/stops. As the apertures get smaller, the f/stops get bigger.

When viewed in sequence each f-stop lets in twice (or half) the amount of light.

Aperture choice will also change how much of the

photograph that appears to be in focus.

This is referred to as Depth of Field.

Deep D.O.F = small aperture

Shallow D.O.F. = large aperture

Shutter Speed is how long your aperture remains open, and is measured in fractions of a

second.

For example 250 is 1/250th of a second, 2 is ½ (half) a second and 1 is a full second. Again each step is called a stop, and represents the doubling or halving of the amount of light entering the camera.

Shutter Speed can be manually controlled to alter how motion (a moving subject) is captured in your

photographs.

The JPEG (Joint Photographic Experts Group) is the standard image file format for the Internet.

Most digital cameras create this file format for each image taken.

JPEGs are a compressed file format, which allows for easy viewing and storage.

File Formats

It’s best to set your camera to the largest image size and the smallest compression option. This will give you the highest quality image, however it will also means you can store fewer photos on your memory card.

Memory cards initially store your images. Using either a USB cord or a Memory Card Reader you can transfer your images to a computer.

Our Macs will assume that you want to store your images in iPhoto. You can override this by closing iPhoto and navigating to an alternative storage location

Transferring and Storing Files

(i.e. your network folder or a Flash drive) then click and drag the files you wish to transfer. If you store your images only in iPhoto other people can view and alter your images.

Be sure that you copy instead of move the files if you want them to remain on your camera's memory device!

Your Assignments for Module 1

1. Create a new yahoo/ymail account. First try using firstnamelastinitial@ymail.com format. Tell me your username!! I write them down!

2. Create a FlickR account using your new ymail email address. (I have a handout for you that walks you through this.) Tell me this username also—I need it to create our class group!

3. Take a photo of yourself using the Photobooth program. Upload this image of yourself to FlickR Photostream and set it as your “Buddy Icon,” so I can see your face when I grade your photos.

As you are doing this today, I will also be recording your camera info

4. Take a photo (any photo!)

5. Transfer the image from your camera to either your network folder or a Flashdrive. Why not just the desktop?

6. Then upload it to your Photostream.

6. Create a new FlickR Set called: Module 1

Photobooth image of yourself

This set will have two photos

A photo that you took with your digital camera and uploaded to the computer (can be of anything—this is just practice!)

7. Create a new FlickR Gallery called: Gallery 1

You will browse FlickR for other people’s photos and create a gallery of 3 pictures that describe

your summer…

In the Description Field of each picture, tell me what activity this photo describes and why you like this particular photograph

Getting to Know Your Digital CameraReading the Symbols…

"The image on the left was the exposure that the camera calculated for this scene.  The camera wanted to make sure the walls of the tunnel were exposed properly, but as result, the sculpture at the end of the tunnel in daylight is very bright (over-exposed).  By dialing down the exposure compensation to about -1.0, I was able to force the camera to darken the exposure."

Tungsten – This mode is often used while shooting indoors. The tungsten setting of the digital camera cools down the color temperature in photos.

Fluorescent – This mode is used for getting brighter and warmer shots while compensating for cool shade of fluorescent light.

Daylight – This mode is for the normal day light setting, while shooting outdoors. Many cameras do not have the Daylight mode.

Cloudy – This mode is ideal for while shooting on a cloudy day. This is because it warms up the subject and surroundings and allows you to capture better shots.

Shade – A shaded location generally produces cooler or bluer pictures, hence you need to warm up the surroundings while shooting shaded objects.