Digital Photography Flashcards
digital camera
a photographic device that creates an image of a subject using an optical-electronic system and saves it as a digital file
electronic image sensor
a semiconductor chip inside a digital camera. consists of millions of individual light-sensitive components representing pixels. the optical signal (light) hitting a pixel is converted to an electronic signal and transferred to the buffer.
2 types of image sensors
CCD: directs the electronic signal of each pixel in a complete pixel series to the memory.
CMOS: directs the electronic signal of each pixel to the memory individually/simultaneously (shortens the processing time)
DSLR (digital single lens reflex)
a digital camera that combines the optics and the mechanisms of a single-lens reflex (SLR) camera with a digital imaging sensor. Has a fold-out mirror that diverts an image of the subject to the ocular (viewfinder) lens, to see the precise format/brightness of image before it’s taken.
zoom lenses
focal length can be varied by means of a mechanically adjustable lens system. disadvantage: large proportion of the light reflected by subject is absorbed on its way through the complex lens, meaning larger exposure times and risk of motion blur.
optical vs. digital zoom
Optical zoom uses different focal lengths to enlarge the subject. Digital zoom enlarges only the digital image, which means fewer pixels are used and quality is reduced
focal length
distance between the center of the lens and the focal point (the point at which parallel beams of incident light are brought together), given in millimeters. the lower the values, the greater angle of field.
focus ring
turned to focus the image. changes the distance of the lens system from the image plane so that the most important focal points of the image are on this plane.
aperture
the opening in a lens through which light passes to enter the camera. can add dimension to your photos by controlling depth of field. At one extreme, aperture gives you a blurred background with a beautiful shallow focus effect. At the other, it will give you sharp photos from the nearby foreground to the distant horizon.
depth of field
the amount of your photograph that appears sharp from front to back. Some images have a “thin” or “shallow” depth of field, where the background is completely out of focus. Other images have a “large” or “deep” depth of field, where both the foreground and background are sharp.
large aperture
a large aperture results in a large amount of both foreground and background blur. This is often desirable for portraits, or general photos of objects where you want to isolate the subject.
small aperture
a small aperture results in a small amount of background blur, which is typically ideal for some types of photography such as landscape and architecture.
f-stops
a way of describing the size of the aperture for a particular photo (f/2.8, f/4, f/5.6, f/8, f/11, f/16). the smaller the number, the larger the aperture (it’s a fraction).
shutter speed
the length of time camera shutter is open, exposing light onto the camera sensor. responsible for two particular things: changing the brightness of your photo, and creating dramatic effects by either freezing action or blurring motion.
ISO
a camera setting that will brighten or darken a photo. As you increase your ISO number, your photos will grow progressively brighter. For that reason, ISO can help you capture images in darker environments, or be more flexible about your aperture and shutter speed settings. A photo taken at too high of an ISO will show a lot of grain, also known as noise, and might not be usable. So, brightening a photo via ISO is always a trade-off. You should only raise your ISO when you are unable to brighten the photo via shutter speed or aperture instead. you should always try to stick to the base ISO to get the highest image quality.
