Digital Photography Basics

Camera Care

Camera Protection

• Use the neckstrap! Cameras are a fragile piece of equipment and all it takes is one slip to ruin an expensive investment. Some wristwatches are impact resistant. No cameras are to our knowledge.
  
• Keep the camera dry. With a few exceptions, cameras are also not waterproof and all it takes is one drop of water in the wrong place for disaster. You probably should not attempt to use your camera in the rain, even with an umbrella. If you need a waterproof camera for underwater work or shooting in the rain, there are waterproof housings available for several SLR's and a couple of high end point and shoot cameras.
  
• Keep the camera covered from dust. Once a camera becomes dusty, it can be difficult to clean the dust from all of the nooks and crannies. You should buy a camera case and use it.

Camera Care

• Get a lens cleaning kit. Do not use any other materials to clean the lens. Loose dust can be removed by gently brushing with a dry lens brush or lens cloth If you perform any cleaning with other materials such as tissue paper or Q-tips, use lens cleaning solution because it acts as a lubricant. Do not use saliva or tap water.
  
• Clean the image sensor (and reflex mirror in the case of SLR's) only when there are foreign objects appearing in your photos and you are sure that they are not the result of a dirty or damaged lens. Preferably this should be done by a camera service department or professional. Otherwise, follow the instructions that come with the camera very carefully. Note that if the defect appears only in the viewfinder and not in the photo, then this is not the fault of the image sensor. Try cleaning the viewfinder and/or reflex mirror.

Supporting the Camera

Movement or shaking of the camera can cause blurring of a photo. For most types of shots you should get good results holding the camera in your hands if you brace yourself and hold your breath when you take the shot (Try it. It helps!). If you are taking shots that need a slow shutter speed such as night or time lapse shots, or are taking telephoto or closeup shots, then a good tripod is a necessity. Do not skimp too much on a tripod because cheaper ones will not provide steady support.

Digital Camera Terminology

• Aperture
  A circular opening behind the lense of the camera that can be made larger or smaller in a similar manner to the iris of the human eye, thereby allowing greater or lesser amounts of light to pass. Aperature is measured by "f-stop" values (see below).
  
  
• Color Temperature
  A measure of the color of a light source is to white light. White light has a temperature of 5500 kelvin. Incandescent light from a typical household bulb has a temperature of about 3200 K.
  
  
• Depth of Field
  Depth of Field refers to the range of distance within which objects are in focus. With a wide depth of field, both near and far objects are in focus. With a narrow depth of field, only the object focused on is in focus. Objects farther away or closer are out of focus.
  
  
• Exposure
  Exposure refers to the total amount of light that reaches the image sensor while a photo is being taken. Overexposed pictures are too dark. Underexposed are too light.
  
  
• Focal Length
  Focal length refers to the distance between the "center" of the lens, and the image sensor of the camera. Telephoto lenses have a long focal length. Closeup lenses have a short focal length.
  
  
• f-stop
  The f-stop setting measures the size of the aperture opening. A large f-stop value represents a small aperture size. A small f-stop value represents a large aperture size.
  
  
• Image Format
  Image format represents the way in which the digital data representing a digital image is stored. There are two types of formats; compressed, and uncompressed. It takes less data (smaller file size) to represent a compressed image than an uncompressed one. Compressed images have lower image quality (depending on format) than uncompressed images. The greater the compression, the poorer the image quality but the smaller the file size. Print media often employs uncompressed images since bandwidth is not an issue. Compressed formats are required for images used on the internet due to bandwidth limitations. The format of an image is identified by the three or four letter codes following the dot in the file name. For example "sunset.jpg", or "logo.gif". Common image formats along with advantages/disadvantages are listed below:
  
  
  • bmp: This extension refers to "bitmap". Uncompressed bitmaps have a very large filesize and as such are unsuitable for use on the internet. This format is not widely used because there are better formats for almost any use.
    
    
  • gif: An older compressed image format that is limited to 256 colors rather than the millions of colors that can be represented by newer formats. Because of this it is not adequate for photographs but is still useful for simple graphics with few colors such as logos or cartoons. Its advantages are that it can represent transparency and images can be animated. The amount of compression can be adjusted with image editing software.
    
    
  • jpeg or jpg: This format is generally the best and most widely used format for photographs for internet use because if offers small file size along with good image quality. The amount of compression can be adjusted.
    
    
  • png: This is a newer format of the the vector type. The big advantage of vector formats versus other types is that images in a vector format can be edited without loss of image quality. Images are often stored and edited in the png format then converted to other another format with greater compression for use on the internet.
    
    
  • tiff: This is also a vector format with the corresponding editing advantages. It is an uncompressed format and as such is unsuitable for internet use, but is widely used for print media. It is the default format for many flat bed scanners.
    
    
  • RAW: This is a type of format available with high end digital cameras. It is uncompressed and is the closest representation to what is "seen" by the camera. It is employed by some photographers because it offers editing options unavailable with other formats, but it must be converted to another format for actual use. Each camera manufacturer uses a different proprietary RAW format.
    
    
• Image Sensor
  This is the electronic component that serves as the "film" of a digital camera. It converts the light that reaches it into electronic data.
  
  
• ISO
  This is the scale used to denote the sensitivity of the image sensor. The image sensor can be adjusted to more sensitive (higher ISO setting) to compensate for underexposure.
  
  
• Noise
  Noise is electronic distortion of the image introduced by the image sensor. It can make a photo appear to be covered with christmas lights! It is a bigger problem for "point and shoot" cameras with small image sensors whose pixels are smaller and/or closer together than for an SLR camera with a larger image sensor.
  
  
• Pixel (Megapixel)
  You can think of a pixel as a dot. All digital images are made up of tiny dots. A computer display set to a common resolution of 1024 X 768 display uses 1024 pixels across and 768 pixels vertically to produce what you see on the screen. A "megapixel" is a million pixels. A 6 megapixel digital camera produces an image with 6 million pixels. As you can see, that is a very large image compared to what can be displayed on the computer screen. Such large images must be reduced in size using image editing software before they are practical for use on the internet. Print media uses similar dots to produce images. In the world of print media the dots are called "dots" and the resolution of a printed image is denoted by dpi (Dots per Inch). A 6 megapixel camera can produce a printed image comprised of 6 million dots.
  
  
• Reflex Mirror
  This mirror is what gives an SLR (Single Lens Reflex) camera it's name. It is a small mirror whose purpose is to direct the image from the lens to the viewfinder. It moves out of the way when the shutter button is depressed.
  
  
• Shutter - Shutter Speed
  The shutter is the device that either permits or blocks the passage of light to the image sensor. On some cameras the shutter is a mechanical door that lifts out of the way when the shutter button is depressed to take the shot. The shutter speed refers to the amount of time that the shutter remains open when the shot is taken. Too slow of a shutter speed results in overexposure because it allows too much light to pass to the image sensor. Too fast of a speed results in underexposure because too little light passes.
  
  
• SLR
  Single Lens Reflex camera. This is the type of camera used by professional and serious photographers. It uses interchangeable lenses and has more controls and a larger image sensor.
  
  
• Viewfinder
  The "eyepiece" of the camera that you look through when you take shot. Some cheaper point and shoot cameras do not have viewfinders.
  
  
• White Balance
  The control that adjusts the color that represents true white to the camera. This control is sometimes used to adjust indoor shots to adjust for illumination by artificial lighting that is not pure white light, such as that produced by household incandescent bulbs.