Aperture

The size to which the lens opens. This opening determines how much light will land on the film. Aperture is either fixed or adjustable depending on the camera. This value is often easily found on the lens itself.
Aperture is written in f/# format. (ex: f/2.8, f/5.6). The aperture is approximately 1/4 of the focal length. Therefore, f/16 is a smaller aperture than f/4.

Autofocus

Autofocus (AF) is a system where the lens automatically focuses.

Depth of Field

Aperture affects the depth of field for given picture given that your distance from the subject and the focal length are fixed (as these factors affect depth of field as well). For example, f/4 will offer you a smaller area of sharpness than f/16. For example, this image has a small depth of field (small area of sharpness) because it was taken with a larger aperture.

Exposure

Exposure is the amount of light that your film or sensor is exposed to. Aperture and shutter speed determine the exposure. An example of good exposure: An image with the right amount of exposure will have a good amount of contrast between bright whites and dark values without a loss of details due to too much or too little light in the image. An underexposed image: An image with too little exposure will eliminate details and lack bright white values. An overexposed image: An image with too much exposure will... (more)

F-number or F/stops

This is the way that aperture is written. The aperture is approximately 1/4 of the focal length. Therefore, f/16 is a smaller aperture than f/4. The scale is written in multiples of 1.4 (i.e.- 1.0, 1.4, 2, 2.8, 4, etc).

Focal Length

Focal Length indicates the distance from the optical center of the lens to the film or focal point usually measured in millimeters. (ex: 50mm, 100mm, 300mm) A shorter focal length will give you a smaller area of sharpness whereas a longer focal length will give you more sharpness across the whole image. An example of an image taken with a shorter focal length: A shorter focal length will give you an image like this with small areas of sharpness and other blurry areas. This image has a sharp foreground... (more)

GIF

GIF or Graphics Interchange Format, is an 8-bit perpixel bitmap image format that utilizes a 256 color palette and lossless image compression (the file size can be reduced without harm to the image quality). GIF file formats also support animation but are typically not used for color photographs which often require more than the 256 color palette.

JPEG

Joint Photographic Experts Group (JPEG) is a universal compressed image file format. JPEG’s compress the color and fine detail aspects of photos. Often, the compression made is barely distinguishable from the much larger, uncompressed original.

Lag Time

The time difference between the shutter being pushed and the camera capturing the image.

Lens Mount

The lens mount determines what kinds of lenses are compatible with a camera body. For example, if your camera has a Pentax K lens mount, then only lenses that are indicated to be Pentax K compatible will fit on this camera.
If the lens mount is fixed, this means that you cannot put a different lens on your camera.

Macrophotography

Macrophotography is taking pictures of items close up. Essentially, macro photographers want to depict objects at their life size or larger.

Maximum Aperture

This is the largest aperture for a given lens and is also know as the “lens speed.” If a camera has a large aperture i.e. f/1.4, this means that this “fast” lens is well suited to capture action or night shots because you can use a very fast shutter speed and due to the large aperture still acquire an adequate amount of exposure. *Remember that a large aperture is a small number because it is a fraction - 1/4 of the focal length.

Megapixels

1 megapixel is equivalent to 1 million pixels. The number of megapixels determines the number or sensor elements for digital cameras. For example, a 3.1 megapixel camera, will produce an image that is 2048 x 1536 pixels. (2048 pixels x 1536 pixels = 3.145.728 total pixels) The more megapixels a camera has, the more detailed an enlargement will be from the images.

Normal Lens

Typically a lens of 50mm (in a 35 mm-format camera) This type of lens portrays a subject similarl to our naked eye view (i.e. without magnification)
Canon EF 50mm f/1.4 USM

Noise

Noise is the appearance of color speckles on an image where there should be none. This often occurs when shooting at high ISOs and longer exposure times.
Here is an example of an image with evidence of camera noise:

PNG

PNG is a bitmap image file format used to prevent loss in data due to file compression. PNG files are often used for distribution of images on the internet but the images must be in RGB or grayscale format (not CMYK, etc.). Unlike GIF image files, PNG's can be used without a patent.

Prime Lens

Prime lenses, unlike zoom lenses with adjustable focal lengths, have a fixed focal length.
Canon EF 100mm f/2.8 Macro USM

RAW

RAW files are those that are unprocessed even by the camera itself. Therefore, you must edit these files in special software to achieve a fully developed image.

Sensitivity

The Sensitivity or ISO is a number that indicates the sensitivity of the camera sensor to light. The higher the number, the less light is needed to capture an image. Many cameras offer auto ISO that selects the ISO speed according to the brightness of your selected image. Others allow manual selection. Lower ISO requires more light but the image will produce less noise than at higher numbers ISO. However, keep in mind that manually changing the ISO will also change the aperture and shutter speed of your camera.

Shutter Speed

The shutter speed determines how long the film or camera sensor is exposed to light. The shutter opens and closes for a given amount of time (ex: 1/125 seconds). This in addition to aperture and ISO determine how long the film or sensor for digital cameras is exposed to light. A longer shutter speed will allow for depiction of motion:

Telephoto Lens

A lens with a long focal length (more than 85 mm ). This type of lens makes the subject appear larger in the picture than they did through the naked eye.
Pentax smc P-FA 77mm f/1.8 Limited

TIFF

Tagged Image File Format or TIFF is a universal image file format that is often used in the publishing and publication industry. This uncompressed file format can be compressed by making it into a ZIP file.

White Balance

In order to create accurate color depiction in pictures, cameras often need a reference point of natural white to render the rest of the values in the image. Many cameras offer an “automatic white balance” that attempts to find a white reference in the image and produce the rest from there. Advanced cameras such as SLR digital cameras allow users to find the white reference point from which the camera will produce the rest of the image. Other cameras allow users to select the white balance manually... (more)

Wide-Angle Lens

A lens with a short focal length (less than 35 mm). This type of lens makes the subject appear smaller than it did from the naked eye.
Sigma 30mm f/1.4 EX DC HSM

Zoom Lens

This type of lens allows you to change the focal length without changing the focus of the camera. (ex: an 18-55mm, 70-140mm lenses)
Nikkor 70-200mm f/2.8G ED-IF AF-S VR