Photography Notes

The following notes are accumulated through my study of Digital Photography.

Aliasing: Pixelation on the edges of lines, shapes, etc.

Moire Pattern: An interference pattern caused by multiple different patterns combined.

Angle of View: Width of an image. The human eye (one eye open) has a 49mm angle of view.

Pixel: Picture Element. A single photo site on a sensor.

Crop Factor: A comparison of a digital sensor with 35mm film (measurement). The smaller the sensor the higher the multiplication factor. E.g. if the sensor is 17mm X 13mm (4/3) then it is half the size of the 36mm X 24mm film dimensions and has a crop factor, or multiplication factor, of 2.0. A 50mm lense in conjunction with a 2.0 CF sensor would produce the same effect as a 100mm lense with a 35mm sensor.

Depth of Field: A function of magnification. Small sensors produce higher magnification than large sensors. As aperture changes, so does depth of field.

Depth of field should be 1/3 in front of the subject and 2/3 behind the subject.

Parallax: The affect of having different angles of incedent from the lense. E.g. having a flash above and to the side of a lense will reduce red eye through a parallax effect.

Diopter: A viewfinder that can be adjusted to the photographer’s eyesight.

Chromatic aberration: inability of a lense to focus red, green, and blue light on a fixed point. This usually occurs around areas of high contrast towards the edges of an image.

Spherical aberration: distortion of focus towards the edges of an image.

Sensor: silicon is sensetive to light when it is charged.

CCD: Charged Coupling Device, 8-bits of information per channel.

CMOS: Complementary metal-oxide-semiconductor. Deeper photo wells, 16-bits of information per channel.

Example photo cell array:

R G R G R G
B G B G B G

The chip has a lower sensitivity to green so more green photo cells are added. Conversely, our eyes have a higher sensitivity to green.

Blooming: Photo sites receive too much light and flare out to neigboring sites.

Noise: When the sensor receives too little light the active charge will create visual artifacts.

Blackbody reference: black cells are scattered throughout a sensor array in order for the software to make adjustments to the image.

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