Tuesday, May 17, 2011

Class #4

Lenses.....Part Two!- For this class we covered Depth of Field with the lens.  Depth of Field is the amount of an image that is in focus in front of and behind the main subject.  This is important in creating image composition.....the viewer's eyes will only want to stay in areas that are sharply focused.  We can alter depth of field three ways.....

1. F-stop - The larger the f-stop (smaller the number) the shallower the depth of field, while the smaller f-stop (bigger the number) creates a greater depth of field.  So with a smaller f-stop, objects behind the main subject will appear more out of focus.

2. Lens Focal Length - The longer the lens the shallower the depth of field, the wider the lens the greater the depth of field. 

3. Camera to Subject Distance - The closer you are to the subject the shallower the depth of field, the further away you are the greater the depth of field. 

We covered ISO briefly in our last class.  The ISO is a measure of light sensitivity to your chip.  One down fall of adjusting your ISO is noise.  The higher the ISO, or increase in electricity running through your chip, the increase in noise.  Noise is the chip adding randomly colored pixels in areas that should be black or very dark.  Noise is caused by the low level electrical charge of the chip actually creating ghost information.  Better cameras have less noise, but all cameras will show some noise at certain setting.  Part of this weeks assignment is to determine at what ISO setting we start to experience too much noise with our camera.

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