Lense Types

Wide angle
A lens whose focal length is substantially shorter than an average lens.

Zoom
Lens with the ability to adjust its focal length.

Long focus
Able to take photos of very distant subjects.

Telephoto
A long focal length lens in which the physical length of the lens is shorter than the focal length.

Retro Focus
A wide-angle lens design that uses an inverted telephoto configuration.

Quasi fisheye
Produces an image that covers the entire frame.

Fisheye
A wide-angle lens with an angle of view exceeding 100 degrees.

Catadiptric / mirror lens
A lens where the light bending is done with mirrors rather than lenses.


Supplementary / close up
Used in front of the camera lens to enable it to focus at close range.

Macro
A lens that allows a camera to focus at very close range to photograph small objects.

Teleconverter
A secondary lens which is mounted between the camera and lense to increase the focal length.

PC / tilt shift
A perspective control lens allows the photographer to control the appearance of perspective in the image.

Lenses

Convergent (positive,double convex) and Dirvergent (negative, double concave) lenses

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Angle of incidence and refraction

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Correct viewing distance of an image

VD = F x M

F = focal length
M = magnification

Notes

Ideal Shutter
-expose each part of the sensor equally and simultaneously
-be silent in operation
-vibration free
-little effort to set in motion
-take minimal time to open and close

Between the Lense (BTL) or Leaf shutter
-operates between lense elements
-must be 'cocked' during lense attachment/removal
-max speed of 500th due to mechanical limitations
-syncs with electronic flash at all speeds

Depth of field
The region of acceptably sharp focus around a subject position, extending toward the camera and away from it, from the plane of sharpest focus.
The boundaries of depth of field are refered to as the rear limit(d1) and far limit (d2)

Increasing depth of field
-smaller aperture - greater depth of field
-larger subject distance
-use wide angle lense

Automatic diaphragm
-stays open until shit is taken
-diaphragm closes down to present aperture

Hyperfocal distance
Focus a lens at the hyperfocal distance and everything in the photograph from some near distance to infinity will be sharp. Landscape photographs are often taken with the lens focused at the hyperfocal distance; near and distant objects are sharp in the photos.


Digital capture
uses sensor array types
-CCD (charge coupled device)
-CMOS (complimentary mental oxide semiconductor)

Digital sensor array
-larger size = more photosites = more sesolution
-smaller size = more compact = cheaper
-full frame sensor = 24mm x 36mm
-crop factor relates to the cropping of the angle of view as a result of the smaller sensor
-If noise is consistant then a smaller site will have a lower signal to noise ratio (image quality is affected - ISO is affected)
-small photosite fills - can spill/bleed into adjacent site(blooming)



Dynamic range
-ability of the sensor to record low to high luminances
-SLR = subject luminance range
-known as density range in film
-if photosite overflows it is called 'blooming'