LENSES

Today was focused a lot on light and it's coexistence with the lense.

We know that the speed of light is medium dependant, if it has to pass through a medium it slows down the light.
Hence we know the denser the medium the slower the speed of light.

Refraction happens when light is bent.

We also know that a lens is highly dependant on light as it is a series of prisms designed to bring the light to a single point, which is where we achieve focus.

There are 2 main types of lenses : CONVERGENT (Positive double convex > Looks like an oval)
and DIVERGENT (Negative> Double concave > looks like an apple core)

We also learnt about a thing called circle of confusion which is where the image is soft and out of focus.

FUNDAMENTALS OF THE FOLLOWING LENSES:

*Wide Angle : Allows you to fit a lot of things into the image. Distance between objects is stretched.
* Zoom : Makes objects that are far away appear closer. Can change focal length quickly.
*Long Focus : Takes long distance shots with more in focus.
*Telephoto : Allows you to zoom in more. Making distance objects appear closer and magnified.
*Retro Focus : Opposite and inverted version of a telephoto lens.
*Quasi Fish Eye : Covers the entire frame (Not circular)
*Fish Eye (Circular) : Produces a circular image of a wide frame
*Catadioptric : Uses a mirror to shift focus by reflecting and retracting
*Macro : Used to make macro objects appear bigger. Used close up.
*Teleconverter : Similar to a telephoto lens. Enlarges the centre part of an image by being placed between the camera and the lens.
*Supplementry : Placed in front of the lens to enhance close ups.
*PC/Tilt-shift lense: PC stands for perspective control, hence is a lense that allows the photographer to change the perspective of the image by shifting tilt.

DIGITAL SENSOR ARRAY

Basically today's lesson was about digital sensors array...

We learnt that LARGER = more photosites > more resolution
and SMALLER = more compact > cheaper

A full frame sensor: 24mm x 36mm
And smaller sensors: Defined with a crop factor (cropping of the angular view as a result of smaller sensor; effective focal lengh of lens is magnified by crop factor) cropping angular view.

If noise is constant we know that a smaller site will have a lower signal to noise ratio but image quality and ISO is affected.

We also learnt about blooming which is the loss of subtleties of different readings, so photosites spill over to other areas of the image and the image is affected. You lose highlights.


SLR = Subject luminance range
FILM = Known as density range

Digital Capture

This lesson we learnt about digital sensor arrays

"A digital sensor is a device that responds to different levels of light by producing an electronic signal in proportion to the amount of light"

There are two main types:
CCD (Being Charged Couple Device) and CMOS (Being Complementary Metal Oxide Semiconductor)
The have many differences and can be contrasted and compared in many different ways.

CCD:
* Creates less noise
* Has more uniform output
* Is slower
* Uses more power

CMOS:
* Creates more noise
* Has less uniform output
* Is Faster
* Uses less power

Advances in technology have seen that the CMOS sensor array type has become the preferred type.

We also learnt about RGB (Red Green Blue) and CMY (Cyanne Magenta Yellow)

CY=G
MY = R
CM = B

We also learnt that photosites are the pixel opportunities within an image.

15/3

This lesson we learnt that the ideal shutter is not technically possible.

In a focal shutter plane the flash should only operate when the shutter is fully open hence the flash synch is limited.

We also learnt about depth of field.
Boundaries of depth of field are referred to as D1 (For the near limit) and D2 (for the far limit)
Subject distance (u) refers to the distance from the camera to the subject...

We need to remember that the larger the aperture = the shallower the depth of field.

To INCREASE your D.O.F you need to *Use a smaller aperture
* Use larger subject distances
or * Use a wider angle lense

F4 = Shallow F32 = Deep.