lenes

zoom lens





A zoom lens is a lens that allows the photographer to take images with a varied focal length and the angle of view.





Telephoto lens





the length of the lens is shorter than the focal length





Wide Angle lens





are wider than the human eye and have





Retro focus lens





is a reversed of a telephoto lens





Quasi Fisheye

is a extreme wide angle lens that is more than 100 degrees, depth of field is infinite

fisheye

the lens produces an image that is 180 degrees, this repersented as a circular image.

Catadioptric Lens

this lens uses reflected and refracting surfaces on the lens to form the image

Macro Lens

for a macro lens it is able to focus on a subject that is very close, and the depth of field is very small

Teleconverter Lens

is a conection that is added to the camera and it increases the focal length

Close Up Filter (lens)

is a filter that can be used macro work, it acts as reading glasses and enlarges the image

Tilt Shift Lens

are mostly used for architectal photography but can be used in making miniature photography

Long Focus Lens

acts as a telescope and makes subjects that are far away close, this is ideal for wildlife shots

class 29/3

Crop Factor

full frame sensor is 24mm X 36mm - which is the same as a 35mm camera

*it is full frame
then 1.3 1.5 1.6

crop factor relates to the cropping of the angle of veiw as a result of the smaller sensor

eg -- if had a 200mm lens with a crop factor of 1.5 - it turns out to be effectively a 300mm

200mm X 1.5= 300

class 22/3

CCD or CMOS

The first digital sensor was CCD, but lately most have been replaced by CMOS. The reason is mostly because of the price and the CMOS uses less power then the CCD. CMOS is able to produced much cheaper than the CCD sensor, the reason that they can be preduced cheaply is because they can be made at any silicon production line. The CCD have different advantages such as having less noise and more uniform output.

class 15/3

DOF

DOF is region acceptably sharp in focus around a subject postion, extending towards the camera and away from the plane of the sharpest focus. The DOF isn changed with the f-number that is used, (f22 give more in fouces but lets less light in - smaller hole, f1.8 on the other hand is very shallow but lets lots of light in).

exposure

In photo tech the class it was about exposure and if you changed the f-number or shutter speed, then the exposure would remain the same if they are both changed.

So if had 400 ISO f22 and 1/125^th

(Can only shot at 500^th)

The new exposure would be

100 ISO f5.6 and 1/500^th

(The class was the 1/3/10)

photo tech - class 22/2

In class we learnt about the basic history of photography, how the obscura was first used by Arab scholars in about 10^th century. In 1558 it went from a device that saw the outside surroundings to a device that aided with drawings when a mirror and lens was added. This made it easier to portray “life like images”; Johannes is considered to have used a camera obscura in his paintings. In 1826 Niepce is considered the first person to capture a permanent image

(The exposure was 8 hours)