ARISTIMU_O

VIDEO PRODUCTION

| the camera |




VIDEO PRODUCTION :: THE CAMERA

 

BASIC PRINCIPLES OF PHOTOGRAPHY
"Camera" is the Latin word for ROOM

Think of a camera as a room with a pin-hole opening at one wall and a light sensitive surface on the opposite wall. An image outside the room will be projected through the pin-hole (which in real cameras are lenses) and will make an EXPOSURE on the light sensitive surface.

TO get a PROPER EXPOSURE, you have to consider these 4 basic factors:

1.     APERTURE

2.     SHUTTER SPEED

3.     SENSITITIVY OF SURFACE (FILM or CCD CHIP)

4.     AMOUNT OF LIGHT IN SCENE

SEE HOW CAMERAS WORK_
SEE HOW CAMCORDERS WORK (SEE BASIC COMPONENTS DIAGRAMS)

LENSES
___ FOCUS
___ APERTURE
___ FOCAL LENGTH
___ DEPTH OF FIELD

 


LENS CHARACTERISTICS (aperture, focal length)

Lens: Glass elements contained inside a tube or barrel. These elements (lenses) actually focus a projection of the image in front of the camera unto a light sensitive surface located just behind the lens (film or CCD chip)

APERTURE : opening of the IRIS

·       Measured in F-Stops

·       Higher f/stop, closed iris. less light gets in, MORE Depth of Field


Lower f/stop, open iris, more light gets in, LESS depth of Field


FOCAL LENGTH - the length of the lens (technically the distance between the center of the lens and the light sensitive film unto which the lens projects)

·       Prime lenses (fixed focal length) vs._ zoom lenses (variable focal length)

·       Focal length determines how narrow or wide the viewing range or field of view
_

SHORTER LENS

LONGER LENS

Wider Angle_

Telephoto - Narrower angle

More in Picture

Less in Picture

Smaller Subject_

Bigger subject

Greater distance between subjects

Optical "compression" of distance

Space is "Expanded"

Space is compressed

More/Deeper Depth of Field *

Less/Shallow Depth of Field*

* This is an illusion

HOW TO FOCUS ::
Critical Focus: Zoom all the way in and then focus, then you'll be focused for the whole range of lens

LENSES: DISTANCE, SPEED PERSPECTIVE (opens external site tutorial)

Depth of field
_

CONTROLLING DEPTH OF FIELD

(1)__ Change the size an object appears in the image

  • Larger an object is reproduced, the less depth of field.
  • You can make an objects appear larger by moving the camera closer to the subject or by changing the focal length of the lens (zoom or telephoto).

 (2)__ Change the f-Stop

STOPPING DOWN THE F-STOP (a smaller aperture _higher f-stop number)__ increases depth of field

BUT BECAUSE YOU ARE LETTING IN LESS LIGHT, YOU'LL NEED TO:_

1._Add light to subject
2. Use slower shutter speed


STOPPING UP the F-STOP (bigger aperture _lower f-stop number )_
decreases depth of field.

BUT BECAUSE YOU ARE LETTING IN MORE LIGHT, YOU'LL NEED TO:

1_ Use faster shutter speed
2_ Lower light
3_ use ND filter

_

TO MINIMIZE DEPTH OF FIELD:
________ Open iris (lower f-stop number)
Or
________ Move closer to subject
Or
________ Use a longer focal length lens

TO MAXIMIZE DEPTH OF FIELD
________ Close Iris (higher f-stop number)
Or
________ Mover farther from subject
Or
________ Use Shorter Focal length lens

KEEP IN MIND THAT closing or opening the iris will affect your exposure and you will need to compensate for the amount of light lost or gained by

  • Adding/decreasing light
  • Using filters to decrease light getting to CCD sensor (or film)

 

 

F-STOPS AND CREATIVE FOCUSING TECHNIQUES,

including Selective Focus, and problems with Auto-Focus.

Open external site for detailed explanations

 

 

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VIDEO PRODUCTION