EXPOSURE WORKSHOP

Today i attended John's exposure workshop, which was to help us learn about camera exposure and how it effects the pictures we take.



Exposure - amount of light received by the sensor.



There are 3 main things to consider when taking a picture these are

• ISO (film speed)


• TIME (shutter speed)


• INTENSITY (aperture)

ISO - International Standers Organisation. film speed, sensitivity of sensor control how fast or how slow it records information.

example - f8 @ 1/125 iso 50 is slower film speed, f8 @ 1/125 iso 1600 is a faster film speed.

ISO's 25, 50, 1oo are slow film speeds, usually higher definition (rich with lots of detail).

ISO's 200, 400 are medium film speeds used for more general use (200 ISO is usually the optimum film speed for a digital camera).

ISO's 800, 1600 are fast film speeds with lower defination (corse and grainy)

How fast of slow light is absorbed, landscape photographers tend to use slower film speeds while sports photographers would use a faster film speed.

ISO CONTROLS -

• SPEED SAND SENSOR (light absorbtion)


• AMOUNT OF DEFINITION (levels)

INTENSITY - APERTURE

F2.8 F4 F5.6 F8 F11 F16 F22

At F2.8 the aperture ring would be wide open and at F22 the ring would be a small hole.

Aperture controls the light that falls on the sensor.

APERTURE CONTROLS -

• INTENSITY OF LIGHT FALLING ON THE SUBJECT


• DEPTH OF FIELD (2.8 low depth - 22 high depth)

TIME- SHUTTER SPEED

• B - bulb 10sec to 1min


• 1/2, 1/4, 1/8, 1/15 - used for landscape, time lapse photography.


• 1/30, 1/60


• 1/125, 1/250, 1/500, 1/1000 - used for sport photography

shutter speed controls the amount of time the shutter curtain is open and light spills in.

SHUTTER CONTROLS -

• TIME ALLOCATED FOR LIGHT TO FALL ON THE SENSOR


• SUBJECT MOVEMENT (to freeze action or not?)

Using any of the above setting with effect the picture in various ways.

INCIDENT LIGHT - the light which falls on to a subject.

REFLECTIVE LIGHT - the light which falls of the subject.

*CAMERAS ONLY READ REFLECTIVE LIGHT*

When taking a portrait its always best to take a reading on incident light. It's very important to shoot to the right of the histogram getting plenty of mid tones means a picture can be edited with out losing and information (quality of picture).