Technical - physical openings control amount of light that hits the film
Creative - controls depth of field (DOF)
Small DOF = small area of focus in image
EX. A portait that isolates the subject from its surroundings (large opening)
Large DOF = large area of focus in image
EX. A landscape image where everything is in focus (small opening)
Small no. = large opening
Large no. = small opening
Shutter
Technical - controls the amount of time that light hits the film
Creative - Depiction of motion
Sync Speed - the fastest shutter speed that can be used to successfully with a flash
Reasonable hand held shutter speed: 1/lens length
Chapter 3
pp. 29 - 33
Definition of Expsure
Film exposure = illumination of image on film x time
Illuminance = amount of light falling on a surface
Luminance = amount of light reflecting from the suface of the subject
Luminance is affect by 2 variables:
- Illumination - the amount of light falling on the subject
- Reflectance -ability to reflect light
Shutter Speed - the length of time the image is allowed to fall on the film
1 1/2 1/4 1/8 1/15 1/30 1/60 1/125 1/250 1/500 1/1000
---> Half the amount of time .......Doubling <---
longer shutter speeds...............faster shutter speeds
more light or exposure..............less light or exposure
slower..............................faster
blur................................stop motion
Each are one stop away from each other
Aperture - a variable opening in the lens consisting of an iris shaped diaphragm. This is controlled by the ring with f-stops on it. It controls the amount of light hitting the film as well as the DOF.
1.4 2 2.8 4 5.6 8 11 16 22
<---Double.........Half --->
more light less light
shallow DOF larger DOF
EX. Equivalent Exposures
Daytime: f5.6 @ 1/125
f2 @ 1/1000
f22 @ 1/8
Night time: f5.6 @ 1/30
f22 @ 1/2
ISO - film speed index. The sensitivity of the film to light
50......100......200......400......800......1600......3200
less sensitive to light...........more sensitive to light
No comments:
Post a Comment