Film and Sensitometry • The science of measuring an emulsion’s reaction (sensitivity) to light is called sensitometry • The Characteristic Curve The graph that shows a film’s response to light, showing the contrast (gamma), latitude, and speed.
Exposure Latitude • Exposure Latitude is the amount of over - or under - exposure the film stock can tolerate. • The effect of latitude on the image
The Characteristic Curve and Film Speed • The overall degree of sensitivity of a film is expressed by the position of the characteristic curve in relation to the horizontal scale. It is rated by an exposure Index (EI).This value was also called an ASA or ISO • Faster films are more sensitive and have higher EI numbers. 25 EI 50 EI 100 E 200EI 400EI f/4 f/5.6 f/8 f/11 f/16 (notice how f-stops relate to EI values.)
Exposure • Exposure is determined by intensity of light that pass through the lens and the time each frame is exposed to the light. • Exposure = Intensity X Time It is controlled by T-stop and Frame-rate • Other factures that play a role in determining exposure are: Film speed, Lighting, Filter, Shutter Angle
The Film “Look” • Grain • Sharpness • Depth of Field • Exposure Latitude • Color
Filters • Color correction filters • Neutral density filters • Effects filters
Color Correction Filters • Color correction filters are used when shooting tungsten-balanced film of doors or when using daylight balanced color film indoors. • 85 filters: when shooting tungsten-balanced color film out of doors. 85(the most commonly used), 85B, 85C • 80 filters: When using daylight-balanced color film indoors.
Neutral Density Filters • To cut down overall brightness and reduce all colors equally. • When to use ND filters • Most common used: ND 0.3,ND 0.6 and ND 0.9, need to increasing exposure (stops) in 1, 2 and 3 stops
Effects Filters • Diffusion filters, Nets, • Ultraviolet (UV) filters: The filter most often used for cutting haze and slightly warming the scene is the Sky 1-A. If you don’t want to extra warmth of Skylight filter, Haze 1 and 2A can be used • Fog filter • Low contrast filters: produce less halation and less softening than fog filter. (Tiffen Ultra Contrast filter) • Polarizing filter: light striking an object radiates in all directions • Soft contrast filters • Graduated filters