Lesson 4 : 15.3.2010 - Shutter Speed, Aperture and D.O.F

Lesson 4 : 15.3.2010

Shutter Speed, Aperture and D.O.F

The Ideal Shutter Should
- expose each part of the film/sensor equally and simultaneously
- be silent in operation
- be vibration free
- little effort to set in motion
- effective exposure should be repeatable

Focal Plane Shutter
- flash should only operate when shutter is fully open
- flash synchronisation is therefore limited
- In order to achieve very fast speeds the second curtain is released soon after the first to follow it across the shutter window or gate as a slit

Between The Lens or Leaf shutter
- maximum speed of 500th sec due to mechanical limitations
- synchronises with electronic flash at ALL speeds
- most medium format cameras
- accuracy is affected at high speeds and when particular apertures are chosen
- shutter opens and closes at the same rate regardless of shutter speed chosen
- shorter time to uncover a small aperture
- longer time to uncover a large aperture

Depth of Field Definition
The region of acceptably sharp focus around a subject position, extending toward the camera and away from it, from the plane of sharpest focus. The boundaries of depth-of-field are referred to as the near limit (d1) and the far limit (d2).

Controlling D.O.F
Depth of field is increased by:
- using smaller apertures
- using larger subject distances
- using wider angle lenses