14b E-950 E-800 E700 Digital Camera Tutorial : Sensitivity

Intro | Metering | Sensitivity | Exposure Compensation | Image Adjustment

Sensitivity

The sensitivity control may be thought of as being equivalent to putting different film with different ISO ratings into the camera. This has the effect of shifting the combination of Aperture and Shutter speeds so that, for a given exposure measurement, the shutter can be set faster, or the aperture can be set smaller as the sensitivity is increased. Under normal shooting conditions, increasing the sensitivity will not affect the exposure of the image.

However, under low-light conditions, for example when shooting interiors where flash is not allowed, the increasing sensitivity can bring the shutter speed up to a value where a useable image can be obtained.

The table below gives an example of Shutter/Aperture combinations, showing how increasing the sensitivity results in a faster shutter speed:

Shutter Speed	Aperture	Sensitivity
1/15	f 2.6	Default
1/30	f2.6	+1.0
1/60	f2.6	+2.0

Example
The image  shown below is an architectural model which was enclosed in a glass cabinet. It was located in museum and was illuminated with a low power incandescent bulb. It was not possible to use flash due the the glass cabinet and museum rules. The shutter speed is 1/54th with focal length equvalent to about 70mm.

With sensitivity set to "def" (ISO80 equivalent) the shutter speed was only 1/4 sec and the image was unuseable due to camera shake, as the lower inset image shows.
With the sensitivity at +2, the shutter speed rose to 1/16th and the clearer image was produced as shown in the upper inset.

Intro | Metering | Sensitivity | Exposure Compensation | Image Adjustment