Sekonic L-398M manual Adjust luminance range

Models: L-398M

1 36
Download 36 pages 11.02 Kb
Page 32
Image 32

Adjust luminance range

a.Install Lumisphere.

b.Hold meter at subject position, point Lumisphere toward camera and read needle indication. With all lights turned on, adjust main light so that indication becomes 500 footcandles.

c. Set mark to 500 and read

value becomes 16 to indicate luminance range center point. If by experience the required results can be obtained with a luminance range of 16 to 1, a maximum luminance indication of 64 (center point 16 x 4 = 64) becomes the upper limit for desired color reproduction. In this case, the minimum limit becomes 4 (center point 16

=4 = 4). This means that attractive color reproduction cannot be obtained unless the subject luminance distribution is within 4 ^- 64.

d.Exchange Lumisphere for Lumigrid and check if there are any locations on the subject brighter than 64 or dimmer than 4.

Stage 5

Determine correct exposure

Although above Stage 4b includes an exposure value measurement using the Lumisphere, perform correct exposure measurement as a final check. With the illumination controlled as described, this should accurately become F/5.6 1/50 sec. This 5 stage procedure allows full control of all lighting elements.

Closeups

It is essential to increase the exposure value when the subject is closer to the camera than 10 times the camera focal distance. An example of this type of case is with a camera lens focal distance to 50mm and a subject distance of 40cm. The reason for this is the increased image magnification as the subject approaches the camera. When light from the subject passes through the lens and becomes focused on the film, the following relationship exists among film plane illumination, subject brightness and image magnification.

31

Page 32
Image 32
Sekonic L-398M manual Adjust luminance range