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"ISO" sensitivity ratings for the Panasonic DMC-FZ1000

Doug Kerr

Active member

If we ignore some subtleties, there are two different "ISO" measures of the sensitivity of a digital camera:

• The ISO speed

• The ISO Standard Output Sensitivity (ISO SOS)

Again, if we ignore some subtleties, for all practical purposes, for any given camera and sensitivity setting, the ISO SOS is 1/2 stop less than the ISO speed. Thus, if for a given camera and sensitivity setting, the ISO speed rating is ISO 100, the ISO SOS value is 71.

Basically, the ISO SOS was introduced to provide a way to "bump up" the photographic exposure (combination of aperture and shutter speed) by 1/2 stop while still holding to the "standard" exposure metering equations in the camera's automatic exposure control system. This "bump" was found desirable in order to recognize that modern, sophisticated metering techniques eliminated the need for the 1/2-stop "headroom" built into the traditional "average scene luminance" metering equations. By "eating the headroom", we improve the noise performance of the system.

Some camera manufacturers have today adopted the ISO SOS premise for the sensitivity setting ratings of their cameras, while others continue to use the traditional ISO speed premise. Both are of course valid, assuming that which is involved is clearly identified (not always easy to find).

The Panasonic DMC-FZ-1000

The Panasonic DMC-FZ1000 is a fixed-lens EVF camera with a "one inch" (8.8 mm high) sensor.

So far I have been unable to find, in any of the literature on this camera, whether the "ISO" sensitivity settings are on the basis of ISO speed or ISO SOS.

However, I recently found that this matter is clarified in the Exif metadata in files from the camera. The basis for the "ISO" sensitivity settings is the ISO SOS.

Best regards,


Doug Kerr

Active member
For those interested in further information about this matter, there is a rather thorough article about it.

Best regards,