Panasonic GM1 Flash

Coverage and Range
A small, very weak flash with uneven coverage at wide angle. Above average positive exposure compensation required.

Coverage. Flash coverage is rather uneven at wide angle, leaving the corners of our flash target image darker at 12mm, thought that's not unusual, especially for a wider than average kit lens. Some of the corner shading can also attributable to the lens itself. Coverage is much more uniform at full telephoto (32mm).

Exposure. Indoors under incandescent background lighting, the Panasonic GM1's flash underexposed our indoor portrait scene at ISO 200, despite the +1.0 EV flash exposure compensation used. (An average of +0.7 EV is normally needed for this shot.) You'll likely need to boost ISO (or enable Auto ISO) for typical indoor shots. The camera's slow-sync flash mode required no compensation to produce a bright shot, though the longer shutter time resulted in a much warmer cast from the ambient background lighting.

ISO 200 Range. At full wide angle, flash exposures started out a little dim at 6 feet, and brightness decreased with distance from there. At full telephoto, flash exposures started out very dim at 6 feet, and only got darker from there. Very poor flash range.

Manufacturer-Specified Flash Range Test. The Panasonic GM1's small built-in flash has a Guide Number of only 4m at ISO 100, or 5.6m at ISO 200. With the kit lens and ISO set to Auto, Panasonic rates the flash's range at 15 feet at wide angle, and 9.2 at telephoto. As you can see above, the Panasonic GM1 produced a somewhat dim flash target at the rated distance at wide angle (12mm), but results at full telephoto (32mm) are fairly bright. Given the results at telephoto are good, we'd say Panasonic's flash range rating is credible as our wide-angle shot's white ceiling and wall likely influenced metering. Our standard test method for flash range uses either a fixed setting of ISO 200, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera (at Auto ISO if so specified), to assess the validity of the specific claims.