Panasonic GH2 Flash

The Panasonic GH2's built-in flash has a Guide Number rating of 45.6 feet (13.9 meters) at ISO 160, translating to a range of about 11.4 feet at f/4 and 7.9 feet at f/5.8 with the kit lens. That's the same power as the GH1's 36 feet (11 meters) flash at ISO 100, but the GH2's base ISO is 160. The GH2's flash is little weaker than most digital SLRs, which are typically rated at 12 or 13 meters at ISO 100, but much stronger than the GF2's smaller flash, which has a GN of only 20 feet or 6 meters at ISO 100.

The Panasonic GH2's flash is released manually by sliding the Flash Open switch on the camera's top panel forward. Raising the flash enables it. It never pops up automatically like some models, which can be good or bad, depending on your point of view. A novice would probably appreciate an auto-pop-up flash, but someone with experience might think it a nuisance.

When open, the flash doesn't extend very high, so at wide angle longer lenses could cast a shadow, especially when a lens hood is attached. The Panasonic GH2's flash is disabled by pressing down until it clicks shut. The Panasonic GH2 has a dedicated AF assist LED which Panasonic rates as having a range of up to 9.84 feet (3 meters) at wide-angle with either the 14-140mm or the 14-42mm kit lens. AF assist can be disabled in the Custom menu.

The Panasonic GH2's built-in flash has seven modes: Auto, Auto with Red-Eye Reduction, Forced On, Forced On with Red-Eye Reduction, Slow Sync, Slow Sync with Red-Eye Reduction, and Forced Off. Flash modes are changed via the Record or Quick menus, and available settings vary depending on exposure mode. The flash is forced off when closed. A Digital Red-Eye Reduction feature is offered, which when enabled, will attempt to remove red-eye after the photo is taken, via post-processing. A second curtain synchronization mode is also offered. X-Sync (the maximum shutter speed with the flash enabled) is 1/160 second, a bit below average these days, and there is no mention of a higher-speed FP (focal plane) mode. There's also no wireless flash support in the Panasonic GH2.

The Panasonic GH2 allows you to adjust flash and ambient exposure independently of each other, by providing flash exposure compensation between -2 and +2 EV in one-third EV increments. Flash exposure bracketing is not supported, and there is no manual flash mode where output level can be set as a percentage of full power.

Like an SLR, the Panasonic GH2 also has a dedicated hot shoe for mounting external flash units, like Panasonic's DMW-FL500, FL360, and FL220. Olympus flash units such as the FL-50, FL-36, FL-20, and FL-14 should also work, and non-dedicated units can also be used provided they have a compatible trigger voltage and polarity. (Panasonic does not seem to mention the trigger voltage or polarity in the GH2's user manual, though they do warn against using an external flash with "high-voltage" or reverse polarity.)

The advantages of a good external flash are many: more power for increased range, faster recycle times, longer battery life, reduced red-eye, auto zoom to match coverage to the current focal length, and the ability to adjust the tilt and swivel of the head to allow light from the flash to be bounced off nearby surfaces such as a ceiling, for a diffuse effect. Most external flash units have a more powerful AF assist illuminator built-in than the one on the body, and other useful features such as modeling flash are common on higher end models.