Olympus E-M10 Flash

Coverage and Range
A weak built-in flash with narrow coverage.

Coverage. Flash coverage was quite narrow and uneven with the kit lens at wide angle (14mm), though some of the corner shading is from the lens itself. Coverage is more uniform (albeit dimmer in the above test) at full telephoto (42mm).

Exposure. In our Indoor Portrait flash test, the Olympus E-M10 underexposed our subject, even with +1.0 EV flash compensation. The camera's Slow-Sync flash mode produced much better results at +0.7 EV aided by the slower 1/6 second shutter speed, though with a stronger orange cast from the ambient room lighting.

ISO 200 Range. Flash exposure started out a bit dim at 6 feet at wide angle, but exposure actually got a bit brighter at 7 feet, then began to fall at 8 feet and got dimmer from there on. At full telephoto, flash exposures started out quite dim and became dimmer as distance increased, so range is less than 6 feet.

Manufacturer Specified Flash Test. The Olympus E-M10's built-in flash has a Guide Number (GN) of 8.2 meters at ISO 200. That works out to about 7.7 feet at f/3.5 and 4.8 feet at f/5.6, the maximum aperture of the 14-42mm lens at wide angle and telephoto respectively. In the shots above (apologies for the out of focus telephoto shot), the E-M10 did not quite perform as Olympus says it will, producing slightly dim exposures at the rated distances (just under 1/4 EV underexposed at wide angle, and just over 1/3 EV underexposed at telephoto).

Our standard test method for flash range uses a fixed setting of ISO 200 (when supported), 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, to assess the validity of the specific claims.