Canon 77D Flash

Coverage and Range
Good flash range, though with narrow and uneven coverage. Above average flash exposure compensation required.

Coverage. Canon rates the EOS 77D's internal flash coverage at approximately 17mm, though as you can see in the above shot taken at 18mm, we've found manufacturers' coverage ratings are usually quite optimistic. Peripheral Illumination Correction was on (by default) for this shot, so the fall-off seen here in the corners and vertical edges is mostly from the flash itself. Coverage is also a little uneven vertically, with a couple of dimmer horizontal bands. We doubt you'd notice this in most real-world flash shots, though.

Exposure. Indoors, under incandescent background lighting, the Canon 77D's flash required +1.0 EV flash exposure compensation for our standard shot at f/4 at ISO 200, and it used a shutter speed of 1/60s which is good. Auto white balance was however quite cool. Letting the camera choose the ISO produced a very warm image at ISO 1600 because of the stronger influence of the ambient lighting.

Manufacturer Specified Flash Test. The Canon 77D's built in flash has a rated Guide Number of 12 meters or 39.4 feet at ISO 100. That works out to a distance of about 9.8 feet at ISO 200 and f/5.6. In the shot above at those settings, we can see that the Canon 77D's built-in flash performed to specification, producing a well-exposed flash target at the rated distance.