Pentax K-70 Flash

Coverage, Exposure and Range
A fairly powerful pop-up flash with somewhat narrow coverage.

Coverage. Flash coverage was a bit narrow at wide angle (18mm), with dark corners and edges, though we've seen narrower. Intensity also varies vertically, however we doubt that would be noticeable in most real-world shots. We no longer test coverage at telephoto, as it's invariably much better.

Exposure. When it came to exposure, the K70's built-in flash exposed our Indoor Portrait subject well with +0.3 EV flash exposure compensation, which is better than the +0.7 EV flash compensation normally required for this shot. Auto white balance is quite cool, though.

Manufacturer Specified Flash Range. The Pentax K-70's flash is rated with a Guide Number of 12/39 (m/ft) at ISO 100. That works out to a range of about 7 feet at f/5.6. As you can see in the flash range test shot above taken with those parameters using the kit lens, the Pentax K-70 produced a slightly dim exposure (underexposed by about 0.3 EV), indicating the flash output rating is perhaps a bit optimistic. (Note: When we used manual flash at max power, our flash target was well-exposed likely because there is no pre-flash metering which partially drains the flash capacitor, however our standard for this test is auto flash.)

Note: Here we shoot with manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims. The specified range has been calculated for the sensitivity and aperture used in the test shot above.