Featuring a large guide number of 54 (at ISO100/m), this clip-on-type auto-zoom flash provides a variety of advanced flash applications, including P-TTL auto flash, high-speed synchronization and wireless P-TTL auto flash, when mounted on a Pentax SLR camera.
Large guide number
Despite its compact dimensions and clip-on design, the AF540FGZ auto flash offers a large guide number of 54 (at ISO100/m) to accommodate a wide range of flash applications.
Advanced auto flash functions
The AF540FGZ features a variety of flash functions, including advanced P-TTL auto flash in which a pre-emission from its spotbeam projector is detected by the camera's light sensor to accurately control the main discharge level needed for proper illumination of the subject. Other functions include TTL auto flash, auto flash, manual flash, high-speed synchronization and wireless P-TTL.
Auto discharge-angle adjustment
When mounted on a Pentax autofocus SLR (after the Z-10 and including digital-format models) equipped with an FA-, FA J-, DFA- or DA- series lens, the AF540FGZ automatically adjusts its angle of discharge to the lens' focal length (automatic function may not be available for certain combinations of a camera body and a lens).