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The Pentax AF-540FGZ is a high-powered, professional-tier shoe-mount flashgun designed for Pentax SLR and DSLR cameras. With a powerful maximum guide number of 54 (at ISO 100 in metres), it serves as an excellent lighting tool for creative flash techniques, offering comprehensive automatic and manual control.

Key Technical Specifications

Flash Modes: Supports P-TTL (Pre-flash TTL) for highly accurate automated exposures, standard TTL, auto flash with a built-in sensor, and full manual mode with 7 power levels (1/1 down to 1/64). [1, 2]
Bounce & Swivel: Fully adjustable flash head tilting from -10° to 90° and swivelling up to 180° clockwise / 135° counterclockwise for soft, bounced illumination. [1, 2, 3]
Zoom Coverage: Auto-zooming head adjusting between 20mm to 85mm focal lengths (full-frame equivalent), complete with a built-in wide-angle diffuser panel and a pull-out catch-light card. [1]
Advanced Sync: Outfitted for High-Speed Synchronization (HSS), first/second curtain sync, and wireless P-TTL off-camera operation. [1, 2, 3, 4]
Power Source: Runs on 4 AA batteries (Alkaline, Ni-MH, or Lithium Not Included).