403On-Camera Flash PhotographyD Third-Party Flash UnitsThe camera cannot be used with flash units that would apply voltagesover 250 V to the camera’s X contacts or short-circuit contacts on theaccessory shoe. Use of such flash units could not only interfere withnormal operation of the camera but also damage the flash sync circuitsof the camera and/or flash.D i-TTL Flash ControlWhen an optional flash unit that supports the Nikon Creative LightingSystem is mounted on the camera and set to TTL, it will operate in i-TTLmode, employing monitor preflashes for flash photography using i-TTLbalanced fill-flash and the like. i-TTL flash control is not available withflash units that do not support the Nikon Creative Lighting System.D Studio Strobe LightingRear-curtain sync cannot be used with large studio strobe lightingunits, as they will not sync correctly.