OLOONG Speedlite SP-690 for Nikon i-TTL auto zoom head

The two main modes for this flash is TTL mode and M mode:

a), TTL mode,the metering system of this camera will detect flash illumination reflected back from the object so as to automatically control flash output in this mode. When taking photos, you only require aiming at some scene and press the shutter after focusing, the light will give proper light as per tips and then you can get your desired photo. ( This mode can only be used in compatible Nikon i-TTL mode)

b), M mode,you can set flash luminance as per your favorite, luminance level will be displayed by luminance indicator. When taking photos, you only require setting the flash luminance, adjust the camera and press the shutter, the flash light will flash under the camera synchronous signal.