ADI - TTL (a350 user)

[jong]

just got a HVL-F42AM for my a350 ( sony len) and been trying to use ADI & TTL to meter but all i see is a blinking arrow to the left which means under expose or to dark and even with the pre flash TTL, the flash won't even do a pre flash to meter off ? I am confuse, Am i doing something wrong ( me newbie )? do i need to buy a light meter to get a correct exposure/ cause now, when using my flash, i use the trial & error method and just check the histogram get the desired exposure. thanks