anyone use an opteka flash???

hi, i have a d3100 & d5000 and want to use an opteka flash ef710dg-n which is supposed to be a i/e/super ttl flash???(dependent on which web site you look under)anyway after my last post about flashes i am now trying to figure out how to change the power/speed of my flash however there is no lcd on the flash so i assume that it is done through the camera????or is it only selected by the camera and not user adjustable????

I cannot find a description of that flash on the Opteka site, and the Amazon site is a bit sketchy. But my opinion is that it does not do manual flash mode. It has no menu to set manual flash power. It is a TTL Only flash, and the camera sets flash power according to how it meters it. This is sometimes the case for inexpensive models.

The way you adjust your TTL picture exposure result is with flash compensation on the camera. If the picture is too dark, you add a bit of + EV flash compensation. If too bright, you add a bit of - EV flash compensation. As you see is needed.