A reflector is helpful with those T8 bulbs but it looks like he can get pretty close to the fixture. How far is the top of that log from the bulb? If he can get to about 6'' away it should be OK.
He's definitely that close. He usually sits up on the log or where he is in the picture where his basking lamp is. I just wouldn't know how to go about reflecting the light
Turn it flat facing straight down with the ballast compartment facing the outside towards you, this will make it more efficient and, not hurt your eyes as well.