Sony’s unique speedlight design requires a different approach when it comes to flash diffusers and bouncing. To that end, Gary Fong has developed the Gamma Diffuser for the Sony HVL-F58AM and HVL-F43AM speedlights.
There’s a brief intro in the following video if you can get past the rather poor audio, the design makes sense in terms of its functionality and performance.
[youtube http://www.youtube.com/watch?v=n8QM90qGLAY&w=640&h=360]It’s currently available for $30 from Adorama and Gary Fong’s website.
There’s no such thing as “Sony Alpha Speedlights”.
Speedlight is a name Nikon uses for it’s flashes. It doesn’t have anything to deal with Sony, as same as Sony doesn’t have DX cameras – they have APS-C cameras (DX is another made-up Nikon name)