Sony F43 vs F58 Flash

Well, I use both an F43 and an F58. The F43 is my general travel flash being a little smaller and lighter. I use the F58 when I anticipate the need for more power--i.e., longer distances, larger rooms, darker or higher ceilings, larger groups, etc. Combining the two with wireless flash makes for a quick and dirty two-flash system. The F43's weather-sealing has never been a significant factor for my shooting.

I must say that I cannot ever recall running out of power with the F43. In part, that's probably because I anticipate when a more powerful flash might be needed. But it's also a function of what apertures and ISO settings one uses. For indoor flash, I generally shoot at f/4-f/5.6 and at ISO 400 (or sometimes ISO 800 for longer distances or darker rooms).  This is for general shooting, of course.  Portraits are another matter, and I use a Sigma ring flash for macro work.

I can only recall my F58 overheating once. Like Bill, I use an 8-battery flash pack for faster recycling when I expect to be taking a lot of shots in rapid succession. Note that the F58 has a terminal for connecting a battery pack, while the F43 does not. So that's a possible reason for choosing the F58 over the F43.

With regard to diffusers, there are many to choose from with more being introduced every month. As Bill has pointed out, they will soften the light and reduce shadows (within a certain distance range), but they also reduce flash power anywhere from a stop to more than 3 stops, depending on the particular diffuser. I use the Lumiquest Pro-Max System and also a Lumiquest Softbox, depending on the situation. The Pro-Max System has inserts to use with high or dark ceilings.

For reviews and ratings of various flash diffusers, see:

http://photo-tips-online.com/review/best-flash-diffuser/