better beamer & canon 580EX how to

Good Afternoon, as a new member; i'm hopefully someone could point me in the right direction here.
My equipment is canon 50d, 500mm F4 IS, canon 580 speedlite, and better beamer. I read the lumious landscape , telling me all the reasons to use the netter beamer but, i have no idea where to go from there.
Seem's that my reading shows i should set the flash for:
50mm zoom
then underpower setting, like minus 1, or so
Do i use M, or ETTL setting on the flash, i'm learning to shoot in the manual mode on my camera.... however i'm thinking that as the light wanes for the day, maybe AV is better, or does one just constant chang the nabual settings as the light dims.
Just trying to get out and play some this pm, but do not have a clue where to start.
Any help would be greatly appreciated to do some fill light on some great egrets, and stuff...
Don

Don,

Here is an article that I wrote a couple years ago on the subject that should answer your questions:

http://www.naturescapes.net/docs/index. ... h-x-tender

Wow, awesome, Thks so much!!! Man, a most impressive timely response!
Thks
Don

Greg, i just read , certainlyy hepful article indeed. So i'm
going to set the flash for the ttl mode, and zoom for 50mm and then look at the measuremnet scale that the flash LCD shows, which reveals the effective flash distance. Then figure out the -1 0r -2 settings... is this is correct.
Don

Hi Don,

From my experience I start with -2 (stops) Flash compensation when using the beamer and adjust accordingly based on the histogram to enusre I'm not blowing highlights.

Greg Downing wrote:Don,

Here is an article that I wrote a couple years ago on the subject that should answer your questions:

http://www.naturescapes.net/docs/index. ... h-x-tender

Thanks for sharing, Greg!!!

The settings of -2 having nothing to do with the better beamer - just as an FYI - that is where you typically would start with ETTL fill flash with or without the better beamer. Since the flash is reading the reflective light bouncing off the subject and adjusting the exposure based on that then the better beamer does not affect your actual settings. In other words pretend it is not there and the flash will do the work when in ETTL mode. The only time it will need additional compensation is when shooing manually. You also want to remove it if too close to get a proper exposure (based on the near distance indicator.)