Is there a through explanation of the flash modes anywhere? The only one I really understand is NO FLASH. Works as expected. TTL isn't listed anywhere and, with my 3rd party, so called compatible flashes, AUTO isn't available and FLASH w/o "fillin" is a blowout every time. Why? For starters, I'd like to master fill flash. I know the basics; they got me through several years of weddings with a potato masher on my Mamiya Press, but everything eludes me now. I shot a dog show today: bright, overhead sun around noon, clear skies, etc.... the shadows are deadly. Help!