Greetings, Can someone with an F5, and SB28 speedlight explain how to best use these with an old Vivitar non-TTL (manual) flash as a second light? Will the F5, SB28 combination automatically handle (via TTL) the Vivitar's extra light input or will I be forced to manually compute settings for the Vivitar? I realize I'll need a sync cord from the SB28 to the Vivitar. Thanks, Jeff Kelley [EMAIL PROTECTED]