Have never used flash with 4x5, but about to. The Vivitar 285 I use with 35mm h as zoom capability...makes sure the flash is "wide" enough at 35mm focal length, and doesn't waste power at telephoto. I assume the calibration for these flash es is all 35mm "normal" when they say 50mm. Said another way, since if I'm at t he same place with 35 and 4x5, and use 50mm and 150mm lenses respectively, I'm g oing to need to cover the same scene with flash, I assume I'd use the normal fla sh setting for both. Right?