Minolta Booster II for the truly anal Zone System LF photographer. With this puppy you can measure the exposure right on your ground glass. Take as many readings as you want from the comfort afforded by your dark cloth. $80USD + $20USD shipping. Canada and US only.
Shooting 4X5 chromes with studio lighting can sometimes be tough without Polaroid 58. This is especially true if view camera movements are properly used for table top product/food shots. Bracketing doesn't deal with shadows Vs highlights as well as does lighting adjustment, and can be expensive. Been there, done that.
i'd for sure want Eric's gizmo if I was still in that business. It'd be a bargain.