Lewis Von John put together a tutorial about how to calibrate your light meter specifically for the Fujifilm GFX 50S, to get the shot right the first time. He uses a Sekonic l-758DR light meter and X-Rite ColorChecker to create a profile for his meter, which consists of 3 shots (one normal, one 3 stops under exposed, and one 3 stops over exposed). If you want to shoot landscape with your GFX, owning a light meter like the Sekonic will definitely save you time if you are doing long exposures.
Fujifilm GFX 50S B&H Photo / Amazon / Adorama
Sekonic l-758DR B&H Photo / Amazon / Adorama
X-Rite ColorChecker B&H Photo / Amazon / Adorama
