My IR testing of my full spectrum GFX50S with the Fuji 45-100mm Zoom shows that 680nm and 720nm filters are usable for all apertures up to f/16 over the entire Zoom Range. The 760nm filter is usable for all apertures up to f/16 over a zoom range of 45 to 80mm but there is a mild center hot spot at the 100mm setting. Unfortunately neither the 850nm or 950nm filters are usable due to medium - severe hot spots at all apertures over the entire zoom range.
I have found that the 32-64mm zoom is unusable at 32mm for all filters except the 680nm and 720nm up to f/8; at 45mm it is usable for the 680nm and 720nm filters up to f/11 and at 64mm the 680nm and 720nm filters are usable to at least f/16 and up to f/11 for the 850nm filter but unusable for the 950nm filter for the entire range..
In contrast to the mixed IR behavior of the other zoom lenses, the 100- 200mm zoom is usable for all of the filters at apertures up to f/16 over the entire zoom range which makes it a great lens for IR Photography as is the 45mm f/2.8 Prime.
I have found that the 32-64mm zoom is unusable at 32mm for all filters except the 680nm and 720nm up to f/8; at 45mm it is usable for the 680nm and 720nm filters up to f/11 and at 64mm the 680nm and 720nm filters are usable to at least f/16 and up to f/11 for the 850nm filter but unusable for the 950nm filter for the entire range..
In contrast to the mixed IR behavior of the other zoom lenses, the 100- 200mm zoom is usable for all of the filters at apertures up to f/16 over the entire zoom range which makes it a great lens for IR Photography as is the 45mm f/2.8 Prime.