This is the 46th in a series of posts on the Fujifilm GFX-50S. The series starts here.
I’ve been asked to run the same focus shift and longitudinal chromatic aberration (LoCA) tests that I did at 1 meter on the Fuji 120 mm f/4 macro lens for the Fujifilm GFX 50S, but at a closer subject distance. I went as close as the lens will focus, to a reproduction ratio of 1:2.
You can read up on the test protocol here.
Looking at the LoCA at f/4 through f/11:
At f/4, the 120 macro is not as sharp as it is at 1 meter, especially in the blue channel, and has more LoCA.
This is also not as good at at 1 meter, but is quite respectable.
Pretty close to the same as f/5.6.
Again, not quite up to the performance at 1 meter.
And now the focus shift in the green channel:
The focus shift looks to me to be a bit worse than at 1 meter as well. I’d foucs at f/4 for f/4, f/5.6 for f/5.6, and f/8 for both f/8 and f/11, and probably all narrower stops.
It looks like Fuji designed this lens to be at its best in other than it’s nearest focsuing distance. I think that’s the right decision, at least for the way that i intend to use the lens.