This is the thirteenth in a series of posts on the Fujifilm GFX-50S. The series starts here.
In the last two a7RII/GFX tests, we found that the 120mm Fuji macro is a pretty special lens, and that the 63mm Fuji normal lens is no slouch either. It wasn’t much of a contest with the Zony 55 and the Sony macro — both good lenses — on the a7RII. What if we pull out all the stops and mount the Zeiss Otus 85mm 1/1.4 on the a7RII, and leave the 120 macro on the GFX. In one sense, that sounds like we’re being unfair to the GFX. But in terms of dollars, the Fuji GFX and the 120 macro cost more that the a7RII and the Otus.
Here’s the setup.
Shutter set to EFCS for both cameras, which meant it really was EFCS for all the pictures with the Sony, and was EFCS at the narrower apertures for the GFX. Exposure compensation set to zero. AF-S used for the Fuji, and manual focusing for the Otus. I focused five times at each aperture with the Otus, and picked the sharpest images. 2-second self-timer used in both cases. Arca-Swiss C1 cube on RRS sticks. The Fuji images were about 1/3 of a stop darker than the Sony ones at the same exposures. I don’t think this is due to lens transmission; I think it’s actually the result of the way that Fuji set up the GFX. I think that, set up the same way the a7RII is, the GFX base ISO would be 80. Focus was in the center of the image, and all images were refocused at each aperture. Tripod and head were not moved between series.
I developed all the images in Lightroom with default settings, including exposure. For some reason, this time the brightnesses were very close. I dispensed with Iridient X=Transformer, since it seems to be the case that Lightroom’s default sharpening isn’t tilting the playing field.
The overall scene with both setups:
In the center, at roughly 250% magnification for the GFX, and the same vertical sensor extent for the lower-resolution a7RII. This would give the same vertical field of view if the lenses were vertically equivalent focal lengths. Details: the GFX crops are 357×277 pixels, and the Sony crops are 306×237 pixels. All are enlarged to 700 pixels high on export from Lightroom.
It looks like resolution is mostly limited by the sensors, and the sensor resolutions in pixels aren’t that far apart, so the images look very similar.
Near the left-center edge:
The Otus has a little difficulty at f/2.8, but is good at f/4.
Pretty much a wash.
Now that diffraction is starting to dominate, the GFX, with its bigger sensor, looks better.
With even more diffraction, the differences are greater. Feel free to compare the 120 macro images with the Otus ones that are made a stop wider; that will equalize diffraction.
In the upper right corner:
The Fuji lens is very slightly softer.
GFX maybe a little softer.
Now we’re diffraction-limited, and thus the Fuji looks better.