In this test I will be looking at some of the fundamental differences between the Fuji 120mm F4 macro vs the Sony 90mm F2.8 macro. These two lenses are each manufacturers macro offerings of around the same field of view so make for a great comparison especially since these are two lenses I use on a daily basis.
Size and Weight. From the opening image there is a noticeable difference in size, especially considering the larger of the two is actually a slower lens. The Fuji 120mm has a minimum f-stop of F4 while the Sony 90mm is one stop brighter at F2.8. There is a 50% weight gain with the Fuji coming in at 980gm vs the brighter Sony 602gm. As a high megapixel image creator, I use these lenses the most often to create my Gigapixel stitched images. They provide great detail as this technique requires multiple images to be combined to create one gigapixel image. So this is where things get interesting. To ensure perfect alignment in stitching the lens must be placed at its nodal point to ensure no parallax errors occur. The Sony 90mm macro has a good positioned nodal point midway down the lens. However the Fuji nodal point is located much further down the lens which makes my pano rig quite a bit out of balance. I have contacted Fuji to see if I can loan a 110mm f2 which is a close focal length alternative. I haven't given up on the 120mm macro as there are work arounds to compensate but that comparison will be interesting.
Sharpness and AF Speed. The focusing speed on the Fuji 120mm was surprisingly faster than I expected. I had read reviews that labelled it 'slow', however in comparison to the Sony 90mm it is at least if not better. The Sony 90mm is a quite slow focusing lens overall and has never worked well for me with portraits, so I assumed the Fuji would be too but that was a happy surprise that I think it might be up to the task. I will be interested in comparing this with the Fuji 100mm F2 when it arrives.
In relation to sharpness that was a hard one to seperate. Both lenses perfom exceptionally. I would not hesitate to use either for high detail work or for landscapes. The following are some comparisons between the Sony and the Fuji.
Again you can see the resolution difference between the images and the increased detail that comes from the 102mp second on the Fuji GFX 100s. Between these two lenses factoring the resolution difference etc, I would draw it a tie for sharpness and AF speed. I will draw my final conclusions once I get a chance to get my hands of the Fuji 110mm as to whether I will use the 120mm or 110mm in the Fuji lineup.