This is the 74th in a series of posts on the Fujifilm GFX-50S. The series starts here.
When I was testing the GFX 50S, I did a lot of work with adapted lenses. I’ve received information about many lenses that I did not test from a reader named Robert Jones. I think it’s sufficiently interesting to post here.
Take it away, Robert:
I wanted to mention a really nice, manual focus telephoto that I think is under the radar for many people. The lens is a Kowa Prominar. The Kowa comes in several mounts, but I think the Nikon mount version makes the most sense as it can be used on many brands with a simple adapter added between the lens and the camera. I got the lens off eBay from a Japanese dealer. There is a main head unit, which contains 1 fluorite along with 2 extra-low dispersion elements, and a round 9-bladed diaphragm. Between this unit and the camera are 1 of 3 possible tubes (“mount adapters” per Kowa), used one at a time, which create a 350/4, a 500/5.6 or a 850/9.6 telephoto lens. I got the 350 and 500 units. There is no glass in the 500mm tube, but the 350mm tube has several elements (I think the 350mm tube is behaving like a Speed-Booster).
Since the lens breaks into 2 (or 3 or 4 pieces) it fits smaller camera bags unlike most 500mm lenses. And the weight is rather light at 2 kg. Kowa also makes a special fluorine-coated protective filter (95mm) for the main unit. While the focus is manual, it’s very smooth, having both coarse and fine focusing rings. Close focus is 3 m. Using the EVF on the NX-1 together with MF assist makes using the lens easy (easier than using LV on my D810 in bright light; surprisingly, the NX-1 seems to have better resolution that the D810 with this lens).
This lens works amazing well on the GFX. It is sharp across the whole field. Only the extreme corners benefit by stopping down 1 to 2 stops. With the 2 adapters I flexibly have a 350mm (f/4) and a 500mm (f/5.6). I’ve tested it against the latest Nikkor 400/2.8 FE on a D810 (both a rented unit and a personally purchased unit) and the Kowa was easily superior (I sold the 400/2.8 FE). The Kowa is manual focus but MF is easily done on the GFX. I especially like it at 350mm. For most subjects wide open to 1-stop down is great.
I also tested the following lenses on the GFX:
1. Leica 180/2.8 APO. It is perfect. (I’m selling the Mamiya 200/2.8 APO which is a cheap imitation of the Leica APO). The Leica 180/2.8 APO at f2.8 is simply remarkable; no need to stop down. Easily as sharp as the Fuji 120/4 macro.
2. Nikkor 24, 45 and 85 PCE lenses. All work well (unshifted), but the 85 PCE is the best, esp as another macro lens. Wide open it is excellent with no fall-off. The 24 and 45 are only usable wide open unless set up with a second body.
3. Nikkor 58/1.4-G (latest version). Very nice, using a G-adapter. (I have the 85/1.8-G, but did not test.)
4. Nikkor 20/1.8-G. A surprise. With the G-adapter (maybe about f5.6?), it has excellent sharpness and contrast in the margins. (I do not have the Fuji 23mm to compare; I would imagine that the Fuji is better.) I will happily use it as a 16mm equivalent.
5. Nikkor 70-200/4 (latest version). Lousy.
6. Pentax 67 55/4 and 200/4. The 55/4 (latest version) is an incredible lens, esp around f5.6 to f8. It focuses very close and can function quite nicely as a macro lens. I’ve used this lens on the Pentax 645D and found no equal at this focal length. The 55/4 is easily travels in the prime Fuji lens territory. The 200/4 simply pales in comparison to the above Leica or the Mamiya 200/2.8 APO; it’s a no go.
7. Pentax 645 lenses. I’ve only tried the 75/2.8. Mediocre at best. Since the Leica 180/2.8 APO is so good, I see no reason to deal with the 150 or 200 Pentax. Since the Kowa 350/500 is so good, I see no reason to deal with any longer Pentax 645 lenses.
8. Pending on arrival of AF converter: Contax 55/3.5, 80/2.0, 140/2.8 and 210/4. (I still own these from my Contax 645 days.)
9. Pending on arrival of AF converter: EF lenses such as the 17 and 24 shifts, 100 macro. But with the 120 Fuji macro, why bother with the latter?
I own a CO 60mm APO. The Leica 180/2.8 APO, the Pentax 55/4, and the KOWA 350/500mm are in the same league. I think the new Fuji 120/4 runs in the same circles.