I added one more GX lens to the lineup: the GX 125mm f/5.6.
The "kit" lens for this system was the GX 135/5.6, which has the same angle of view on 6x8 film as a 77mm lens on a 33mm x 44mm sensor if we're comparing the long edge. That means the GX 125mm f/5.6 has an angle of view on 6x8 film comparable to a 71mm lens on a 33mm x 44mm sensor (so still not quite a "normal" lens for the GX system).
I chose the 125mm because it falls better between my APO-CPN 90/4.5, and my Mamiya G 150mm f/4.5, and gives me two times normal. Also, I was taking a chance that it was a symmetrical design, which proved to be the case.
I haven't had the lens nearly long enough to offer anything conclusive in the way of a review. However, I had a chance today to put it through its paces and can already say it's a delightful lens that I'm glad I purchased. If you're looking for something in this focal length, it's worth considering if you can deal with the register distance.
I don't have a GFX 120mm lens to compare it to, but I have had three other 120mm lenses over the years in my quest for twice normal. I'm mildly obsessive about evaluating new lenses, and I keep all the results even if I don't keep the lens. Thus, I'm able to say how it does against three other really good 120mm lenses that I didn't keep for various reasons: SMC Pentax-A 645 120mm f/4 macro; Rodenstock Rodagon-WA 120mm f/5.6; and Schneider-Kreuznach Makro-Symmar HM 120mm f/5.9. All three were excellent lenses, but with some qualities that didn't make them keepers. So far the Fujinon GX 120mm f/5.6 is doing very well in comparison, even against the superlative (at its design distance of < 2m) Makro-Symmar 120/5.6. The best aperture of the GX 125/5.6 seems to be f/8, but wide open is completely usable, as is f/16.
The Fujinon GX 125/5.6 is nearly symmetrical; I calculated a flange distance of 127.5mm. This makes it ideal for axis tilt because the need for recomposition when tilting is minimum. In comparison, the strong retrofocus deisgn of the GX 65/5.6 and the telephoto design of the GX 210/5.6 and 250/5.6 lenses do not play well with tilt; it works, but if you've ever used a true telephoto lens on a large format view camera, you know what I mean. When using axis tilt with the GX 125/5.6, the image barely moves as you tilt.
Image quality is definitely a bit better at f/8, but f/16 brought the tops of the tools into focus (with the exception of the very tip of the spanner).
Another nice feature of the GX 125/5.6 is it's extremely light. The two lens cells together weigh 180 gram. In comparison to its enormous sibling, the GX 65/5.6, the GX 125/5.6 is a feather weight. The GX 125/5.6 shares the 82mm front filter thread of many of the other GX lenses, but Fuji made this decision simply as a convenience for photographers, and not because of the size of the front element. The actual lens front element is recessed so far into the housing that the housing acts as a built-in lens hood.
With its enormous 120mm circle of good definition, and an absence of noticeable light falloff until very large shifts, this is a lens where I'm going to be able to use movements without having to constantly watch out for the edge of the image circle.
I haven't noticed any serious optical flaws yet. Distortion is as close to zero as I've seen in a lens that weren't designed for repro. I tried to produce some chromatic aberration and haven't seen any yet, even wide open; it's premature to say it doesn't have any issues because I haven't used it enough yet, but given what I tried so far, the signs are good.
One thing I noticed today is that the lens has a very pleasing, gentle transition from in-focus to out-of-focus. Here's a scene from a walkabout with the lens today. Below this picture is a 100% enlargement to show how the lens handles the transition to out of focus.
The focus was on the snow on that angled tree trunk in front, and it's nice and sharp. I wanted the trees in the background to gradually blur; the lens delivered.
All in all, I'm very pleased with this especially considering how inexpensive it was. Once I build a housing for it, it's going to be a mainstay in my outfit.