First off, thank you to all the people that sent me emails with advice and questions about my notion that OIS on the 18-55mm XF might actually be causing issues. I really appreciate it. I made a very general proposition and cast a fairly wide net without all the details — my bad. Here's some possibly relevant details and clarifications.
First off I want to unequivocally say that I cannot reproduce my suspicions on demand. If I could I would have my answers. The above photo is typical of my 18-55mm XF shot at high-ish shutter speeds when forgetting to turn the OIS off. Specs: 35mm 1/180th f/4. What's more it's a one-hander with me not in the most stable picture-making stance with a ton of stuff going on. In these circumstances if anything were "off" I would have a hard time evaluating why with me being the prime culprit.
Yes, I am using mode 2 set in-body. Found that little tid bit out when I came to the conclusion the 18-55 OIS sucked. Fuji should relabel these as "suck" and "don't suck". Anyone found a use/circumstance for "suck", aka mode 1?
Above are my typical results. Typical has different interpretations to different people so let's quantify that. Somewhere along the lines of shooting for 4 or 5 days on/off, maybe 1000 frames with no issue. Hundreds of those forgetting to turn the OIS off at 1/180th or higher. I don't make crap tons of pictures in one sitting or even on one subject or project but I do make crap-tons of stuff across everything I do. I am at more than 30,000 frames having had the XT-1 one year and one month.
My experience with the Nikon 70-200mm f/2.8 VR and what happens very consistently (like every frame) if you leave VR on and tripod mount it are what is causing my suspicion. With that lens it's easy to reproduce. The fuji has a similar "look" of sort of out of focus but not near that consistently even if you tripod mount it and leave OIS on.
I notice it here and there as in a few frames within the same shooting session where the images should be pristine. Example shooting with strobes that have at least 1/1000th flash duration, no ambient contribution to exposure, f/8, 1/180th and enough depth in frame to assure myself it's not a focus issue. In other words i'll see something wrong with a few frames out of that same session with no explanation of why but won't see it again for a month or so and even then infrequently.
So with all that you may be asking so what? Consider it one of those things that just nag at me without any real world impact. An academic curiosity more than anything else. It's also reason enough to remind myself about it so that I actually remember to turn it off when I absolutely don't need it.
Errata & Misc Housekeeping
While we are on the subject of emails, clarifications, and questions I'll move on to the 18-55mm XF vs the 35mm f/2 WR. I received quite a few questions and disagreements with some of my assertions and thoughts on the 35mm f/2 in my admittedly cursory non-review of that lens.
The random images I included here are decent examples of my conclusion that most people will not notice a night/day difference between the 18-55mm at 35mm and the 35mm f/2 WR. If like me you don't shoot the vast majority of your pictures at exactly optimal conditions you'll never see the difference on any consistent basis. Can you tell between these and the few I posted in my quick assessment? I can't. Even if I look at them under a microscope (pixel peep) and get rid of all the fake grain and things I can't.
Does this mean some how I am looking at sub-par images? Not in the least, in both cases with both lenses pixel peeping 16 megapixels of the XT-1 reveal no significant technical flaws in terms of sharpness, definition, or contrast. What's more is the 18-55mm renders in a pleasing way as well. Something that is not the case with a lot of zooms, even high-end zooms. It means when I look at images that I consider technically good or great with those parameters considered even the less quantifiable ones such as focus transition and "look" don't drive me towards choosing the prime.
Will all that change when I can look through a more powerful microscope with 24 mpix sooner or later? I don't know, maybe but I doubt it.
On the other hand take the above image. Notice anything "wrong"? Check out the lack of overall contrast especially as you move up to the upper left hand corner or anything near that. That's the flare I referred to, that kind of overall veiling hazy kind of flare. The kind you usually don't want. This kind of thing is easy to provoke with the 18-55 XF when not using a hood which I never use a hood, makes that lens too too big. The 35mm f/2 WR almost never does this even if you try. This happens on the 18-55 with anything resembling a similar brightness to your main subject light when it falls at 90 degrees to the front element or thereabouts.
All photos made with the Fuji XT-1 and 18-55mm XF. Processing via Lightroom CC with VSCO FILM 05 BW400CN applied on import.