I have a Fuji X-T10 and an XC 50-230 4.5-6.7 OIS II lens. Normally its OIS is incredible. But there is a particular combination of settings that is giving me trouble. I would like to know if this is normal behavior or if I have a goofy copy of the lens.
The below picture is taken at 230mm, f/6.7, ISO 3200, 1/40s, continuous OIS, and electronic shutter:
And this is taken with the same settings but with mechanical shutter:
There is an issue with the mechanical shot: there is an artifact that looks like completely horizontal hand-holding wobble. The LED is a particularly good spot to check because it is bright, but the entire image appears this way. The wobble is always completely horizontal in the image, even if I hold the camera at a 45° angle.
UPDATE: here are a couple images taken on a tripod, mechanical shutter, 1/30s, OIS on. They are resized, but this is the full frame; this is not a 100% crop.
This problem is most apparent between mechanical shutter speeds between about 1/20–1/100 or so. Sometimes it is a complete non-issue, and sometimes it is very glaring—the amount of wobble changes per-shot.
Disabling OIS causes the problem to go away (leaving me with normal handhold wobble). Switching to electronic shutter makes it go away too. Changing to a faster shutter speed makes it go away. I do not have this problem with my XF 18-55 lens.
The only thing I can conclude is that the shutter is jarring the OIS mechanism enough that it loses its lock. I have heard this called "shutter shock," but never to describe interference with OIS, just in conjunction with long exposures. But I don't know if this is the correct explanation. And I don't know if it's a limitation of the lens or if my copy is the only one exhibiting this behavior.
What causes this artifacting? Can anyone else reproduce this? Or is this a commonly-known behavior of OIS tele lenses? Unfortunately my camera does not have electronic-first-curtain; that would be a pretty good workaround if my diagnosis is correct.