Took the M2 out for a spin today, and noticed a bit of a problem…
(…Do you see it?)
You can compensate for it by cropping, or using an artificial grad filter in post:
And it doesn’t seem to occur at all speeds.
Here’s one at 1/60, that didn’t exhibit the problem:
(The others were all shot at 1/1000 or 1/500s…)
In any case, the shutter timing is off.
Here’s what it looks like unedited, at 1/1000s:
Anyway, the second curtain is too fast, the shutter is too tense, or the whole thing just needs a cleaning and lube.
So, unfortunately, a CLA is exactly what it will get.