it's just rolling shutter on a slow-reading sensor
Photography
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I wondered about that, but wouldn't their legs be in odd positions or bent?
My first thought is rolling shutter, based on the angle. That's the sensor refresh read pattern.
A7RIV has one of the slowest reading sensors in the business. Electronic shutter will be very prone to rolling shutter distortions of anything moving during the shot. Even camera shake.
Basically takes 1/15th of a second to read the full sensor top to bottom.
Wow, that graph, the canon R is even worse. What are canon playing at with R? The lenses (what few there are) are dogshit and slow,... is the whole R project just a huge mistake? Canon seem to have really dropped the ball.
Did you look at the fastest reading non-stacked sensors? R6, R5, and R6II.
R was a toe dip into Mirrorless recycling an old DSLR sensor.
I'm assuming this isn't a cropped image.. You have vignetting in the top right corner and not in the others.. I'd say that you have a lens element that has decentred. A job for the service/repair people I think