In Depth Study: How Shutter Speed and Aperture Mangle Bokeh with Electronic First Curtain Shutter (vs electronic shutter and mechanical shutter)
I was vaguely aware of bokeh differences with fast lenses at high shutter speeds, but since I usually shoot the sweet light whenever I can, it was never much of an issue.
The use of electronic first curtain shutter can mangle lens bokeh at very high shutter speeds—even stopped-down to f/4 (with some effects even at f/5.6). The article suggests various mitigations.
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In Making Sharp Images, I show how shutter speed and aperture mangle bokeh with electronic first curtain shutter versus electronic shutter and mechanical shutter. These findings will apply to all lenses of any brand on modern digital cameras with only slight variation.
This page takes a thorough look how bokeh changes depending on aperture, shutter speed, and type of shutter:
Making Sharp Images: Effect of Shutter Type on Bokeh vs Shutter Speed and Aperture
Includes 48 frames at up to full camera resolution from f/1.4 to f4 at 1/8000, 1/4000, 1/2000, 1/1000 shutter speeds using mechanical shutter, electronic shutter, electronic first curtain shutter.
Also added:
Striping from Electronic Shutter with Artificial Light