…Hummingbirds or any other fast moving subjects.
Why? The great advantage of mirrorless interchangeable lens cameras is they can be completely silent whilst in electronic shutter mode – an invaluable feature if you’re photographing a wedding ceremony, or shooting skittish wildlife, but the rolling shutter phenomenon is something that can render an image unusable if you’re not careful.
When the electronic shutter is enabled, the image is not captured all at once, but by rapidly scanning the sensor vertically or horizontally. This causes distortions in the image where otherwise straight lines can be skewed, or moving object such as a bird’s wings or propeller blades can be facing unnatural directions or be completely deformed. This effect is most noticeable when cameras are in electronic shutter mode, when the mechanical shutter is disabled, but can still be visible with some cameras with the mechanical shutter engaged. The examples below were shot with a Nikon Z7 with a Nikon 300mm f2.8VR + Nikon 1.4x Teleconverter III attached. The camera did a fine job tracking the hummingbird in flight, but as I had the electronic shutter enabled, it did some strange things with the wings.