Is there a delay in the a7r3 viewfinder?

Generally speaking, there is no such thing.

On the sensor of the camera core, A7R3 uses an image sensor with about 42.4 million effective pixels, with 399 phase detection autofocus points, compared with 425 detection autofocus points; ISO is100-32000; A7r3 fuselage has anti-shake system, r3 can compensate the shutter speed of about 5.5 at most. R3 also has pixel conversion multi-beat mode.

Camera evaluation:

In terms of video, the autofocus character moved backward, and it felt a little backward at first. Another thing is that its screen is really not very good. Although the screen of Sony A7r3 has been greatly improved compared with A7r2, compared with Canon's magic screen, there is still this (not too big or too small) gap in the skin color of the characters. Watch this electronic screen when shooting video, especially when there is enough light outside.