Its not dust, its ir reflection. See the videos of the hik doorbell, all the same. This is a design defect.
So no point in asking for an exchange. Refund or live with it - which is not the way to conduct a business. It would be easier to live with if it wasn't such a half-baked product. At my "villa" level of use, the only things it does well are open/close my gates and facilitate reasonable quality audio. It's staggering that there's no way to record visitor footage to an SD card - which according to Hikvision tech support is exclusively for the recording of voice messages and storage of a single snapshot per visitor [which is such low quality that it's impossible to identify my own mother].
As for limiting the live view time on their panels to a maximum of 60 seconds, were these devices originally planned to be battery powered? The logic escapes me - especially when the graphical home screen stays live for 5 minutes before it goes to sleep.
And I absolutely hate the constantly shifting pixels, even in good, stable light. Why is that happening?
I found out in
another thread that iVMS-4200 version 3.2.0.10 lets you turn off the
IR light so I'll see what happens tonight.