Had the doorbells and external camera for varying lengths but had no issues with clarity during the day or night. However after a weekend away and checking the cameras remotely (as you do) I noticed that I was getting an odd blur so I couldn’t really see what was going on, just a smudge of a picture. The following morning it seemed ok. It did the same the following night, I suspected that maybe a spider had made its web over the lens and was catching reflections at night (oddly on two different things in different places). When we got home I used a big duster on a stick to clean the camera and the door bells etc. Seemed ok that night,but it wasn’t as cold that night as it had been. A few nights later it did it again in the middle of the night (looking back at triggers) , cleaned again but it still did it the following night.

Is it the lens losing focus and focusing on the glass ? Are they letting water in and its condensation? It never actually looks like its got a web over it, I should point out.

Thanks