@joseph_1979 Thanks again. I found another, very cheap solution: I borrowed a few different old reading glasses from my old neighbour. With 3.0 diopter it worked perfectly. So I odered exactly round glasses in a size which will cover the complete front of my RLC-110A. Four small drops of black silicone and the job will be done.

@joseph_1979 Thanks for your info. I know the specs but they don't help in this case because the focal lenght doesn't tell anything about the real focus distance. For example I have the RLC-810A and the RLC-820A. Both have a fix focus lens with a focal lenght of 4 mm and their real focus distance start around 30-40 cm, which is to far away for a birdhouse inside view. I also have the E1 Outdoor PTZ which has a varifocal lens with focal lenght between 2,8 and 8 mm and its real focus distance is unter 10 cm which would work fine (it is impossible to mount this PTZ cam partly in a birdhouse). The specs of the E1 are very similar to the RLC-811A so I think its real focal distance is very short, too, but I woud like to know it for sure before ordering it.

Hey dear comminuty,

I've installed an RLC-810A camera on a birdhouse and noticed that its fixed-focus lens produces blurry images at that short range. Now I'm considering purchasing the RLC-811A model instead, because it has a more enhanced lens system. Does anybody know what the minimum object distance required for the RLC-811A is to achieve focus?

Best regards,
Kanso