Video door intercom system - Which one is recommended?

You still need a notice at the entrances to the yard/property. So that everyone knows that camera surveillance is taking place. Even now, since you write that you already have cameras in operation.

In principle, any outdoor pinhole camera would work. You need wide-angle or fisheye. In the worst case, a mounted dome camera would also work. But better use a pinhole. It looks much better.

A camera integrated into the doorbell system is nothing special either. On the contrary. Usually outdated technology that is sold at an extremely high price. Which camera you want to use depends on the budget. €100 is too little. Take a look at the AXIS P1224-E. The resolution is sufficient for the doorbell.

How do you want to record or retrieve the stream? Or what kind of camera system do you have in the house? Any licenses left... I get the impression that you are not very deep into the subject. So please provide the information briefly. Not that you have a proprietary system and cannot integrate any standard cameras.

Yes, the labeling is already done – we have been monitoring our property for quite some time.

Theoretically, there are already 1080p webcams available today that you can get for €60, right? But I need a camera that can be connected to the network via an Ethernet cable and then accessed via an IP address. Currently, we access our cameras through an (old) tablet that is constantly mounted on the wall (via an app that is practically always open. That was free since the tablet was already spare and it works perfectly).

Our camera center (Ctronics Wireless Surveillance Camera Set including 1080P - 4 cameras, waterproof with night vision - indoor and outdoor) combines the 4 cameras and displays them clearly for us, e.g., on a TV device.

We have Fritz Fons in the house (AVM FRITZ!Fon MT-F) – the "ringing and then we get a camera image" won’t work with them. So it’s enough if we use a normal IP cam in our network.

I have never really delved deeply into it – even though we have over 50 IP devices in the house, 4 Fritzboxes, etc... (multigenerational house).

PS: Am I right that the AXIS P1224-E costs over €400? That’s more than I paid for the 4 Full HD surveillance cameras.

But FritzFon can show an image when ringing provides good instructions for this.
There are also alternatives with lower resolution that are cheaper, like the suggested Axis. If optics are not that important, you can get by with a dome camera for about €250.
Good cameras cost money (night vision, heating, motion detection...) so you’re quickly between €500-1000.
If yours are sufficient for you, that’s great.
Whether you can integrate additional cameras into your existing system I have to check.
But through an app on the tablet, it always works. Just no recording.

Does the camera image on the Fritzfon have to have a certain resolution? I seem to vaguely remember that... Dome camera for 250€? Hmm, that's still quite expensive. I find when I look for IP cameras starting at 20€. If I put a piece of plexiglass in front of it, that should work too, right? Or I just take outdoor cameras right away. These cost 50€ each with my current system and deliver top images with night vision. Am I allowed to post links to cameras here? Then I could show which ones I mean.

The resolution on the Fritzfon must be 480x640 pixels. With a good camera, you have multiple streams. For example, one in full resolution for your tablet and recording, and a second one with 480x640 pixels...

Your cameras are like Dacia. They also get you from A to B, but not comfortable, slow... There are good reasons why good cameras are more expensive. Especially at night, against backlight, protection against tampering, heating, switching speed, motion detection, there are drastic differences. If you haven’t missed that so far, you can also use a cheap dome camera. And possibly also less secure. There have been some cases where cheap cameras phoned home... In any case, use an outdoor camera. It makes sense to have the cameras in their own (V)Lan and block internet access and access to your own network. Your Ctronics certainly have nothing to do with this. Cameras belong on a cable. Your Wifi (2.4 kHz) can easily be disturbed. Likewise, the app runs via the manufacturer’s cloud (do you know where the servers are?). They are also not real IP cameras with an open standard. If the manufacturer shuts down the server, your app will go dark. Continuous recording is also not possible, etc. Additional cameras cannot be integrated there. The right way is with an NVR or NAS which is set up securely with external backup, cameras on a LAN cable. Either buried or protected by a pipe. Access then via the NVR.

Links are not allowed. But you can simply post the designation.

So with my current cameras I have one stream in 1080p and one in 640x480.

As I said, I am completely satisfied with the cameras so far. I live in a village. Here the door camera is more of a "oh how cool you can see which of the friends is coming" thing and less of a "there is someone bad standing at the door" story.

By the way, the surveillance cameras are connected via a fixed LAN connection - I am not a big fan of Wi-Fi/cameras. You yourself say they are very prone to interference.

The manufacturer of the cameras is based in China and the server is there as well. I firmly expect that something would be intercepted there - that’s why in the local network I also use an app that only accesses the cameras locally. For external access, I have not found a satisfactory (free) solution so far.

By the way, the current cameras record to a hard drive (about 3 days are stored) - if the door camera is added, the footage will probably be stored for about 1.75 days (approximately).

I’ll see what I can find for outdoor cameras and then post the name - but it will probably be equipment under €100.