This is my design of a raspberry pi camera (compatible) support to picture the nozzle as close as possible in the CR-10 frame,
There are a lot of compatible devices, for comfort those you see in the picture are:

• Raspberry PI compatible Camera with fish-eye lens, bought in banggood
• + IR light beside the camera, banggood
• + 2m Rubber cable, AliExpress

Update: added cr10-raspicam-z-3.stl (more solid version and grab better to frame)

This design idea supports the camera with a minimal amount of filament, print two of them

I didn't find online a mount for the raspberry PI camera on CR-10 for close up, there are some even very popular but their resulting picture is from far, so I look where I could place the camera closer... The E3D nozzle do not give much space for a camera coherent to the extruder (I previously made a support for a geetech Prusa I3x coherent with the nozzle that permitted picture even closer than how I found possible in the CR-10.
Well there is a space on the back of the extruder of the CR-10 frame. The bottom wheel is somehow on the way across through but can be avoided (as I designed).
The frame has also a shape that something can grab on it without need of screw, in the back frame that has a good vision because the nozzle has more visual access, I also have fortunately a window on the back of the printer which project light from the best direction, but I discovered later that in full dark in the night the infrared illumination is sufficient to capture perfectly visible images (even too bright illumination in full dark).
I also don't like screw so I invented and designed that mechanism to grab to the frame, printing two of this support is sufficient to have the camera work properly. The way this grab can be improved, I'm happy enough, but if you have some difficult to grab the hook to the frame let me know in the comment, I recommend to press firmly toward the frame starting pressing a bit downward initially and consider that the top of the arrow alike hook is thicker to hold permanently the weight of the camera and infrared.
The raspberry pi camera ribbon cable is left oriented toward the top of the printer or fixed together the black cable that goes toward the extruder. the mimimum lenght is possibly more than the standard cable (I provide a link to buy longer ribbon cable, I'm not sponsored by those links and I'm in doubt if it is the case to publish them).
Let me remark that the flexible grabbing to the CR-10 frame is my idea, I can improve it to make it even more effective (pressing the clip to insert and release to the frame) and if you reuse the idea please leave a pointer to where you sourced it (this my thing, thanks to keep recognition).

The two infrared light are those big black cylinders the camera is between them, all of this shape is not interfearing on any movement of the CR-10 axes. The picture above is seen from beside while printing Munari's spinning top, below there is the kind of image that come out closer, the camera can better regulate the focus, note also that the position of the camera produces an image upside-down because the raspberry pi camera ribbon cable goes away-up from the bottom of the camera. Octoprint in the camera setting has a checkbox "Webcam and Timelapse" -> "Flip webcam vertically" to adjust the upside down. Or use -if available- the option -rot 180 of the input_*.so module of mjpg_streamer (I did it after taking some of the upside-down pictures and videos)