I think you mistyped the driver name, It is not indi_webcam, it is indi_webcam_ccd. You might or might not have it installed, but if you do, that is the name of the driver. You typed the V4L2 and rpicam driver names correctly, just not the middle one.

thank you - you were right! i forgot the "_ccd" i was so puzzled about the new error that i did not see my typo.

and the best is - the RPI Cam works with indi_webcam_ccd great. The resolution is at 1600x1200 okay with less than 1s delay. if i set the resolution to 640x480 the delay is nearly gone.
if i try to set the correct resolution PHD2 crashes totally

for guiding it would work for me with this lower resolution. i wonder if the binning is working with the indi_rpicam driver? i set 4x4 binning, but nothing happened - it should be much brighter, but no effect. i would love to have the binning feature , but if it isn't working with this camera, i can use the webcam driver too and i don't have a need for the rpicam driver.

edit: and it looks like the exposure settings does not work - i can't modify the expsure time. well - i can, but it is ignored

So I don’t right now have answers to all your questions here, but true binning is a capability that most ccds have but cmos cameras technically do not. But a number of cmos cameras are capable of binning in the cameras electronics before sending the image back. A ccd usually has wiring for each column of pixels and so it reads a whole column of pixels at a time. It can bin by just adding pixels as it reads them out. A cmos camera usually has wiring for each individual pixel so if it has binning capability in its camera, then it combined the pixels after reading them out in the software of the camera. This slight difference means that when a ccd camera bins, it is as if the pixels really were bigger and helps with signal to noise ratio because the signal gets greater but the readout noise remains the same. For cmos cameras with binning capability, the new bigger “pixels” will have more readout noise along with the signal since they will have the noise from each pixel. However, with both types of cameras, if binning can be done in the camera before transmission through the wire back to the computer, the smaller image should take less time to transfer. If a camera is not capable of binning in the camera, binning can be done later in the driver or software on the computer that receives the image, this is known as software binning. But with software binning you have already lost the two advantages of binning I mentioned above. I don’t believe the raspberry pi camera is capable of binning in the camera, but I might be wrong.

Thank you much for your answer! That made it clear to me. i guess too there will only be a kind of software binning. in the data sheet of the chip ( Sony IMX477 / www.sony-semicon.co.jp/products/common/p...MX477-AACK_Flyer.pdf ) is Binning listed in the features. but no word if hardware or software based. well no benefit here for me :) i sometimes forget that this is NOT a SBIG camera for 5000$ ;)
later this day, i will play a bit with the options in the webcam driver - maybe i can make the cam with it a bit more useful and fix the exposure time bug.
(i noticed that even the indi_rpicam does not react to different expsure settings in PHD2 - maybe there is the BUG)
i will update as soon i figured it out where the problem lies.

Well I'm not sure there is a bug per se. The V4L2 and INDI Webcam driver are treating the camera as if it is a webcam. You can't set arbitrary exposures on a webcam. However, you can set frame rates and sometimes that will change the exposure time. When I wrote the INDI Webcam driver a couple of summers ago, I added a feature to it where you could set an exposure time and it won't change the cameras actual exposure time since for many webcams that is impossible, but it will stack multiple frames together either averaging or integrating them to get a better image over the longer time.

For example, if your webcam is taking 60 frames per second and you tell INDI Webcam to take a half second exposure, it will average about 30 frames together if you select that option. The resulting averaged image will have a significantly higher signal to noise ratio than a single frame. You can also integrate the 30 frames instead, but you could very quickly overexpose and saturate your pixels that way. Of course, as with a regular camera, if the subject moves during the "exposure time", then it will blur in the averaged image.

many thanks for the explanation. now the settings are clear to me
i think i will give it a shot and try it in the next clear night. (sadly very rare at this time in germany)

i will keep this post updated and it would be a pleasure for me, if someone has maybe a clue for the indi_rpicam driver. maybe all will work in a new build

thank you so far!