Codec after effects

Dear friends, someone can help me?
I use after effects to edit and render my video but I have problems.
I chose only mov format. I chose or photo jpeg or h264. But, with photo jpeg I have got no problems but the final file is really really big, so, it is a big problem. If I chose h264, after effects show an error banner (error with the dimensions 1 PAR) and tell me I have to edit the dimensions, from UHD to HD. I really don't know. Someone can help me?
Thank you.

H264 should be able to handle UHD but you have to adjust some of the more detailed options.

Perhaps these presets can work for you as a start - you'll have to increase the bitrate though:

https://blogs.adobe.com/VideoRoad/2012/12/4k-presets-for-adobe-media-encoder.html

Thank you very much my friend. Do you think is better to take h264 codec or photo jpeg?

Also thanks from me !

:) but, what about bitrate? If I shot 4k 30 fps or 25 fps, what about bitrate I should have use???? For a best quality/dimensions.

Regarding the big files problem - I use video converter after rendering to make them smaller. I hope it doesn't make my works worse, as I just don't know any other way out.