HDR for HDRI

It is possible to paint with HDR images to create a HDRI in the blender?

Please do not delete this post, I need that

Do you mean like a blurred background or an actual photo being distorted?

Painting with HDR just as is done in HDR Light Studio, already I saw a video about it, but ta impossible to find this video again.

You possibly mean an equirectangular HDR (32 bit exr) image
Cycles always renders in 32 bit. Camera can be set as panoramic and you’ll find a few formats there (equirectangular among them)
So far so good.
Meaning, you can construct any scenario and just render the map.

Assuming we have some 32 bit photos (using a fisheye lens) and we could project them on a sphere (when a panoramic camera in the center)… How to paint those images on the inner surface of this sphere? How to shoot these photos? How to stitch these photos…
There are more. Just thinking about all these a few days back (coincidence).
It might be possible with the appropriate tools.

Open source software is out there and it’s great and advanced. Not out of the box but it’s rather expected from an open source app.

BTW, a little out of topic.
Blender can create seamless and tile-less textures from photos. By using tex painting and a simple setup.
The benefits are: You can test it in real time. Have a clear vision of what you’re doing. Pshop and gimp not so great you see.
Not many know that, though.