Addon for Blender to maintain a camera's focal length/distance ratio.
See promotion video here: https://youtu.be/db8TEAO8qDM
See a video explaining how to use it here: https://www.youtube.com/watch?v=6pBx33feU4c&lc=UgyskxmQ_82Gvtjy8gp4AaABAg
Note: if you are experiencing trouble installing the addon, please click > Code > Download ZIP. And then unzip the file. Go to Blender and install the Python file that is in this unzipped directory.
Windows 10 21H2 Downloaded the zip file and unzipped it. (Ensured unzipped - examined the .py in VS Code) Installed in Blender. Add-on list disappeared. Renamed ...3.0 to 3.0_bak. Recovered Add ons.