How do I extract 2D pictures from a 360 HDRI? https://hdrihaven.com/hdri/?h=bethnal_green_entrance So basically I am trying to extract 2D pictures from this HDRI (without any warping) so that I can use them as back-plates. Any solution?
i.e is there a way to go from this HDRI
to this single image without warping or loss of quality?
Add this equirectangular texture as world background texture as usual and render it.
By another words - go to Shader editor &gt; World tab, add Environment texture node
(not an Image texture node) and choose directory to HDR image on your drive.

Tips:

since you need only get render of BG, a Camera location doesn't matter
(would be different story if you would like to reconstruct envi)
to easy set view direction (camera rotation) it's handy go to 3D view editor &gt; Properties (N) side panel &gt; View tab &gt; View &gt; View Lock &gt; and enable Camera to View
Wrapping amount (distortion) of rendered image is equal to camera lens value. Range of view you can change in Properties editor &gt; Camera &gt; Lens &gt; Focal Length
use the highest hdri resolution available, since final render use just a portion of the texture, it is possible it would not be enough for backplate in some cases anyway :)
since source texture is high dynamic range (HDR) image it's useful to keep Color Management &gt; Filmic with some Look preset or adjust contrast later