Manipulating Panoramas in Flexify (optional but recommended) Flexify 2 is an excellent Photoshop plug-in. It is specifically designed for manipulating 360x180 panoramas and it's what I use all the time. In order to use Flexify properly, you need to stitch your images using Hugin first. Make sure you stitch them in Equirectangular mode (not stereographic). Once you've saved your equirectangular panorama, open your image in Photoshop and click on Filter > Flamingpear > Flexify, assuming you already purchased the Flexify plug-in and put it in your plug-ins folder. This is what Flexify will look like:
Next, select the input to be Equirectangular, and the output can be anything you want. If you want it to look like a planet, select Stereographic or Hyperbolic as the Output. Then, set the Latitude to -90, or 90 if you want it to be a tunnel. If you want to adjust the field of view (zoom), mess around with the FOV slider. Keep in mind that if you slide the FOV slider it too much one way or the other, your image will look very pixilated and distorted. Also, keep in mind that if you want this to be a square image, you will have to resize it in Photoshop (Image > Image Size) (example: change 1000x2000 to 1000x1000) before you open it up in Flexify. I didn’t do that in this example, which is why the image has a 2:1 ratio and not a 1:1 ratio.
Trick Photography and Special Effects - 14.14.2011 - Copyright 2011 Evan Sharboneau – Page 125