Here’s a real power trip: make your own worlds! You’ll need a photo editor that lets you map your photo into ‘polar coordinates’.
I use Photoshop to get this fun effect, because it has a distortion filter to project the picture pixels into polar coordinates, which is called “mapping”. The ‘planet’ effect won’t work for all subjects; you need to preplan what you shoot to help yourself out.
I will typically start with shots that I stitch into a panorama, although the effect can work with a single photograph, too. Try to find a subject that has similar characteristics on both the left and right sides, such as the same height of sky and foreground.
You will be doing yourself a favor if you use manual exposure for stitched photos, so the light will balance best between the opposite sides of the final merged photo.
A really crowded planet
Let’s begin with a panorama that has roughly matching left and right sides. While I shot the original sequence, I was trying to visualize how well the opposite sides of the view would wrap around and touch each other.
Start with a balanced shot
I was careful to avoid allowing the main subject matter to extend to the top of the frame, because it will cause an ugly effect that would be difficult to blend after mapping the shot into polar coordinates.
I arranged for both the sky and the water in the shot above to be reasonably easy to blend together, making it a good candidate for the planet effect. The left and right sides of the panorama have about the same height of sky and water, and their brightness is similar, too.
Make the image into a square
Before you can convert into polar coordinates, the picture needs to be in a square format, so you need to make the image width match the image height. Make sure the “Constrain Proportions” isn’t selected.
Turn the image upside-down
You will also need to rotate the square image 180 degrees prior to conversion into polar coordinates. If you skipped this step, you would end up with a “tunnel” effect instead of a “planet” effect. You should try leaving the shot un-rotated sometime to see what happens; there may be subjects where a tunnel effect looks good.
Map the upside-down photo into polar coordinates
Now you can convert your picture into polar coordinates (from rectangular coordinates). Click Filter | Distort | Polar Coordinates. Make sure the image scale is small enough to preview the conversion effect (click the little “minus” button).
Smooth the seams and picture frame edges
Now, you’ll need to use the “healing brush” to get the seams and edges of the frame to blend well. There are always some edge spokes you need to tame. You might use the clone stamp here, too.
This is where the real effort takes place. It can take a fair amount of finesse to blend the seams to get the shot to look good. Pre-planning your original photos will help minimize how much time and trouble there is to blend the final picture.
Rotate 180 degrees to get right-side-up again
Now rotate the picture to get it back to the original orientation. You can of course rotate any amount and then crop the shot to your desired proportions, too. Truth be told, I did a little extra 'healing brush' work after what's shown above using Zoner Pro. I like its more sophisticated healing brush tool a bit more than the one in Photoshop. I don't think any single photo editor is the best at everything.
There you have it! Your very own planet. Go easy on this technique; a few planet shots are fun, but turning everything into a planet is a bit much.