Distort an image for a fun warped look!
The idea of the fisheye lens is to be able to capture a wider angle of view than a standard lens. But it differs from a wide angle or panoramic style in that the fisheye projects the image into a circle in the frame!
Begin by going to Image>Size. Make sure the Constrain Proportions box is cleared, then enter a Width value to match the Height to ensure the image is square before you can apply the effect.
Go to Filter>Distort>Spherize and raise the amount all the way to 100%.
Create a new layer and grab the Elliptical Marquee tool. Set the feather value in the Options bar to 15px. Create a circle selection as large as you can without going outside the image. Press Ctrl/Cmd+Shift+I to invert the selection and then fill in black.