Adding a Fish-Eye Lens Effect to Your Digital Photos

1. Open an image that you want to appear as though it was photographed with a fish-eye lens.
2. Select the Crop tool.
3. Click at the top of the image and, while holding down the SHIFT key, drag the tool to the bottom of the image. When you hold down the SHIFT key, you constrain the cropping box to a square, which is perfect for a fish-eye look.
4. Click the Commit button on the options bar (it looks like a check box). Alternatively, you can press ENTER or RETURN.

5. Select the Elliptical Marquee tool and create a circular section that stretches from top to bottom and side to side, as shown next. Remember, to create a perfect circle, hold down the SHIFT key while dragging. Press the SPACEBAR momentarily to move the selection while creating it.

   

6. Choose Filter | Distort | Spherize.

7. Drag the Amount slider to 100, as shown here.

   

8. Click OK to apply the filter.
9. Choose Select | Inverse.
10. Choose Edit | Fill to open the Fill dialog box.

11. Click the down arrow to the right of the Use field and choose Black from the drop-down menu, as shown below.

    

12. Click OK to fill the selection.

13. Choose Select | Deselect. The following image shows an image with this effect applied.

    

14. http://tech.yahoo.com/gd/adding-a-fish-eye-lens-effect-to-your-digital-photos/191761;_ylt=Ai1X6XnIJ8v6q5uUjcw6kuYvLZA5
    

Accounting for Aspect Ratio in Digital Photography

You may notice that your digital pictures have a different width-to-height ratio - or aspect ratio, in photography lingo - than pictures taken with a 35mm film camera. Digital cameras produce images that have an aspect ratio of 4:3, and 35mm film negative produces pictures that have an aspect ratio of 3:2.

Why the difference? Well, digital cameras were first envisioned as devices to produce images for display on computer monitors, which have a 4:3 aspect ratio (as do many television screens). So matching the monitor aspect ratio made sense.

Today, however, digital cameras offer resolutions high enough to produce excellent prints. But there's a hitch: When you print a digital photo at traditional print sizes - 4 x 6, 5 x 7, 8 x 10, and so on - you lose some of the original image area because of the aspect ratio difference. (If you've ever had your digital files output at a retail lab, you've probably already noticed this change.)

Figures 1 and 2 show the percentage of image area you can expect to lose when you print your picture at 4 x 6, 5 x 7, or 8 x 10 inches. The left image in Figure 1 shows you the digital original; the darkened areas in the three remaining examples represent the lost portion of each picture.

Figure 1: A digital image (left) loses a portion of its original self when printed as a 4-x-6-inch photo (right).

Figure 2: You also lose some picture area when the photo is printed at 5 x 7 inches (left) or 8 x 10 inches (right).

This issue isn't a digital-only phenomenon, by the way. Your print lab must similarly crop away part of your 35mm film photo when making a 5 x 7 or 8 x 10 print, too. The only print size where you don't lose part of your 35mm original is 4 x 6, which has the same aspect ratio as the film negative (3:2).

Whether you're shooting digital or film, the problem has an easy solution. Just remember to include a small margin of background when you compose your pictures, as in Figure 1. That way, you won't lose any vital picture elements if you decide to print your photos at the traditional sizes.

If you're printing your own pictures, you can alternatively choose to reduce the size of your images so that they fit entirely within the 4-x-6-inch, 5-x-7-inch, or 8-x-10-inch boundary. You'll have a blank border along two sides of the photo. For this image, the patterned areas along the left and right sides of the picture represent the percentage of border needed to fill out an 8-x-10-inch print.

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