Lesson Of The Month
The Power Of Layer Masks

Ben Clay/Web Photo School, December, 2003

1 Photos © 2003, Ben Clay, All Rights Reserved Taking macro shots can be quite fun, particularly if you’re shooting some interesting subject matter. It’s good to remember that there are times when your depth of field can get so shallow as to throw parts of your subject out of focus, especially if you’re using a macro lens attachment and shooting with your aperture wide-open. You can remedy such situations by blending some camera and digital editing techniques together to ensure that your subject will be in sharp focus while maintaining the overall look of a limited depth of field shot. Here, I’ll illustrate how to achieve such a look.

2 Recently, I came across a beautiful grasshopper and thought that with all of its color and stark lines that it would make a great subject for a macro shot. I quickly grabbed a plastic container and trapped it on the outside table where it had landed. I then decided to replace the plastic container with a clear glass vase so that I could take some pictures of it without having it hop away. I rinsed out a glass vase and carefully swapped out containers. I then mounted an Olympus E-20N digital camera to a lightweight tripod horizontally and positioned it close to the glass resting on the outside table. I then attached an Olympus Macro Lens Attachment and adjusted the distance between the camera and the glass so that the grasshopper would appear as large in the frame as possible (#1).

3 I then made some adjustments to the camera. I set the Exposure mode to Manual; the Focusing mode to MF; the ISO to its lowest setting (80); the Resolution to SHQ; and the White Balance to Daylight to match the color temperature of the sun (5500K). Since I wanted a short depth of field, I set the aperture to f/2.4 and the shutter speed to 1/500 sec. To get the grasshopper to appear in the frame the way I wanted, I simply rotated the vase until it appeared in the right spot (#2). I took a bunch of shots from different angles and the glass vase worked wonderfully to render the grasshopper in (#3).

4 After a while, the grasshopper jumped off of the wall of the vase and onto the table surface. I really wanted to get a shot of the grasshopper without the vase in the shot, so I positioned the camera to get a 3/4 view of it and set the focus on the antennae. With my finger on the shutter, I lifted the vase and took a shot (#4). Looking through the viewfinder, I realized that from this angle, I probably wouldn’t get the grasshopper in full focus from front to back with my aperture set to f/2.4. I could have changed the aperture setting to achieve a deeper depth of field, but I also wanted to have the foreground and background to be very soft (out of focus), so as to draw the viewer’s attention directly to the details of the grasshopper. So instead, I decided to try a different approach.

5 Without moving the camera, I refocused the lens so that the hind legs were in sharp focus and took another shot just before the grasshopper started feeling camera-shy and “hopped” away (#5). Sure enough, once I had uploaded the images into Photoshop, the shallow depth of field was very noticeable. In the first shot, the front half of the grasshopper was in sharp focus and in the second shot the rear half was in sharp focus.

6 So I decided to merge the two images together using a Layer Mask technique. With the two images side by side, I selected the Move tool and dragged the second image on top of the first. To make sure the images lined up as close as possible, I set the opacity of the top layer to 50 percent so that the bottom layer would be revealed at 50 percent as well (#6). Once the two images were lined up, I set the opacity back to 100 percent and then clicked on the Layer Mask icon (second icon from the left at the bottom of the Layers Palette). With the Layer Mask activated, I could then use a soft-edged paintbrush to paint over and reveal sections of the bottom layer. I set the top color swatch to black, chose a soft-edged paintbrush, magnified the image to 100 percent, and carefully painted over the blurry sections of the top layer to reveal the sharp areas of the bottom layer (#7).

7 Once the grasshopper appeared sharp from front to back, I saved the layered version (in case I ever wanted to go back and make more adjustments), then flattened the image by choosing Layer>Flatten Image, and saved a flattened version. The final result shows a seamless merging of these two images to render the grasshopper (or in this case “glasshopper”) tack-sharp while maintaining a very short depth of field. If you would like to continue your digital step by step education lessons on editing, printing, and e-mailing your photos it will be on the private section of the Web Photo School. To enroll for WPS just go to www.shutterbug.net and click on WPS Free Lessons.