I was at Viera Wetlands yesterday and came up on this scene. The pair of birds was about 30 feet away and I was using a long telephoto lens (Sigma 150 – 500 OS, @ 500mm) and shooting hand held. To keep my shutter speed high (1/1000 sec), I had my aperture set to f/8.
Under these conditions, the depth of field (DOF) was so shallow (about 6 inches) that I couldn’t get both birds in focus at the same time. I could have stopped down to f/16, which would increase the DOF to about 12 inches, but that still might not have been enough – and the risk of motion blur would increase when the shutter speed slowed down.
So how can you overcome such shallow depth of field? Here’s how I did it:
- Make two exposures, one focused on the front bird and one focused on the rear one.
- In Lightroom, do your preliminary adjustments so the images’ appearance matches as closely as possible. You want to keep the background around the birds as similar as possible in the two images.
- Open both in Photoshop, and move them into a single file as layers. Put the base image (the one with the front bird in focus) in the background layer. The top layer then has the rear bird in focus.
- Select both layers and use the Edit/Auto-Align Layers to line things up.
- Insert a Layer Mask (hide all) on the top layer.
- Now you’re all set to paint the in focus rear bird into the image with the front one in focus. Select the layer mask and use a white brush color to paint the rear bird in. If you make a mistake or need to back something out you can change your brush color to black to erase the top layer. You can also play with the brush hardness and opacity to feather things in.
- Once you’re happy with the result, flatten the image and make your final adjustments.
“But Ed,” you say “isn’t this cheating?” It depends. If you’re a photojournalist reporting on Great Egrets in Viera Wetlands and how close they often come to each other, then yes it might be. Journalists must meet ethical standards. On the artistic side, you’re trying to represent what your eyes (which have a greater DOF) or mind sees. So in this situation it isn’t cheating. You’re using the tools available to make the image you want.
“But Ed,” you say “this is too much work!” It depends. Some images are worth the effort and many are not. There’s software you can buy to automate this sort of thing for you. Photoshop can do it too. But the automated software requires very careful set up and in most cases a tripod, and many exposures with small changes in focus for each one. In this situation, I only needed two photos, one for each bird. Alignment between the images isn’t critical since I’m only using a small portion of the second one. So it’s fairly easy to show the pair of Egrets and not be distracted by having one out of focus.
You can see more of my Viera Wetlands photos in this set on Flickr.
For comparison, here’s the original photo straight out of the camera:
Quite a dramatic change, and for me worth the effort. What do you think?
©2010, Ed Rosack. All rights reserved.