Sunday, April 28, 2013

Pro-Tip #5: Focus Stacking

On last month’s Big Sur Photo Workshop Tour I wondered upon a scene that required this technique. It’s not difficult to do and anyone with a manual focus capable camera/lens can take advantage of it, thanks to Photoshop. The scene was a small patch of Periwinkle under a group of cypress trees with an old dilapidated picket fence in the background. I took a shot at f/22 and was able to get the entire scene in sharp focus, as seen in this image,

Periwinkle Patch, Soberanes Canyon, © Greg Clure

although I like the image as a good representation of the entire flower patch and fence, I did not like the fact that the flowers appeared so small. I wanted to show the detail in the flowers which meant I needed to get closer to them as they are only about an inch across. I tried another shot, vertical this time; again at f/22 and I repositioned myself about a foot from a grouping of the flowers, and got this shot,

Single Focus Point, © Greg Clure

the foreground flowers look great but the middle ground flowers and background fence are thrown out-of-focus. Not that there is anything wrong with that as it is a perfectly pleasing image. The problem is when you get this close to your foreground even at your smallest aperture you cannot render the entire scene from near to far in sharp focus. I wanted the fence in sharp focus because it has some interesting detail I feel adds to the overall image. But, the closer you get to your foreground subject the shallower your depth of field becomes with any lens. Your simple solution is to take several images of the scene at different focus points and blend them together with software. In my final image, I used three focus points, one for the foreground flowers, one for the middle ground plants and flowers and one for the background fence and cypress trees. I used Photoshop to blend the sharpest areas of each image into a single image with sharp focus from foreground flowers to background fence, as seen here.

Periwinkle Potpourri, Soberanes Canyon, © Greg Clure

It is all automated and accomplished in a few simple steps. I use Lightroom for most of my editing work so we will start with selecting the three images there:
  1. Select all images to be blended in Lightroom, in my case, I had three images but you can have any number of images with different focus points.
  2. With your mouse pointer over one of the selected images, right click your mouse and select >Open as Layers in Photoshop. This will launch Photoshop and open each image in a separate layer.
  3. Next, highlight all layers in the Layers Pallet
  4. Next, choose >Edit>Auto-Align Layer, this will make sure each image is aligned at the pixel level. In the dialogue box, use the Auto setting for Projection and uncheck the two Lens Correction settings.
  5. Next, choose >Edit>Auto-Blend Layer, you will want to select the Stacked Images option in the dialogue box as well as the Seamless Tones and Curves option. Here's where Photoshop goes to work and creates the black and white masks for each image, white areas are the sharp areas that you will see and black areas will be hidden.
  6. Finally, combine all your layers into a single image by going to >Layers>Merge Layers
You can continue to edit your final image in Photoshop or save the image and return to Lightroom for further editing. That's it! Simple! Give it a try! For a larger more detailed verion for these images go to my web gallery,

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