AT Play in the Digital Realms: Focus Stacking in Photography-Creating Infinite Depth of Field

One of the biggest challenges in photography has always been maintaining sharp focus from the foreground to the background in an image. In the past, this required either using the smallest aperture possible like f22 on SLR’s or getting out the big 4x5 camera.

With macro photography, the problem is multiplied because even at the smallest apertures, the plane of focus is so very narrow. The closer you get, the narrow it becomes, often just millimeters.

A 4x5’s ability to change the perspective by using swings, tilts and shifts of the front and rear standard in conjunction with f32, 45 or even f64, allowed photographers to keep everything in focus from a subject inches from the lens to mountains in the distance.

Once again, I say an emphatic Hallelujah! for digital photography. Lugging around a heavy 4x5 camera, the film holders and a big heavy tripod, not to mention the other accouterments, like light meter, dark cloth, loupe, lenses etc. was always a major ordeal. Sure the quality from a 4x5 inch piece of film was incredible, but hiking miles into the best spot was at best, a labor of love.

Ansel Adams, the great master, did it as did so many other great artists even up until today. They even started a movement called Group f64.

You’ve seen the caricature of someone behind a big camera looking through the ground glass beneath a black cloth. Well, what you didn’t see is the person beneath the cloth first composing the faint upside down and backwards image on the rear ground glass and then using a magnifying loupe to carefully inspect the focus. Then of course, they had to make their shifts and tilts, re-compose, check the focus, etc. ad nauseum.

Been there, done that. And I can’t laud enough praise on today’s cameras that give me far greater ease of use along with extremely high quality. Not to mention weighing significantly less.

But still, the problem of keeping things in focus from front to back is still there. Sure, you can use the smallest apertures, but the sharpness gets degraded as you close down. Plus, every lens has a sweet spot where it’s sharpest. My 28-300 Nikon is sharpest between f9 and f11.

So what if I could use my sharpest aperture while keeping everything from front to back in focus? What if you can do that on the tiniest of subjects, in this case, the center of an iris.

Enter Focus Stacking. It has to be done on a tripod and using manual focus. Whether you’re shooting a landscape with a close foreground and distant mountains or a flower, simply take a series of exposures with varying planes of focus. First focus on what’s closest to the camera, then focus on something a little further back, focus farther still and finally take a shot of the most distant part of the composition. This can take two to however many shots, but usually 3-5 will suffice.

Make sure all the photos are shot at the same aperture otherwise things will get really screwed up. And of course, make sure the exposures are all the same, the camera and zoom don’t move and the wind isn’t blowing

After downloading the images. Open them in PhotoAcute, Helicon Focus, Picolay or Zerene. These programs do a reasonable job and prices vary from free to $149.

Photoshop also does a good job. With PS, which is what I used here, select the photos in Bridge and go to Tools/Photoshop/Load files into Photoshop layers. Photoshop opens the photos as layers. Select all the layers. Align the layers under Edit/Auto-align layers/Projection Auto. Then use Edit/Auto-blend layers/Stack images. Flatten the layers when photoshop is finished and prepare to be amazed.

Here are the four shots I used. You can see how narrow the planes of focus are in each. The finished shot is both at the top of the blog and below the others.