DEALING WITH DEPTH

CREATING IMAGES WITH EXTENDED DEPTH OF FIELD AND SHARPNESS

In landscape photography, we are often dealing with considerable depth of field, with objects near the camera and distant subjects off in the distance. Call me Captain Obvious! Greater distance from the nearest subject to the farthest requires the use of a smaller and smaller aperture. With each stop down, there will be a slight loss in resolution. The tradeoffs of losing resolution versus gaining sharpness near-to-far often require a balancing act. I miss the days when I could easily look at the depth-of-field scale on my lenses, read the scale to adjust the hyperfocal distance, and adjust the aperture choice. View cameras or tilt-shift lenses give greater control over near/far image sharpness, but they don’t solve the issue in all situations. Smaller apertures are still needed where various angles in the landscape don’t match the flat plane of focus given from the tilt, such as when you’re photographing in a level meadow with tall trees in the distance.

Calculating and making use of the lens’s hyperfocal distance is usually your primary solution. There are many ways to handle depth of field and many opinions on the best methods. If you are using manual focus, you can focus about one third into the depth of the scene, and guesstimate which aperture will bring both near and far points into focus. If you are using autofocus, you can select the focus point in your viewfinder at the estimated distance in the same manner. I’ve used this approach for many years, often bracketing apertures to help me find the best balance of depth-of-field and aperture.

Another method I’ve read about but have not tried is called the “Double the Distance” method. With this technique, you calculate the distance to the nearest object you want to be sharp, then double that distance, and that’s where your hyperfocal distance is.

Don’t forget that you can see an accurate view of the depth of focus with the depth-of-field preview or aperture preview button. This button “stops down” the lens (digitally or actually) to your chosen aperture. You can see the depth of field change as you open and close the aperture, allowing you to see what will be sharp or not. On my Sony camera, I set up a custom button to be my aperture preview button. Not all cameras have this preview button, so check your manual. Being able to see the results of your aperture choice makes this a valuable tool. When this button is held down, the screen gets darker, which can be a problem. Looking through the eyepiece rather than the LCD makes this easier, since more ambient light is blocked.

There are many apps for smartphones that have accurate data for various camera/lens/aperture combinations that can be helpful. These are an excellent choice for more technically oriented photographers.

Now let me get to the reason I started discussing the whole depth-of-field issue. For a few years, when I’ve found the need, I started using focus bracketing when dealing with extreme near-far differences. This technique is especially useful with macro subjects, but also with landscapes where no aperture is capable of capturing full sharpness from the foreground to the background. I make small shifts in focus throughout the near-far measurement, for as many frames as needed for the given depth. Next, I use the Helicon Focus or Zerene Stacker applications to blend the multiple frames into a fully sharp photograph.

This technique is very effective, but also a bit tedious to execute in the field. Focus and click; shift the focus a tiny bit; click; focus again—clicking 5, 10, sometimes 15 frames. I’ve used this technique only occasionally. What got me excited recently was seeing that many camera makers are now offering an automated approach to focus shifting. I want that for my camera! I would use this often in my macro work and also telephoto landscapes.

There is a creative reason behind my interest in gaining full sharpness in a scene or subject that has great depth. I like mystery in my photographs. I like strong design too. When I look for the graphics in a scene, I often like to combine the two qualities by making everything in the frame sharp, especially with intimate landscapes where there are fewer visual clues, like the sky, for example. When this approach works, the depth is not immediately apparent, and it becomes a visual pun or play on one’s perception. Such flattening of the perspective can add a bit of intrigue that engages the curiosity of the viewer.

Merced River Reflections was taken at 400mm with my 100–400mm Sony lens that serves to “flatten” the long stretch of riverbank depth into a flat-looking composition. My use of a small aperture gives near-to-far sharpness, with the curved grasses and their reflections receding across the frame, and my very sharp lens shows a minimum of resolution loss.

I am also sharing my Dogwood in Bloom image here, which was taken a couple of years back using focus stacking. I took four frames, focusing from the frontmost blossoms to the cliffs behind them, then I merged them using Helicon Focus software. Every blossom is sharp in spite of the great depth, from the frontmost blossoms all the way back to the cliffs behind. I have a long-standing theme of forest tapestry photographs that this fits into quite well, and it matches the quality of the 4x5 film images in that group.

The next time you find yourself dealing with difficult depth of field and sharpness dilemmas, give the tools discussed here a try. Stay sharp. Stay creative.

Dogwood Trees in Bloom | Yosemite National Park, California | 2017

Dogwood Blossoms | Yosemite National Park, California | 2019