Calculating and making use of the lens’ 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 DOF and aperture.
Another method I’ve read about but not tried is called the “Double the Distance” method. In this technique, you calculate your distance to the nearest object you want sharp, then double it that distance, and that is where your hyperfocal distance is.
Don’t forget that you can see an accurate view of the depth of focus with your camera’s depth-of-field preview (aperture preview) button. This button “stops down” the lens to your chosen aperture. You can see the depth of field change as you open and close the aperture, allowing you to examine 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 the DOF button is held down, the screen gets darker, which can be a problem. Looking through the viewfinder rather than the LCD makes this easier since more ambient light is blocked.
If you prefer, there are also many apps for smartphones that have accurate data for various camera, lens and aperture combinations that will help and are an excellent choice for more technically oriented photographers.
Now, let me get to the reason I got started discussing the whole depth of field issue. For a few years, when I’ve found the need, I started using focus bracketing when I’m dealing with extreme near/far differences. This technique is especially useful with macro subjects but also landscapes where no aperture is capable of capturing full sharpness near to far. I make small shifts in focus throughout the near/far measurement for as many frames as needed for the given depth. Next, I use Helicon Focus or Zerene Stacker applications to blend the multiple frames into a fully sharp photograph.
The 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 in their latest models. I want that for my camera! I would use it often in my macro work and also telephoto landscapes.
There is a creative reason behind my interest in ways to gain 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.
My “Merced River Reflections” was taken at 400mm with my Sony 100-400mm 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, with my very sharp lens showing a minimum of resolution loss.
I am also sharing my “Dogwood in Bloom” image here, taken a couple of years back using focus stacking and a grid of multiple frames stitched in Photoshop. I used 12 frames to make this photograph. I took four frames for focus-stacking—focusing from the frontmost blossoms to the cliffs behind them—for each of three compositions. Then the three focus-stacked frames were pano-merged to create a nearly square image. 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 well in, and it matches the quality of the 4×5 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.