For years, photographers relied on the depth of field scale to help them achieve better focusing results. It was used in combination with a system called the Zone Focusing system, otherwise known as hyperfocal length shooting.
Then autofocus was developed and for a while, effective depth of field scales disappeared on autofocus lenses. While autofocus algorithms have come a long way, many of us still really love using that depth of field scale–and by many of us I’m talking about the street photography community that many lens manufacturers sometimes target with specific products.
So why do we need zone focusing and a depth of field scale? The answer is simple and has to do with the way that zone focusing can be superior to autofocusing.
While autofocusing algorithms have really improved and the speed is certainly nothing to complain about, a skilled photographer can still focus faster on a subject and capture an image than someone fumbling with choosing an autofocus point, trying to frame and get their exposures right.
Some companies have jumped on board: Olympus with their wide angles, Fujifilm with their wide angles, Zeiss with almost everything they have, Leica with mostly everything, Voigtlander, etc. Truth be told, an effective depth of field scale give us a chance to capture a moment much faster because of the way that using one makes you use the camera/lens and how you see the world.
If I’m shooting at f8 with a 35mm lens and focused out to around five feet away from me, chances are that I’ll get somewhere between four feet and six feet in focus. That means that when someone or something is within four to six feet away from me, it’s possible for me to capture that scene even while that person is moving through the designated area–and capture them sharply enough to make a visual impact on an image without having to zoom in to 100%.
The photographer also learns to see the world and think in terms of that focal length.
With autofocus, I’ll need to ensure that my specific focusing point is selected and then more or less track that moving person. If the camera is told to just choose any focusing point, I probably won’t get the shot.
In a situation like that, it would be significantly simpler to have a depth of field scale on the lens–not by using the LCD screen the way that some manufacturers offer. Yes, that’s a nice addition, but it’s still not absolute.
This is something that I mention in every review and for many of us, it just makes sense.