Ah, shallow depth of field. We all probably remember the first time we got our hands on a lens that allowed us to obscure the backgrounds of our images with beautiful, twinkling bokeh balls, instantly turning our compositions into incredible, even accidental, works of art. "I'm a visionary," we thought. And we were so right.
But the art of capturing images is much more diverse, we learned, and soon we found that subjects, when blocked with great care, can be just as meaningful and aesthetic when shot in deep focus. In fact, some of the most iconic films in cinematic history were made famous with deep focus shots, like Citizen Kane, Paper Moon, and The Bridge on the River Kwai.
In this informative video, John P. Hess of Filmmaker IQ shows you how you can capture deep focus shots by explaining, in great detail, the concept of hyperfocal distance.
Simply put, hyperfocal distance is the closest distance you can focus a lens while managing to keep objects at infinity "acceptably" sharp, giving you the deepest depth of field possible for the lens you're using. As Hess explains, the hyperfocal distance depends on several factors, including sensor size, crop factors, and the type of lens you use. To get the closest possible distance, you'll need a lens that has a:
- Smaller focal length
- Higher F-stop
- Larger Circle of Confusion
As you can see from Hess' sensor comparison, it gets really interesting when you start calculating for sensor size. Smaller sensors, like a Micro 4/3, tend to produce shallower depth of field than larger sensors, like a full frame, so if you put the same lens on each, the hyperfocal distance will be much further with the small sensor camera. However, if you account for crop factor on the smaller sensor and replace the lens with a field-of-view equivalent, then the hyperfocal distance is actually going to become much closer compared to the larger sensor camera.
If I just completely confused you/butchered Hess' explanation, check out his interactive lab on Filmmaker IQ so you can really get a handle on the concept.
Source: Filmmaker IQ