Why do cameras go in and out of focus? Why can’t everything just be in focus?
In: 3
Some types of cameras can always be in focus, but the problem of focus comes from the physics of how your typical camera works.
In short, a large three-dimensional space must be projected onto a small two-dimensional image (the sensor). This is typically achieved by a combination of lens and mirrors. Let’s focus on the lens as the main mechanism.
The focus depends on the type/curvature of the lens, the position of the object, the position of the lens, and the position of the sensor. Notice that of these, when we move the focus ring, we only change the position of the lens. At an appropriate position for a nearby object, the far-away object is no longer properly focused; and vice versa.
The imagery here helps to illustrate this:
https://www.bhphotovideo.com/explora/photography/tips-and-solutions/how-focus-works
Latest Answers