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Choderboy wrote:
Wiki: "The depth of field (DOF) is the distance between the nearest and the furthest objects that are in acceptably sharp focus in an image captured with a camera."
Acceptably sharp. Acceptable to who?
DOF, in reality, is never larger than a single plane, or a single point.
Stopping down, or using a small aperture, only allows us to perceive DOF as larger.
Using a DOF calculator, it's not like a few pixels before calculated limit are sharp and then blurry after it.
You can read about DOF and 'circle of confusion' will be mentioned, and things like 'assuming a print size of 8x10 viewed from xx distance etc', but are you going to use a print to judge?
Most important is to understand it's not a binary thing. Further, your own eyesight is a variable.
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To be a bit more precise, only one plane is in perfect focus for rectilinear lenses, which iencluds "most" lenses (I believe fisheyes may differ). BTW: same's true of our eyes, but the way the eye-brain system works, the eye is continuously moving and the brain instantaneously integrates all the views to give the illusion of everything being in focus. But if you look at a scene and are very careful not to move your eye or shift "focus" to something else in the scene, you'll notice that only the center of the scene is in focus and the rest is pretty blurry.
You hit it the reference for "acceptable sharpness" with "circle of confusion", which is the basis for describing sharpness. With a DoF calculator, you can vary the circle of confusion value, which in turn changes the perceived DoF in the image.
With all of that, though, I think it's really gotten to the point that the DoF captured in the image is less important than it used to be, because the illusion of "sharp" can be changed significantly in post-processing. Indeed, cellphones automagically produce very sharp images (at least, very high DoF) using their built-in algorithms, which get better all the time. And with all the AI features being incorporated into computer-based processing apps, it's going to get increasingly easier to create just about any sense of DoF one wants (assuming of course that you've got the appropriate software).
BTW: PhotoPills has a DoF calculator and many other useful "pills". The OP might find it useful to explore how DoF changes with lens focal length, distance to the main subject, and so on.
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