Wilt wrote in post #18386685
Please elaborate in detail about what makes the long-standing definition for assessment of DOF to be no longer applicable, rendering the DOF definition in need of redefinition in the digital photo age.
My point is that the standard definition is obviously applicable if you "simulate" the specific printing and viewing conditions dictated by it, however this is usually not the case in the digital era. Furthermore, I think that the standard definition was lacking even in the film era, because visual acuity and viewing conditions widely vary from person to person, let alone print sizes and viewing distances.
Depth of field is all about sharpness, and nowadays people assess image sharpness at the pixel level. This makes sense, as it simply binds the concept of image sharpness to the effective resolution of the camera and lens system, because that is what determines the actual image sharpness in the first place, independently from viewing conditions.
Fewer and fewer people print, as images are now enjoyed on a plethora of devices ranging from small-format phones to huge TV screens, with hugely varying pixel densities, viewing distances, and display medium contrast levels.
Add to that the fact that digital pictures are often cropped at will, and cropping is an operation which changes the DoF according to the standard definition, and you will see why the standard definition is so confusing (hence not only useless, but conterproductive) to the average digital photographer.