I usually find after blowing out my pic in computer that at one point (where I wished to focus) image is very sharp, then as I inspect the picture I see that some more part of the image either horizontally or vertically is in focus
My doubt is When we lock the focus at certain point, Is it that entire plane(both in x and y direction) is in focus, because I see most of the times(In Macro) , focusing is either horizontal or vertical or I have mistaken, because of minute difference in distance. eg.
(In focus) | | (Not in focus ) ________|__________ (Not in focus or I have mistaken) | | | (In focus)
And I understand a general statement that higher F-number means more area of focus.