New answers tagged calculations
Wikipedia has all of the DoF formulae you probably ever need. You may now begin to see why optics is a field of physics unto itself. You aren't going to be able to learn these equations and do them in your head to map an ƒ number to a depth of field in, say, feet. This is why there are so many DoF calculators floating around. I wrote one of many.
The math on two fstops is the square root of the sum of the two squares, but I don't know about EV. If the lights were equal, and if they lighted the same overlapping area, twice the light is one stop additional. But you say the ambient is 3 stops down from the lamp, so it won't have much effect. This ambient adds less than 0.2 stop increase, not over ...
It is really rather simple. The diopter value will tell you how close you must be to the subject of your photograph, the farthest distance you can get a sharp image with the close-up lens on. you divide one metre by the diopter value to get the distance, which is the focal distance of the close-up lens. Hence a +1 lens will give a far distance of 1 m and ...
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