Depth of Focus question?

I was curious. I know 1 stop difference results in most things changing by a difference of 2 times. Such as f4 is twice as fast as the next stop f5.6 or ISO 100 is half the sensitivity of ISO 200.

Does depth of focus change by double as the aperture changes. And similarly out of curiousity is does anyone know if the diameter of the aperture double/halve as well.

Just wondering if anyone could answer these questions before I begin the process of actually searching.

Rankinia

To answer your questions: no and no.
If you want to have fun with DoF calculation, go there: http://www.dofmaster.c​om/dofjs.html

Question 2: The area of the aperture doubles or halves.
Since A=pi x r^ the radius has to change by a factor of 1.4 in order for area to change by a factor of 2. That is why the f-stop series is 1, 1.4, 2, 2.8, 2, 5.6, etc.

tzalman wrote in post #5125393
Question 2: The area of the aperture doubles or halves.
Since A=pi x r^ the radius has to change by a factor of 1.4 in order for area to change by a factor of 2. That is why the f-stop series is 1, 1.4, 2, 2.8, 2, 5.6, etc.

Correct, but the question was "does the diameter doubles or get divided by 2" and to this the answer is no. It changes by a square root of 2 factor.

Thank you both for answering. Time to play with the DOF calculater. It makes sense that the aperture area doubles. Thanks again

Rank