Reading DOF Chart

RogersDA

How to read this chart: At f/1.2 and focusing @ 10m then the depth of field (range of generally sharp focus) will be between 9.42m and 10.65m.

Correct?

ziggy53

The first thing you have to understand about DOF is that it is very "ishy". There are no absolutes and sharpness is a relative term. The concept of "circles of confusion" itself is open to some interpretation.

I prefer the online DOF calculator, but it is not as scientific or as accurate as they would like you to believe. The only truly accurate method is the actual testing of lenses against different subjects and the a personal evaluation of the results to determine if the results are to "your" satisfaction and use.

http://www.dofmaster.com/dofjs.html

RogersDA

Ziggy,

Thanks for the information - pretty much knew that, but refresher information is always good.

I was primarily curious if I was interpreting the chart's information correctly - not necessarilyt that the numbers were absolutes - just wanted to know if I understood was was being shown.

That said - am I interpreting the chart's information correctly; e.g., at 10m and f/1.2 Canon's test show a range of focus between 9.42m and 10.65m (or just under 1m)? I understand my results may and will vary should I get and use this lens.

ziggy53

RogersDA wrote:

Ziggy,

Thanks for the information - pretty much knew that, but refresher information is always good.

I was primarily curious if I was interpreting the chart's information correctly - not necessarilyt that the numbers were absolutes - just wanted to know if I understood was was being shown.

That said - am I interpreting the chart's information correctly; e.g., at 10m and f/1.2 Canon's test show a range of focus between 9.42m and 10.65m (or just under 1m)? I understand my results may and will vary should I get and use this lens.

Yes, that is the proper interpretation of that table and the Canon 85mm, f1.2L. I do believe that table is designed for a full-frame camera, so a 1.3 or 1.6 crop camera should be slightly more DOF at the same distance.

RogersDA

Thanks for the information, Ziggy.