DOF question for you pros

Snydremark wrote in post #12524854
Correlation does not equal Causation.

This has nothing to do with Correlation or Causation. This is maths. When the hyperfocal length is not a significant factor, the maths can be simplified.

It only makes sense to talk about framing the subject in the same way, so of course changing the focal length requires changing the camera-subject distance.
However, only the size of the framed subject and the aperture affect the DOF.

Why include an input to a calculation that does not affect the output? Such an input is REDUNDANT.

Yes, you can keep with the more complicated maths, but what I'm saying is, you don't need to. You can make things simpler, and make is easier to think about it.

I get the impression that the DOF calculators are so ingrained as the only way to calculate DOF that there is automatic resistance to any other way.

CaptivatedByBeauty wrote in post #12524665
Nope, it's not informal, it's an easier method. You only need focal length and distance if the hyperfocal length starts to become significant....(etc)

Interesting. I don't really bother with tables or charts, I just know what'll usually work for me and go with it, you learn over the years

tim wrote in post #12527653
Interesting. I don't really bother with tables or charts, I just know what'll usually work for me and go with it, you learn over the years

this.

CaptivatedByBeauty wrote in post #12527453
This has nothing to do with Correlation or Causation. This is maths. When the hyperfocal length is not a significant factor, the maths can be simplified.

It only makes sense to talk about framing the subject in the same way, so of course changing the focal length requires changing the camera-subject distance.
However, only the size of the framed subject and the aperture affect the DOF.

Why include an input to a calculation that does not affect the output? Such an input is REDUNDANT.

Yes, you can keep with the more complicated maths, but what I'm saying is, you don't need to. You can make things simpler, and make is easier to think about it.

I get the impression that the DOF calculators are so ingrained as the only way to calculate DOF that there is automatic resistance to any other way.

EDIT: NM, I see what you're saying. However, the way you're stating it is not really correct. DoF is determined by the 3 factors of focal length, aperture and distance to subject, period...that's the math of optics. The thing that determines how much of your subject fills the frame, at any given focal length is the subject to camera distance. So, even in your chart, you aren't throwing out/ignoring/not including that input, you're just using a different, indirect method of measuring it.