Optimum focus settings and f-stops for landscapes

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JimKasson
JimKasson Forum Pro • Posts: 24,742
Optimum focus settings and f-stops for landscapes
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Based on some of the discussions that have taken place on the MF forum, I've just written a program that takes as inputs:

  • Lens focal length
  • Sensor pitch
  • Sensor fill factor
  • Sensor height in mm
  • A list of the distances to important objects in the scene
  • A list of the weights applied to those objects

The program spits out the optimum f-stop and lens focal distance setting, balancing DOF, diffraction, and sensor pixel blur to minimize total blur. It does not consider lens aberrations, which are usually small at the f-stops usually used for landscapes. The present version of the program also plots image blur vs subject distance at the calculated optimum settings, and plots the locations of the distances used in the optimization.

Right now the program runs under Matlab. If there's sufficient interest, I might consider producing a version that would run on a phone, possibly using Excel. To make practical use of this in the field, you'd need a laser rangefinder. If someone wants to turn this into an iPhone or Android app, I can supply the Matlab source code.

Here are some links to discussions of the tradeoffs of diffraction and DOF, an introduction to the optimizer, and a real-world example.

https://blog.kasson.com/nikon-z6-7/choosing-f-stops-and-focus-distance-for-landscapes/

https://blog.kasson.com/nikon-z6-7/optimizing-f-stops-and-focus-distance-for-landscapes/

https://blog.kasson.com/nikon-z6-7/optimizing-aperture-and-focus-distance-an-example/

Jim

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