Lens•Lab Calculations

It occurs to me that some customers and potential customers might be wondering how Lens•Lab figures its calculations. In the spirit of openness, honesty, and transparency, I present to you the methods I use.

First of all, the primary sources I used for the formulas are:

Additionally, I used the following websites to either double check my calculations or to understand how crop factor influences depth of field:

Here is how I do the calculations:

hyperfocalDistance = ((focalLength * focalLength) / (apertureInFStops * circleOfConfusion)) + focalLength

depthOfFieldNear = ((hyperfocalDistance – focalLength) * (focalDistance)) / ((hyperfocalDistance + focalDistance) – (2.f * focalLength))

depthOfFieldFar = ((hyperfocalDistance – focalLength) * focalDistance) / (hyperfocalDistance – focalDistance)

depthOfFieldTotal = depthOfFieldFar – depthOfFieldNear

All distances are in mm and circleOfConfusion is set based on the sensor format:

• Full Frame = 0.029mm
• APS-H = 0.023mm
• APS-C = 0.019mm
• Four Thirds = 0.015mm

I’ve double-checked the calculations that Lens•Lab produces with other depth of field calculators and they match up.

There you have it! Questions or comments? That’s what the box below is for!