To analyze this lens, let’s first look at the spot diagram:



Next we’ll check the FFT MTF:



Note that I’ve chosen a Max Frequency setting of 100 lp/mm. This corresponds to a single-spot resolution of 5 um, which corresponds closely to the resolution required for 20/20 Snellen Visual Acuity. You can see that this model should produce a well-resolved image up to 100 lp/mm, and therefore is a good model of a 20/20 human eye.

Finally, in order to get a good feel for how well this “patient” can see, we’ll check the Diffraction Image Analysis. The diffraction image analysis feature is similar to the geometric image analysis feature, except the complex system Optical Transfer Function (OTF) is used to compute the image appearance. This method accounts for the finite pass band and other diffraction related effects real optical systems have on image formation.

For this, let’s set it up to image the letter “F” at a size that corresponds with 20/20 Snellen Acuity. Go to Analysis|Image Analysis|Diffraction Image Analysis, and then click Settings and set the values as shown below:



Here is the resulting Diffraction Image Analysis diagram: