Originally posted by wombat2go Do the LensTip.com graphs cited by Jogiba show that the Pentax lenses are sharper or vice versa?

They show the MFT lenses as being sharper at wider apertures. dxomark shows similar results and they scale results to be directly comparable.

The graphs can be used to compare the sharpness simply by dividing the MFT numbers by the crop factor relative to APS-C (1.37), which makes the 60 lpmm results a bit higher than the 40 lpmm results for Pentax - 43.8. The lpmm measurement implies lines resolved per mm of sensor size.

Math is easy:

Let M be the lpmm for MFT, A the lpmm for APS-C, WM the width of the MFT sensor, WA the width of the APS-C sensor. Then if you shoot the same scene with equivalent focal lengths, you need to compare the resolution given by the MFT sensor (M*WM) with that given by the APS-C one (A*WA) - i.e. how many lines the sensors could resolve overall.

M * WM compared to A * WA

is equivalent to: M compared to A * WA/WM

which is equivalent to: M compared to A * crop factor (23.7/17.3 = 1.37)

or A compared to M/1.37 - MFT numbers need to be divided by crop factor

Note that the crop factor of the MFT sensor compared to APS-C is smaller than that of APS-C compared to FF. I compared the widths of the sensors, assuming we crop the vertical of the MFT images to get the same format ratio that APS-C has. But the difference between these two formats is even smaller than the crop factor suggests.

Here is a comparison of sensor surfaces:

FF surface: 864

APS-C surface: 370

MFT surface: 225

FF to APS-C ratio: 2.33

APS-C to MFT ratio: 1.64

Source:

Image sensor format - Wikipedia, the free encyclopedia