Centre sharpness test
I compared the 60mm macro to my 18-135 for this test. It's the only lens I have that can match the field of view and IMO, the sharpest. At it's best it is sharper than my 50 f/1.8.
Both sets were taken with the camera about 2ft from the test chart in a well-lit area with the flash fired so shake is not an issue. Rather than RAW, they were shot in JPEG - large + fine with +/- 0 sharpening added in camera so the Nikon users reading this review will have an indication of the output quality.
f/3.0, this is the maximum aperture of the 60mm at this focusing range (~2 ft.).
Sharp here and about the same as it is at f/2.8 (not included in the test). Note the slight amount of CA.
The 60mm peaks at about here. Any further increase in sharpness is too small to be noticed or for me to place any importance on. Note that the CA is now almost completely gone.
[Left - 60mm] [Right - 18-135]
So much more detail in the 60mm, the 18-135's look they have been been subject to NR when compared. The difference is quite significant although the 60mm is in it's "sweet-spot" or rather range while the 18-135 is shooting wide open. Interesting that the 18-135's max aperture is f/5.6 at 66mm making it no faster than the 18-55 and a constant f/5.6 66-135 zoom (...if that sounds better
The 60mm is still very sharp and the 18-135 is again nowhere near even though the 18-135's sharpness peaks between here and f/11.
Same result, the 60mm is tack sharp
Still sharp with no visible sign of diffraction but I would say that the sharpness begins to drop off from here onwards. Diffraction kicks in for the 18-135.
Slight drop in sharpness but I would consider it very usable and it is still about as sharp as the 18-135 at f/8!
I am, so far, very impressed with the sharpness of the 60mm. It blows the 18-135 right out of the water and although this kit lens isn't the best, it is no slouch and resolution was what I considered to be it's strong point. The 60mm shows good levels of resolution from wide open to f/22 which can be very useful when stopping down for increased DOF at the higher magnifications. Note that the 60mm's max aperture is f/4.8 at 1:1 magnification.
It was not part of the test but the crops show that the 60mm does suffer from CA wide-open. It's not too bad but I wasn't expecting the 18-135 to outperform it.
Next: Corner sharpness.
Meanwhile, here is a sample. It's not my best job at controlling the DOF but it shows off the smooth bokeh of the lens.