Sharpness at 20mm

For this test, the Panasonic Lumix S 20-60mm f/3.5-5.6 lens was attached to a Panasonic S1R body, which was in turn mounted to a sturdy tripod. Exposure delay mode was activated and image stabilisation turned off. Tonal and colour variance across the crops are due to change in natural light during the session.

The full frame at 20mm

At 20mm, the maximum aperture is f/3.5. In these test images we can see that detail is sharp across the entire aperture range, save for f/22 where the effect of diffraction (an overall softness) is seen. We have to say though, that even at f/22 the overall softness is only really visible when really scrutinising a picture. There is an ever-so-slight softness at the maximum f/3.5 aperture, but again you have to strain to see it.

Perhaps what is most impressive is how centre sharpness is maintained pretty much all the way to the very corners of the picture. In real world images there are other factors at play effecting corner sharpness, namely shallow depth of field especially at the more open apertures. But at a level plane to your subject, detail is sharp in the entire frame.

Our hyper critical observations would confirm that the sweet spot of the lens at 20mm is between f/5.6 and up to f/11, but we would have no hesitation to use this lens even at its maximum aperture if sharpness is the main concern (there are lens distortions present at f/3.5 in chromatic aberration and vignetting).

Truly though, we have been surprised by just how sharp this lens is. It's not critically sharp in the same way as lenses three times the price, but it is very sharp indeed!

Aperture	Centre Crop	Edge Crop
f/3.5
f/4
f/5.6
f/8
f/11
f/16
f/22