With a DxOMark score of 19 points mounted on the Panasonic GH-2, the new 17mm shares a similar level of image quality to the firm’s ED-equipped 12mm f/2.0 (24mm equivalent). If we look more closely at how that benchmark was achieved we can see that the 17mm can’t match the wider lens for sharpness, especially in the centre (from f/2 to f/5.6), which is somewhat disappointing. Distortion isn’t as well controlled as it might be and, as with the 12mm, is noticeable in certain images. Perhaps the most significant shortcoming is the very high levels of chromatic aberration, which is apparent at all apertures in the outer field.
Compared with the firm’s tiny 17mm f/2.8, the new lens promises much higher imaging performance although with just a cursory glance at the individual scores it may not be appear so. It’s not only due to the superior sharpness across the field but that the new lens achieves similar scores while being significantly faster (and therefore more difficult to correct). If the new lens only had lower chromatic aberration, it would achieve a much higher score overall.