Excellent sharpness and control of flare and aberrations. Small body for its optical characteristics and compared to mirror counterparts. Reliable metal construction with moderate weight. Officially, the lens does not have dust and moisture protection. However, the focus is internal, and when zooming, the front group moves inside the body. The filter is screwed onto the body itself, and not onto the front group. This means that the protective filter will seal the zoom mechanism. The rest of the cracks, in theory, should be afraid only of very fine dust. And in the rain you still canโt shoot wide. Given the fact that the lens has a constant aperture, the absence of marks on the aperture control ring is very frustrating. In general, excellent glass, worth the money. For landscapes and interiors just right.