Their criterion for designing this lens was whether the drawing is beautiful or not. This means they didn't worry too much about the numbers. This ambitious lens does exhibit a marked uniqueness, as opposed to other modern lenses that are losing characters in pursuit of excellence. Once a subject is shot wide open, the distinct bokeh emphasizes it. Although the depiction becomes more elegant in smaller apertures, it still carries something unique to this lens. Single-coated or multi-coated? Frankly, there's no major difference. Still, they offer a choice between the two. Looks like they value playfulness. Go single-coated and you can get tasteful colors or shoot against the sun. Or, go multi-coated to get natural colors. Even though they say single-coated, it's still a modern lens and it takes a "proper" picture. Either way (of coating), this lens will chant in its unique tone.