Instruct: Classify the given review as either positive or negative.
Query: Not as good as expected

First off, let me say this is a great lens. It is clear, well built, and delivers great pictures in most circumstances. My disappointment comes mainly in regards to the f/4.0 limitations of this otherwise excellent lens.I do a lot of photography in marginal lighting. The fact that this lens is a 4.0 means that often that marginal light is just not enough. Add in the polarizing filter I often have a attached for landscape work, and you understand what sort of problems this can be. The image stabilization helps, but is still no substitute for a decent apperture.Buld quality is excellent. Distortion, clarity, and all the other normal attributes of a L series lense are right where they need to be, but the lack of low light performance seriously detracts from what is otherwise a superior product.