“If I was being nit-picking I would rate this lens just acceptable for performance (at the price) and very good for value.
Performance wise the lens is vari-focal rather than zoom, meaning that the focus setting affects the angle of view and vice-versa. This makes it a little fiddly to set up. The optical quality is fair at best in the visible spectrum (again, forthe price). It vignettes at certain focus / zoom combinations. Distortion, field curvature and other optical defects are there for those who care to look, but would you buy this lens if cost was not the influencer - of course not.
Infrared performance is suprisingly good (it is marked IR), with little of the internal reflections that plague some optics.
It's a great lens to use for deciding what focal length you need for the HQ camera, setting up a system in the field or just being able to view a subject over a range of angles.
I have paid much more for a lens cap than the cost of this unit, so it's a great choice if cost is the prime factor or operating conditions make the lens expendable.”
