What Tamron got right with this lens…
Small and lightweight.
Class-leading zoom range. Appears to do the jobs of several kit lenses at once, and do them well.
Zoom and focus rings are in a familiar place for higher tier lens users, allowing you to focus manually and stabilise the lens at the same time.
Supplied with a lens hood, unlike Canon’s current 18-200mm.
Short travel from minimum focal distance to infinity.
Zoom lock at 18mm for safe transportation.
Surprisingly sharp considering the range.
Focus is very quick and quiet.
Vibration Control works very well, and makes the lens much more usable at the long end.
Bokeh at 130-190mm is good, with little distortion.
Room for improvement…
A lens pouch would be nice.
I’d like to see the push/ pull manual focus override of the 90mm macro on the next version of this lens.
Without the above feature, I think the AF on/ off switch should be in the position of the VC switch, and vice versa.
A redesign of the zoom-lock switch, to allow for locking at several focal lengths.
Based on other’s experience of the lens, I can’t recommend the use of protective filters with the 18-270, due to vignetting (particularly at the widest extreme of the lens). This seems to be compounded if you also use the supplied lens hood. However, using the hood on its own seems to be fine, and protects the lens adequately.