How to tell if a lens is damaged after fall
I was recently at a anniversary dinner and had an unfortunate accident involving a collapsible table, a 4 year old and my Tamron 70-200 F2.8. While changing lenses i had my Tamron on the table and a 4 year old bumped the table as he ran passed. The table collapsed and my lens went sliding off. Thankfully it had the lens hood on and a UV filter and was only a 3 foot drop onto carpet. Upon inspecting the lens its seemed fine with no cracks or marks. The front and rear elements are fine and the lens still focuses fine.
However while using it yesterday i noticed that my images were not as sharp as i seem to recall when using this lens. The images seem fine at first glance but when inspected at 100% they seem a tad soft. I did some test and on high contrast subjects such as text and labels and its seems fine. But on less contrast subjects with finer detail such as cat fur it seems a tad soft with not all the fur been sharp (mainly edges) in a random particular area of a image.
It looks like a element in the zooming group of the lens may be 1mm (if that) out of alignment to the others with a tiny gap on one side of the lens group.
As i am a photographer not a lens tester or repairer how can i tell if my lens is indeed damaged because of the fall and if it is worth taking in for repair. If it is a lens group that is slightly miss aligned with the others will this affect IQ and is it fixable?