In fact lensrental does something close to that.
I noticed that myself, in Canon land any zoom lens without the red ring and L designation will see its quality dropping over time ( less for L lenses) you can notice it even wihout taking pictures as the zoom tube is loose and there is noticeable wobbling.
Some lenses like a friend Canon EFs 18-200 sold as kit with 50D, I tried last week have became practically non usable
06-28-2018, 08:07 AM
(This post was last modified: 06-28-2018, 08:08 AM by JJ_SO.)
Lensrentals is batchtesting around 10 or more lenses to get reliable MTF of a statistically average lens. They also evaluate sample variation within the batch. In that aspect they deliver more information to single aspects of new lenses.
They also do teardowns and they made lists of quality improvements or also quality loss of manufacturers. I never read such a test like what you were suggesting. The wear of a lens depends of usage (in time), severity of (mis)treatment, was it a new or already damaged second hand lens and also, was it ever at the service point to be checked? Manufacturers or importers like Sigma or Tamron offer a rather long warranty of free service (except parts or labor costs for the damage caused by customer) to check an clean equipment. Also, Nikon has a 3 year warranty in Switzerland - so it's pretty easy to send a lens in after 2 years, suspect a malfunction and get it back checked and cleaned. That's win/win for both sides: manufacturers know their clients and the trouble lenses and bodies could cause and I feel secure to rely on my equipment.
You would not use a car for years without doing some maintenance, a wristwatch of some value eventually gets checked by a watchmaker, a bicycle goes to service - every single item with mechanical parts needs to be maintained. Ignoring that is asking for troubles in future.
But a test how a single lens changed over the years is rather bullshit and meaningless for everybody except the owner. The body ages with it - you'd need to get the whole system checked. If it comes worse to worse, the wear of both adds to bigger troubles, at best all wear equalizes the lack of problems or the AF got faster, because it needed more play fromt he beginning. Just look at some people of your age - some will look much older, others a tad younger, but what does it tell you else than different lifestories cause different outcome?
But if you already know that a certain series is worse (and cheaper, too.... no free lunch), just avoid it.