Pro lenses are delivering so much more sharpness and resolution that older lens designs sometimes start to show flaws that were not apparent with earlier cameras. whenever a new version of a lens is introduced, photographers are shocked by the new price as it is almost always substantially higher than the lens it is replacing. When the new Canon 70-200 f/2.8L IS USM II lens came out, it was priced about $400 more than the lens it was replacing. There is a new Canon 24-70 f/2.8L II just released which is replacing the current lens that was introduced 10 years ago. The price for the new 24-70 is a whopping $900 more than it predecessor!
A German photographer has done an amazing job of analyzing price histories for most Canon lenses and the data shows that the overall average price increase is about 2% per year – less than inflation! These large price increases we see with new lens introductions may seem excessive, but the actual data shows a different story.
You can take a look at his analysis and the conversation it has generated here.