What is the fine-grained topic of the following text: All the question here, is to know if a brand new filter, with nano-multicoating (dedicated for the digital era), is able to make a significant "upgrade" of your old zoom by filtering light significantly better (to avoid this sort of colour cast provided by film lens coatings mounted with high pixel rate sensors). Only return the topic.
The impact of nano-multicoating filters on improving old zoom lenses.