Usually when new smartphones appear in close succession their cameras are well compared on tech sites or magazines, for example like here the S7 and the OnePlus3.
But are there such tests which compare newer models with older ones. Surely, most are interested to choose from what currently is on the market, but sometimes people (like me now) want to know whats gained if they buy a new device. So are there comparison tests like the above that span "smartphone generations", for example comparing a Nexus 4 vs the new Samsung S7 or something like that? Surely most of the time the new devices score higher, but it would be still interesting how much better the results are, and if its worth.