Were I into pop-psychology, I might assert that Renoir experienced a "mid-life crisis" in 1883 when he was in his early 40s. He began to doubt his Impressionist painting style and experimented with a more delineated, harder-edge approach inspired by his admiration of Ingres (who Picasso also claimed to admire). This is noted in his Wikipedia entry and elsewhere on the Internet. It is also discussed in this book by Anne Distel, a Musée d'Orsay curator.
Renoir's wanderings in a not-quite-Impressionist wilderness lasted roughly five years (1883-88). He then picked up where he had left off stylistically.
But not entirely. From time to time he continued to make paintings featuring more sharply defined subjects. And not just commissioned portraits; the final painting below was done for his own purposes in 1896.
To set the scene are the two paintings above, made not long before he modified his style.
As this link notes, Renoir began "The Umbrellas" around 1880-81 and then reworked and completed it about 1885-86. It notes that the right side seems to have been painted first and the left part later. So it is a stylistic hybrid that Renoir was hesitant to sell for several years.