Isaac Newton is perhaps the best known rennaisance scientist today, living between 1642 and 1727. We think of gravity, celestial mechanics, and calculus when we think of him. He certainly did develop the calculus by building upon the ideas of Fermat and Barrow (the person whose chair he took when he went to Cambridge). But he was not alone in developing calculus (see next). And his focus was really one of mechanics - how do bodies move. His focus was always on motion and is reflected in the terminology he chose for calculus - what we call "derivatives", he called "fluxions". And his integrals were simply "inverse fluxions". You can see how "flux" was his focus. He also developed the "dot" notation for calculus - one dot meant a first derivative, two dots a second, and so forth. Today this is used, but only with respect to time derivatives. A general derivative still needs to specify the variable of differentiation and more often than not, time derivatives are done in this more general manner.
As indicated earlier, Newton and his followers argued vehmently with Huygens and his followers over the nature of light. Newton subscribed to a "corpuscular" theory, where he envisioned light as small compact bodies of energy. Huygens focussed on the wave like nature and developed that theory. The diffraction properties of light were so obvious, that Huygens school eventually won out, and the wave theory of light ruled science for the next three centuries.