Welcome to Part 1 of a three-part series that lays out the basics of lenses for novices and those who could use a refresher. In this part of the Lens Primer, Larry Becker, of Kelby Media, explores concepts such as aperture, image stabilization (IS) or vibration reduction (VR), and telephoto zoom lenses versus primes.
There are a number of reasons and advantages for choosing to shoot with wider-aperture lenses. Included are the ability to capture sharp, low-light imagery at slower shutter speeds, quicker autofocus and exposure response times—which in turn reduce shutter lag times—and the option to capture your subject in a narrow, selective band of focus.
When defining the term image quality there are several qualifiers that go into the mix. Among them are tonality, contrast, brightness, and dynamic range, which is the degree of detail one can detect in the deepest shadows and brightest highlights. And then you have sharpness, which might be the trickiest to define.