Pentax-DA* 50-135mm F2.8 Review
Flare refers to unwanted light in an image caused by scattering and reflections within the lens's optics. There are many types of flare and most, if not all lenses are prone to flare. Flare can be a desired trait and can be used as an artistic element, but for most cases, it degrades the quality of the image by reducing contrast and adding unwanted elements to the composition.
Most modern lenses use some form of anti-reflective coating (Pentax calls theirs SMC, or Super Multi Coating) in some elements in an attempt to minimize flare, although flare cannot be eliminated entirely in a multi-element lens. The lens hood should be used in order to prevent stray light from being seen by the lens.
In this test, we attempt to induce flare with the Pentax-DA* 50-135mm F2.8 by taking images with the sun just out of frame. The following is an example of one of such images, without using the provided lens hood:
As can be observed in the above image, the Pentax-DA* 50-135mm F2.8 is particularly resistant to veiling flare, although there is significant ghosting. Next, we attempt to decrease ghosting by utilizing the provided lens hood:
As expected, the amount of ghosting has been decreased and there are no evident signs of veiling flare.
In regards to flare resistance, the Pentax-DA* 50-135mm F2.8 performs very well, even without the hood attached. In this test, we attempted to intentionally cause flare; in a real-life scenario, the photographer should use composition to avoid flare.