Pentax-DA* 50-135mm F2.8 Review
Derived from a Japanese word, bokeh refers to the quality of the parts of the out of focus parts of an image. There are many factors that can influence bokeh, such as the amount and shape of the aperture blades, optical aberrations, and the overall lens design.
Although bokeh is difficult to judge objectively, there is certain look that is almost universally considered to be pleasing and natural the observer. This quality is commonly known as "good bokeh", and is characterized by dim and soft edges on the out of focus areas, as well as smooth transitions between areas of different color or luminance.
The bokeh quality of the Pentax-DA* 50-135mm F2.8 can be observed in the following images.
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We can observe in the above images that the rendering of bokeh in the Pentax-DA* 50-135mm F2.8 can be classified as neutral, which is very common in modern lenses that are properly corrected for spherical aberrations. The background out-of-focus areas show some hard edges and the luminance/color transitions could be a lot smoother. The highlights are fairly round thanks to the 9 bladed aperture. The foreground out-of-focus areas are rendered very smoothly. While the Pentax-DA* 50-135mm F2.8 is not the best in the bokeh department stopped down, we can conclude that it's rendering of bokeh is still very pleasing wide-open and within the standards of modern lenses overall.
During general use of this lens we found that it doesn't render rocks or grass in a particularly appealing way in out of focus areas. We encourage you to browse member sample photos from this lens so that you can determine whether or not you like the bokeh that this lens produces.