> This is an interesting idea: Could the choice of background *and* distance > from main focus of interest in a photograph be more of an influence than > lens design in the perception of "bad bokeh"?
Tim, In my researches (don't ask), a number of things affect the bokeh: lens design, aperture shape, aperture setting, focusing distance, distance of the background objects from the plane of focus, and the contrast, illumination, and edge texture of the out-of-focus objects. IN GENERAL, the worst-case bokeh is found for most lenses a) at wider apertures, b) closer focusing distances, c) with distant out-of-focus objects d) when those objects are well illuminated and have high contrast. So you can deduce that most lenses to do relatively better when stopped down, focused farther away, with low-contrast and/or darker objects not so far in the background. Also, objects with indeterminate or ragged edges will often appear smoother as long as they're sufficiently o-o-f. You can actually see this effect in pictures where you may have one hard-edged object at the same distance as much softer subject matter, like a bright metal pipe against a muted brick wall or a light-colored streetlight pole against a mass of foliage. In those cases, where the brick or the foliage might be perfectly unobtrusive, the harder shape can show more obvious _ni-sen_ or "double-line" effect. I'm going to do a column on Luminous-Landscape about testing lenses for bokeh, including illustrations that will greatly help clarify the issues, but it's going to be a lot of work to prepare and I don't know when I'm going to be able to get around to it. Hope this helps somewhat in the meantime. --Mike Mike Johnston ________ See my weekly online column about photography at either of these two locations: http://www.luminous-landscape.com/columns/sunday1.shtml http://www.steves-digicams.com/smp/smp_index.html Also, check out my new monthly column in the English _Black & White Photography_ magazine!
