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Lens Diaphragm Bokeh
With the right amount of defocus and bright points of light, the lens diaphragm can be imaged to show its shape clearly.
These pentagonal highlights do not appeal to me, a lens diaphragm with 9 or more blades generates a much more circular and therefore appealing effect.
Some lenses have as many as 14 blades, which makes for a truly lovely effect on such highlights— think lenses for cinema, and pay attention to the next movie you watch where there are bright out-of-focus spots in the background.
Such highlights can show up at undesirable times and make their presence felt. I consider 9 blades the minimum for good bokeh, though an 8-bladed aperture with rounded blades is good as well.
Examples
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- Depth of field and how to bypass depth of field limitations via focus stacking.
- Optical aberrations: what they are, what they look like, and what to do about them.
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- Optical aberrations: what they are, what they look like, and what to do about them.
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Intrigued? See Focusing Zeiss DSLR Lenses For Peak Performance, PART ONE: The Challenges, or (one topic of many) field curvature.
LEICA M (Typ 240) + Summarit-M 1:2.4/75 @ 75mm
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