.jpg "good vs bad bokeh examples")
Round highlights with uniform luminance, smooth edges and no internal pattern (those circles you sometimes see in out of focus areas are interference patterns caused by imperfect lens grinding or minute surface imperfections in moulded plastic elements)Ĥ. No color fringing on highlights, either left-right (lateral) or background-foreground (longitudinal).ģ. Good gaussian defocus in background areas: uniform blur all over, with no double imagingĢ. Remembering that it’s down to personal preferences, most individuals prefer:ġ. It’s why you can shoot through light foliage or fences with a telephoto and not even notice their presence in the final image. This is your typical telephoto shot: beautiful isolation and no hint of foreground or background. Best case: subject is close to the camera, with a distant background long real focal length and fast aperture. This scenario is precisely why compact cameras are incapable of delivering any noticeable blur under most conditions.ī. What will happen? Everything will be in focus. Worst case: subject is far away from the camera and close to the background very short real focal length and moderate aperture.
Distance between subject and background (the further away your background from your subject, the more the blur).Ī. Distance between camera and subject (shorter subject distance means shallower depth of field – remember the percentage explained above).Ĥ. Aperture (wider apertures have shallower depths of field and thus more pronounced blur)ģ. Real focal length (not effective 35mm focal length longer focal lengths have shallower depths of field and thus more pronounced blur)Ģ. The rules of optics also play a big part.
This percentage doesn’t change with the focus distance the difference is the longer the focus distance, the wider the actual, physical range that comes into focus. For a given aperture and focal length, a certain percentage of the focus distance will be in acceptable focus. One important concept to explain up front is depth of field. It’s also why most of the new Nikon f1.4 lens designs have beautiful, non-offensive, smooth bokeh they’re all telecentric designs and optimized for digital sensors. Telecentric lens designs generally have better bokeh than conventional spherical designs this is because you’re less likely to get crossing of rays after and before the nodal point within the lens, causing double images and the like. In general, round diaphragms produce the best bokeh though having said that, the Leica 50/1.4 Summilux-M ASPH has some of the nicest bokeh around, but that has a strange multi-pointed star-shaped diaphragm. The nature of the optical formula and placement and design of the diaphragm, specifically. What factors affect bokeh? Mechanically, the lens design plays a big part. Yet others prefer a uniform wall of gaussian blur foreground-background. There are some who like ‘busy’ bokeh where out of focus areas take on double images, swirls or other patterns some like the pentagons and other shapes on highlights. It’s certainly not quantitative in any way – what constitutes good bokeh and what is bad or ugly bokeh is very much up to the viewer. The closest we can get is ‘the nature/ character of blur’. I believe Mike Johnston was the one who coined/ Anglicised it, though there may be earlier derivations.
The term is a derivative of the Japanese word boke, which doesn’t really have a good translation into English. Possibly one of the most misunderstood, yet most bandied-about terms in the world of photography today – right up there with dynamic range, resolution, A-is-noisier-than-B and other such myths. Plus, things tend to get buried in the depths of time and forgotten…īokeh. This article is one of my first from the archives, brought up, dusted off and refreshed with new images in preparation for the next mini-series on cinematic photography: let’s just say that bokeh matters, and having a little pre-prep can’t hurt.
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