You really can’t overstate the role the term "bokeh" played. When a lens manufacturer brought a new product to market, they could describe how the iris system would make for a "pleasing bokeh" instead of a "pleasing shallow depth-of-field look where highlights have a smooth shape." Just like that, a trend took hold on the demand side (photographers and filmmakers) and the supply side (manufacturers).
|The Leica Noctilux lenses are the gold standard for fast primes. With ƒ/0.95 maximum apertures, they allow you to shoot in low light at moderate apertures and create stunning bokeh. The Leica Noctilux-M 50mm ƒ/0.95 ASPH also costs about $10,000. Recently, the Chinese company Zhongyi Optics has come out with the Mitakon Speedmaster 50mm ƒ/0.95 PRO, which some have said is a Noctilux clone, but priced at a much more approachable $850. Photographers have been using this lens for both still and motion shooting with impressive results. If you want to push the extremes, give the Mitakon a look, www.zyoptics.net.|
Any lens can create bokeh, to some degree. The faster the lens, the more dramatic the potential effect—the more wide open you shoot, the softer the out-of-focus elements become. A pro-caliber prime lens with a maximum aperture of ƒ/1.8 or ƒ/1.4 has much more bokeh potential than an all-in-one zoom with an ƒ/3.5-5.6 variable aperture.
Everything is a trade-off, of course, and lenses are seldom at their best when used wide open so, in addition to bokeh, you’re likely to see some vignetting, color fringing and other imperfections, particularly at the edges of the frame. That’s not necessarily a big deal as long as you’re mindful when you compose the image.
In addition to the maximum aperture, the physical nature of the iris itself plays a key role in bokeh. When you look at an image with shallow depth of field, you’ll actually see the shape of the iris in the soft highlights, especially in light sources. By using a particular number of blades in a particular design, the highlights will show a smooth, round shape or not. Typically, if you’re shooting at the very maximum aperture, you won’t see the iris blades at all, but as mentioned, shooting that aperture usually creates issues.
In addition to shooting for bokeh, there have been software tools to simulate the effect in post. Alien Skin Bokeh was a plug-in that the company now incorporates into its Exposure software. If you’re skilled in Photoshop, there are also techniques you can use to create a very good bokeh effect. Despite these solutions, getting it right in-camera is still best.