Wickedly cool, that is.
What is it, and what is it for ? Easy, it’s a focal reducer. Say again ? Lemme explain (for those of you who need it, I bet 90% of my reader base know that already, but humor me anyway). Serious digital camera bodies are known as “DSLR” which stands for digital single lens reflex. The digital sensor is smaller (for cost purposes) than a real, film 24x36mm sensor. Because it is slightly smaller the field of view is actually tighter compared to a film camera, we call it a “crop” factor (because it shows only a crop of what the equivalent frame would show in film world). This means when you use a traditional lens designed for film cameras, you must multiply its focal length a bit, generally by 1.5 (1.6 for Canon models). A 50mm “normal” film lens becomes a 75mm “equivalent” lens when used on an APS-C sensor (the one that lives in a huge majority of DSLRs). Yes, some DSLRs sport a real, true 24x36mm sensor, it’s called “full frame” (FF in short) and it’s way more expensive than APS-C size chips. The cameras having them are also generally bigger and heavier. Are you bored yet 😉 ?
Without going into laborious details and hair splitting, and speaking ROUGH equivalence (I’m aware of the micro variations and chose to ignore them), a focal reducer does the exact opposite thing. It “uncrops” your camera by x0.71, meaning on your APS-C equipped body, any given film lens will behave a hair short of like it would on a FF camera. For instance, on my NEX bodies, a 50/1.8 lens becomes a 75mm F:2.7 lens (compared to how it would behave on FF). Now, with this gizmo, the same 50/1.8 lens will still act as a… 53mm F:1.9 lens, so to summarize we may say that the Lens Turbo pretty much *negates* the crop factor of my camera. Wide angle lenses allow wide angle field of view again, and large apertures make for super thin depth of field again. Hurray.
How is this super exciting to ME ? Because I’m a shallow DOF nut. Very thin depth of field involves super specific sharp areas in the subject and blurring everything else to creamy, velvety mush. Aficionados call it “bokeh”. Bokeh is not so much the degree of blur as its *quality* (and the shapes of “secular” highlights, those pretty colorful sports of sheer light that sometimes show in the out of focus areas of a picture). Yum. Not the smoothiest bokeh, but good enough.
The adapter should be here in two days, and I got a Nikon E series 50/1.8 to go with it for starters… Will see how I like the combo, and might decide on more Nikon options later on.