Nikon 85mm Verses Canon 85mm, F/1.4 or F/1.2, It's About Bokeh
20 Oct 2010
My Bokeh Makes My Photographic Style
Still photography camera lenses come in many sizes, shapes and forms, but the one thing they all have in common, they collect the light that enters their barrel. Those rays of light pass through the optical elements of the lens, or aperture, similar to the pupil of the eye. It's this aperture, or full opening of the lens, that determines the "cone angle" of these bundled rays, or "pencils of light," that eventually strikes the imaging sensor in your digital camera providing you image sharpness and bokeh (the aesthetic quality of the blur). Some say, "It's the bokeh that sets the photographic style of a photographer," though in reality, it's the lens construction that beckons bokeh.
Lens construction causes these pencils of light to strike the digital camera image sensor, where they are collimated by the physical "aperture stop" to provide a sharp focus on the image plane. The smaller the physical stop, or higher aperture value, the more collimated the rays of light become up to the "optimum" aperture value of the lens before diffraction sets in. Collimated light simply means that the rays are more parallel to each other than uncollimated rays. In photographic terms, as the aperture stop is opened toward maxim aperture, the light rays are less collimated, thus sharp focus is only available for the rays at a preset focal length, or focus point, and all other light rays outside this point become blurred with their own unique bokeh signature.
"Bokehâ€”The 'blur' outside the focus point of an image that sets the mood in the photograph and establishes the style of the photographer."
It's the lens optics and the physical aperture stop mechanism that affect sharpness, lens aberrations and bokeh. Think of the aperture stop, sometimes called aperture blades or diaphragms, like the iris of your eye while the lens optics as the curved cover (lens) of the pupil. Eyeglass wearers, like myself, use corrective lenses to fix our physical aberrations caused by improper lens curvature. In photography, we rely on precise optics, so our camera lenses don't need further corrections and optics inside a lens are usually spherical or aspherical, or a combination of both. It's these optics that target the reduction or elimination of various aberrations, the most common, spherical (affects sharpness), coma (think comets, blurring at the edges of light points), chromatic (failure to focus all colors to the same convergence point, distortion), astigmatism (points to blur, affects sharpness), curvature of field (image points bend at the edges, straight lines not rendered straight), and distortion (barrel and pincushion).
Most of the aberrations, except distortion and curvature of field, are reduced and improved upon by simply stopping down your lens and not shooting at maxim apertureâ€”but it's usually the maxim or close to maxim aperture that provides that unique bokeh that some of the great portraitist look for in their image. Herein lies the decision maker when it comes to lenses, is my bokeh better than your bokeh? In fact, some make bokeh their photographic style that sets them apart from their competitors and apparently camera manufacturers are catching on as Nikon recently introduced their "new" Nikkor AF-S 85mm F/1.4 lens as I'm sure they're tired of hearing Canon 85mm F/1.2L USM lens shooters say, "My bokeh is better than your bokeh." Sounds like a lot of bokeh BS right? Not hardly. There are reasons bokehs are different between these lenses, including the lens optics, the aperture stop and maxim aperture.
A great example, often when I'm conducting photography workshops, my attendees are practically salivating over my Canon 85mm F/1.2L USM lens attached to my Canon 5D Mark II, especially the Nikon shooters with their 85mm F/1.4D lenses. Being that I started out shooting Nikon and have always had a love for Nikon, I began to wonder why my photos of the same model, with the same lighting setup and location, were so different from my fellow Nikon shooters at the recent Outer Banks, N.C., photography workshop. Not to mention, I grew up using Nikon F's with Nikkor 85mm and 105mm lenses way before auto-anything, so I asked myself, "Why so different?" In fairness to my Nikon colleagues, I even shot at F/4 and compared my images to one of my photo workshop attendee's Nikon images, there was bookoo difference.
I searched and searched and what I was able to find out, the main difference, besides the obvious maximum aperture values, is that the Canon lenses use an optical element that is aspheric and it appears, as nowhere on the Nikon website could I find it like Canon's website, that Nikon uses spherical optics in their previous 85mm F/1.4D lens and in their recently introduced AF-S Nikkor 85mm F/1.4G lens. Aspheric lenses are not only more expensive than spherical, but aspheric lenses, reduce or eliminate aberrations, normally better than spherical lenses. With today's technology, there is no need to use a magnifying glass to look for minute aberrations, but it's worth noting the difference.
I'm sure there are many reasons Nikon revamped their 85mm lens that was first introduced by Nikon in 1964, but the reviews I've read tend to focus on how the new Nikon G version of their D lens has much better bokehâ€”though I found one review that asked about "ED?" No, not the blue pill type, but something I grew accustomed to in my Nikon days that basically caused me to seek their top lenses, their ED labeling. According to Nikon, if their lenses have ED labeling, it means, "...glass to enable the production of lenses that offer superior sharpness and color correction by minimizing chromatic aberration." In fairness to Nikon, I don't think they've ever made an ED version of the 85mm, though their lens' coatings have changed from NIC, to SIC, to Nano so you'll see a great big "N" on the new 85mm and no ED.
According to Canon, their "L" stands for, "... L-Series lenses incorporate specialized optical materials such as synthetic fluorite, Super UD and UD glass, and large-aperture high-precision aspherical lenses. Only lenses that perform to the highest photographic standards are allowed to bear the designation L." These are Canon's best and most rugged lenses, though most photographers make fun of the Canon "L" as a symbol for Love or Luxury. I wonder what they'll say about "N" for the new Nikon 85mm? I can hear the diehards arguing now, Naughty, Nice, Nada, but in really it stands for Nano.
I also noticed, in actual lens construction, that Nikon added one lens element and one group in the optics of the new G version verses the now out of production 85mm F/1.4D lens that has nine elements in eight groups. That's 10 elements and nine groups for the 85mm F/1.4G lens, whereas the Canon 85mm F/1.2L lens has eight lens elements in seven groups. I will always have a place in my heart for Nikon, but I prefer to shoot through the least amount of glass as possible to avoid aberration potential from each optical element.
Putting all the marketing hoopla and tech specs found on Nikon's and Canon's website aside, obviously Nikon felt bookoo pressure of the Canon 85mm lens as the Nikkor 85mm F/1.4G lens was just released this September. One interesting note, the new "G" lens has Nikon's Nano Crystal Coat, an antireflective coating not found on the old D lenses, so that's a plus and I encourage the old Nikon D-lens owners to use Ebay and upgrade to the new G version of this longtime, portrait photographer's workhorse lens. Canon shooters, I don't recommend selling your 85mm F/1.2L USM lens on Ebay, instead sell your old Canon 70-200mm F/2.8L USM IS and buy version two of this staple lens.
Now getting past the optics, one thing currently both Nikon and Canon 85mm lenses have in common is that they use a nine-blade, rounded aperture stop, which in reality makes bokeh more pleasing. It's the bokeh, in my opinion, that separates the Nikon and Canon 85mm lenses because the bokeh is different at F/1.2 verses F/1.4. I hear too many photographers argue over both lenses with common statement, "With today's high and almost noise-free ISO's, who needs F/1.2?" While it's true that the difference in light striking the imaging sensor between F/1.2 and F/1.4 is not that critical in most lighting situations with such high ISO's, it's the bokeh that really makes the difference in the final image when it comes to photographic style, especially when the lenses are used at their maxim apertures. Both lenses provide their own unique bokeh and that's what my Nikon buddies pointed out to me at the Outer Banks photography workshop, the bokeh of the Canon F/1.2 lens is a painterly styleâ€”think the iconic photographer, Robert Farber's style.
So whether you're a Nikon or Canon photographer by heart, as I share my passion for both brands, it's ultimately what you're trying to achieve in your style and final photographs and each lens has it's unique qualities, some more favorable to your own personal style than othersâ€”so you'll have to decide, is the Canon bokeh better than the Nikon bokeh? Food for thought, corrective eyeglasses are aspheric. I personally made the switch to Canon because I'm working on a book called "Wide Aperture" and Canon's 85mm F/1.2L USM lens is my lens of choice for a big part of that body of work, but don't be surprised if you find some Nikon images in that book too, though you'll see the difference in the bokeh with my style of shooting.