LENS PERFORMANCE

Some key stand out areas are the Planar’s micro-contrast, its depth of field (DOF) and overall flexibility. In the case of the 100mm Planar the micro-contrast results in better gradients and more detailed textures. Compared to Canon L lenses such as the EF 135mm L F2 and EF 85mm L F1.2 (Mark I and II), the 100mm Planar produces subtler gradients and shows more detail. Where the Canon lenses tend to rush to deep blacks, the 100mm Planar holds more mid-tones and captures more detail in the shadows. In general the Planar has a gentler roll-off.

Another key difference between the 100mm Planar and its Canon counterparts is DOF. The 100mm Planar has proven to have a thinner DOF than the Canon 135mm L F2 when shot at equal apertures. Test shots were taken at the same distance and at the same aperture. According to the DOF tables the 100mm Planar should have more DOF; however, it proved to have 1 to 2 stops less DOF than the Canon 135L.

Keep in mind that DOF is not a standardized metric. A Leica 100mm F2.8 Elmarit-R Macro APO, a Contax 100mm F2 Planar, a Canon EF 100mm F2, etc., will all have a different DOF at F4. The resulting DOF is a function of the lens’ design. On-line DOF calculators at various websites ESTIMATE the DOF for given focal length, aperture and distance. This can be misleading because it implies that all 100mm lenses will perform in the same manner, and that is simply not true. There are also dramatic differences in how various lenses in and out of the DOF.

The 100mm Planar’s shallow DOF makes for wonderful outdoor portraits - even at F5.6 there is terrific separation between the subject and the background. The 100mm Planar shots often have a very 3D feel to them. In contrast I do not like the 100mm for product shots because it lacks the needed DOF. Sharpness and resolution peak around F5.6 and seldom does F5.6 have enough DOF for a product shot.

The 100mm Planar performs equally well whether shooting close-up portraits or landscapes at infinity. The micro contrast plays its role which results in deep, rich textures. The added texture in leaves and foliage have the illusion of extra resolution. Overall the Contax 100mm Planar and Canon 135mm L F2.0 have similar resolution, but Zeiss’ superior contrast out-classes the 135L and gives the Planar images more snap. The Zeiss images “pop” and respond very well to post processing in Photoshop.

Other highlights for the Contax 100mm Planar include - essentially zero distortion and a very flat field of focus. Pictures are sharp corner to corner even at F2.0. The 100mm Planar is well known for its smooth bokeh (background blur) with rich, deep saturated colors. In the plane of focus the Planar is nearly free of any CA (color fringing). When shooting wide open there may be some slight CA with a light subject against a dark background or visa-versa. Compared to my experiences with the Canon 85L Mark I and Mark II, the 100mm’s CA is much less. Lastly, the 100mm exhibits subtle light fall off in the corners on full-frame when shooting wide open. In my opinion the fall-off combines beautifully with Planar’s F2 DOF rendering. Many times I add fall-off as part of the editing process, so the Planar’s natural fall off works for me.

I prefer the 100mm Planar as a natural light lens. With a flash or strobes it loses some of its magic. I often shoot with fill-flash (a Canon 430EX on a Canon 1Ds Mark III) when traveling. Back home in front of the computer, the shots taken with a fill flash have a better exposure, but look flatter. The pictures without a fill-flash have more character. When using a fill flash I prefer to sheet with -1 to -2 FEC to guard against the flash overwhelming the natural light. If I were buying a Contax 100mm F2 Planar and planned to use it just indoor for studio portraits and such, in that case I prefer the Canon 85mm L F1.2 or Canon 135mm L F2. Both of Canon L’s respond very nicely under studio strobes. There may also be some advantages in using a Canon EF lens when it comes to ETTL-II.

GETTING THAT 3D LOOK

One of the most common aspects of a 3D effect is typically a narrow DOF to isolate the subject from background - the foreground separates itself from background. The Canon 85mm L F1.2 (Mark I & II) and the Canon 135mm L F2 both do this very well, but the images seldom look 3D. In a recent conversation with Son Min Pham I asked his opinion why the Contax 100mm F2 Planar achieves the 3D look so often. Son said the there are two key lens characteristics needed excellent micro contrast and excellent chromatic aberration (CA) control.

Micro contrast is the subtle tonality apparent in gradients. It is these nuances in the shading which create richness and depth in the color tones. These shadings give objects a roundness and sense of depth. What Son added (which I never thought about before) is that the micro contrast must be excellent across the entire frame. Some lenses like the Canon 135mm L F2 have excellent micro contrast in then center region, but not at the edges. On a tightly cropped portrait, the 135L will have a nice look, but on broader compositions, it will not maintain the “pop” across the frame.

The second characteristic is excellent CA control. Any fringing around the outline of subject diminishes the edge sharpness. The loss of sharpness around the edge reduces the perceived separation from the background, thus the 3D effect is lessened  - or simply lost. The Canon 85mm L F1.2 is notorious for its CA at the wider apertures, the CA compromises the Canon 85mm L’s 3D abilities. Also, the Canon 85mm L F1.2 does not match the Contax 100mm Planar’s micro contrast levels.