Well, Bondo was kind enough to lend me his brand new 100mm ZF macro lens for me to try out on my D3 and F6. I am greatly indebted to him for this kindness. It was uncommonly generous, and I am very grateful that he allowed me to try out this superb lens. Before I proceed, I want to specifically note that these are my results, within my own system and workflow. I do not want to be regarded as the authority on any differences there might be between these two lenses. These are simply the differences as I see them in my experience.
I should also note that both these lenses are spectacularly good, but they are different. The Leica is a slower lens, apochromatically corrected, and of course over 4000 dollars new. Used prices run from about 1300 for a user 3-cam version to 2000+ for a ROM version in mint condition. The Zeiss lens is approximately 1580 dollars new, and includes a hood. It is a stop faster, but does not have apochromatic correction. Build quality on both these lenses is excellent. I would have to give the edge to the Leica based on the superior feel of the aperture ring, slightly smoother focus and built in hood. Both are extremely rigid even when at full extension -- there is no play in the lens body of either lens, which is a good sign. Both have nice, largely circular irises at all apertures. The Leica has 7 blades, and the Zeiss 8. My only criticism of the Zeiss build is that its focus and aperture turn the wrong way . It mounts backwards too. Oddly, all Nikon mount lenses seem to share this defect. The Leica is thinner (E60 versus E67), slightly longer, and about 100g heavier. Despite these differences, these lenses are similar in application and in use. They are both 100mm manual focus macro lenses optimized for very high optical performance at all distances. Used correctly, neither of these lenses will let a photographer down -- they are cream of the crop. The question is which is creamier? In short, for me the Elmarit, but reasonable people could choose the Zeiss as well.
I compared these lenses on two different systems. I did a digital comparison using the D3 and DMR, and a film comparison using an R6 and an F6 on Rollei 25 Pan film. I scanned the film results as 6300 dpi on an Imacon 646. One interesting corollary of the test was how the film and digital results compared. In short, both the DMR and the D3 offered significantly greater clarity over even ISO 25 film developed in a fine grain developer (xtol). In any case, the results of the film test closely mirrored the results of the digital test, so I am not going to bother posting the film results.
Sharpness: These two lenses are remarkably close, at least when focused with similar image areas. In the test where I photographed the wall, both lenses held superb resolution from the center all the way across the frame, even wide open. The Leica had a miniscule edge at f/2.8, particularly in the edges, but even this is debatable. When I tested at “infinity”, just the lenses at infinity shooting across the East River, the Leica clearly won, but this is entirely because the DMR is a 1.37 crop, so a 137mm lens rather than the 100mm lens on the D3.
Vignetting: This is an issue. The Leica doesn’t have any; the Zeiss does. The vignetting at f/2 in the Zeiss lens is quite visible, and it remains visible at f/2.8. It disappears by f/4. Luckily, unless you are shooting film, this is easily corrected. Even wide open, while visible, the vignetting is not atrocious.
Chromatic Aberration: In my opinion, the largest problem with the Zeiss lens is its chromatic aberration. In my experience, it shows up readily in images shot at f/2. It will show up as magenta or green, depending on the state of focus of the edge. It seems that in focus areas go magenta, and out of focus areas go green. This is just my general experience. Stopping down to f/2.8 makes it far less apparent, and it is usually gone by f/4. The Leica’s apochromatic correction really helps it here, and I was not able to induce chromatic aberration in any of the shots I took.
Bokeh: Each lens has excellent bokeh, and I don’t see either exhibiting much harshness in their out of focus areas. If I had to give an edge, I would give it to the Zeiss. The Leica has the slightest tendency to give ring bokeh (circles where the edges are brighter than the center), while this is less apparent in the Zeiss. Both look great on this front.
Overall: If I had to choose between the two without regard to price or camera system, I would choose the Leica. I would happily sacrifice the extra stop to not have to worry about chromatic aberration or vignetting. I also prefer the ergonomics of the Leica better -- its slimmer body, larger focus ring, built-in hood and properly turning focus and aperture rings. Users concerned with speed and bokeh can easily choose the Zeiss without reservation -- though it has some vignetting and aberration wide open, it is completely usable at f/2. By f/2.8, it is nearly at the performance of the Leica, and by f/4, they look remarkably similar. Bottom line, choose the one that fits your camera body...you are not going to find better 100mm lenses. Just to throw a monkey wrench in the works, I compared the 105mm f/2 DC nikkor at the same time, and while it was clearly bettered by the Leica and Zeiss, it still performed superbly well. If you need or want autofocus, particularly for portraiture, this lens cannot be ignored. In my last test, the AF seemed to be malfunctioning. I performed this test with live view and contrast detect AF, and the lens did much better. Though it is still behind the Zeiss and Leica, it is not very far behind at all. I have not had the chance to try the 105mm f/2.8 VR lens, though I am sure this would also compare well.
On to the images.
At the famous wall. Here I was unable to perfectly match the image sizes of the D3 and the DMR. Because the DMR is a 1.37 crop, I had to move back to get the same scene in the viewfinder, but I wound up literally hitting the wall. The Leica image is still slightly tighter. This gives it a slight advantage here, though it is at a slight disadvantage in terms of megapixels, so I think it more or less cancels out.
Please note, it may be easier to open these images in new tabs or windows in order to compare them side to side more easily.
Leica at f/2.8
And the Zeiss at f/2 (wide open)
Zeiss at f/2.8
Nikon f/2 crop:
Nikon f/2.8 crop
And the Leica crop at left, f/2.8:
The Nikon crop at left, f/2:
and at f/2.8
I will refrain from posting the f/5.6 crops, as both lenses do so well as to make them identical. The vignetting of the Zeiss disappears.