LEICA

Alternative views on the Leica world by Erwin Puts

Leica Elmar-M 3.8/24mm ASPH



The new lens series, designed and made made by Leica, is a clever mixture of elements from the classical lens series (exemplified by the Tri-Elmar-M 28-35-50 and the Elmarit -M 2.8/24mm asph.) and the modern designs exemplified by the recent Summarit series. Leica is a traditional company where time honored principles are held in high esteem and even practiced today. If a company should be equated with design excellence, meticulous craftsmanship and metal-based precision engineering, it is Leica. The design principles and manufacturing requirements and processes were and are focused on manual assembly and very careful attention to very tight tolerances. Humans are able to operate at tolerance levels that lie beyond what machines can handle. But humans are also prone to fatigue and individual judgments. The new Leica approach to lens design and manufacture tends to emphasize the practice of close-tolerance manufacture and more automated assembly of parts and groups. When you have to spend less time on checking and adjusting parts or try to match plus/minus tolerances, the process of assembly can be done quicker and with less errors. And assembling groups is always easier than assembling parts.
The Summarit range has been trimmed for easy manufacture and assembly to keep costs down. The for Leica designs moderate apertures and focal lengths have been selected to not frustrate this process.
The new Elmar-M 3.8/24mm is a lens that has its origins in the current thinking within the Leica company and uses best practices form both design approaches.
The basic specs.The Elmar-M 24mm cannot be compared directly with the Elmarit-M 2.8/24mm as there is too big a difference in aperture. The stop difference cannot be ignored when comparing these lenses. It is a quite interesting comparison, but one should always keep in mind the speed of the lenses.

The Elmar is an eight element design and the Elmarit is a seven element design. Both use one aspherical surface and there is no floating group in both designs.

Left: the black and chrome versions of the Elmarit, right the Elmar. The Elmarit black has a weight of 290gr and the chrome version weights 390 gr. The Elmar is almost as heavy with 260 gr for the black anodized version. The weight difference of 30 gr. is the result of a mix of more glass elements, different weight of the glass types used, less glass weight because of the smaller lens elements and the weight of the materials used for the mount. The Elmar mount is redesigned to accept the new screw-in shade, which makes the front diameter less bulky.

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Above: the design of the Elmarit 24,


Below: the design of the Elmar, note the filter in front of the lens.
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The handling
Both lenses handle with the traditional Leica smoothness and solidity. The aperture ring of the Elmar has click stops that are just smoother than the Elmarit where you feel a more definite click movement. The distance ring of the Elmarit and Elmar show no change in resistance from infinity to close distance, but the Elmarit movement is just a bit more solid and feels better.
The lens hood of the Elmar is more effective than that of the Elmarit and has less volume. The filter has a size of 46mm (55mm for the Elmarit).
The full performance and capabilities of the 24mm focal length ask for a film loading camera and then the additional finder is required. It is possible with good expertise to guess the scene framing, but this is only useful when doing snapshots.
The number of blades in the Elmar is higher and the aperture shape is more circular: better for unsharpness rendition.
The performance
Overall both lenses perform superbly good. The Elmarit is a superb lens, given the wide aperture and the angle of view. With seven elements it represents the best of Leica design. The Elmarit lens has more volume and this is indeed needed to accommodate the one stop more speed. The length measurements can be done on any one of three positions: (1) from the front lens ring to the bayonet flange; (2)from the front lens ring to the back of the bayonet ring and (3) from the front lens ring to the mount of the lest element. On these three lengths the Elmarit has a length of 45mm, 52mm and 58mm and the Elmar has 40.7mm, 47.2mm and 53mm. The Elmarit has a diameter of 58mm where the Elmar brings 53mm. The fact that the performance of both lenses at comparable apertures is quite close and for the Elmar a bit better at the edges of the field can be partly explained by these numbers.
The MTF diagrams are available on the Leica website and are not repeated here. A word of warning is not overdue, however. One can do a close comparison of the numerical values of the graphs and assume that small differences in the values will translate into visible differences in practical photography. Sometimes this is true, often it is not.
The overall differences are very small and for all intends and purposes one might state that both lenses perform equally well, with the definition wide open of the Elmarit hardly lagging compared to the optimum values.
The close up performance of both lenses at f/4 is also equally good, with a slight advantage for the Elmar (top) compared with the Elmarit (below).
The primary characteristic of the Elmarit is its outstandingly good performance at all apertures, with its peak at 5.6. The remarkable conclusion for the Elmar is the fact that the best aperture is wide open. Stopping down is only required for extended depth of field. If not necessary, you should leave the aperture wide open. Here the lens has the best overall definition.

The analysis of the wide-angle lenses requires a film-loading M-camera. That is for the moment the only way to test the capabilities of the lens at its full angle of view. The published MTF graphs and additional info do help in getting insight into the inherent performance of the lens. You need some experience to relate the performance parameters to actual imagery. There is also the danger that too much attention is given to small differences in the published data. For a given lens the contrast at 40 lp/mm could be 45% and for another lens it could be 53%. The difference in measured value is hardly visible in practical use.

For the current tests I employed ISO100 BW films from Ilford and Kodak (Delta100 and T-Max100), developed in CG-512. This developer gives excellent sharpness and very fine grain. The negatives need to be scanned with my Nikon Coolscan 5000 and the Nikon is notorious for exaggerating the grain clumps in the negative. The finer the grain, the better is the quality of the scan.

The angle of view of the Elmarit is visibly wider than that of the Elmar 24mm. The magnification of the Elmar is somewhat greater as will be visible in the comparison pictures below. Strictly speaking, the Elmar is closer to 25mm and if you would be very rigorous, a direct comparison has to be done with some reservation.

Below left the edge of the Elmar; Below that: the edge of the Elmarit.

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Vignetting
Both lenses have the same amount of light fall off: close to two stops in the extreme corners. This does seem to be a large amount. Remember, if you will, the fact that a negative is developed to a CI value of 0.55 or 0.65 for most enlargers. A full stop difference in the scene is rendered on the negative with a 50% difference in density, or effectively one stop. Depending on the brightness distribution of the scene, the fall off in density is more or less visible. Film is in this respect more accommodating than the solid state sensor. The visibility of vignetting depends in addition on the over- or underexposure of the scene. The distance of the camera to the scene is another factor. The closer you are, the more visible the fall off.
Based on the graphs, the Elmarit at 2.8 is almost as good as the Elmar at 3.8, but at 5.6 both are equal. In practical use, I could not detect occurrences of vignetting that became bothersome. In most pictures made wide open, the vignetting is negligible.

Definition
This is the main characteristic of a photographic lens. According to the MTF graphs, we may expect that the edge and corner performance of the Elmarit is slightly less good than the Elmar. Do we recognize this in actual photographs?
I took pictures of a building that exhibits the range of textures from very fine to major outlines. Really fine detail can be seen in the textural details of the stones of the wall.
The Elmarit 24mm hardly improves on stopping down in definition when we look at the large central portion of the negative. Photographs taken at 2.8, 4, 5.6 and 8 show a visible improvement in contrast of very small details. At normal enlargements up to A4 this difference might not be discernible.

At the extreme corners we do indeed see a quite visible softness wide open, compared with the same picture at 1:5.6. Note that fine detail is still resolved at 1: 2.8, but contrast is quite low. At 1:5.6 very fine detail becomes visible, that is absent at full aperture.

The Elmar 24mm offers identical quality in the central portion of the negative. At 1:3.8 the picture is not different from the Elmarit picture at 1:4.

At the extreme corners the Elmar wide open (1:3.8) is as good as at 1:5.6 (bar a faint increase in contrast and crispness).
The claim that the Elmar presents a very homogeneous quality over the whole negative area and at all apertures has been borne out.
A comparison of the performance of the Elmarit and Elmar at 1:4 and at the edge of the negative shows a very small difference in better crispness and contrast for the Elmar, but not very impressive. But there is a small improvement!

Flare
A comparison at 1:4 for both lenses shows that flare is well suppressed. There are no secondary reflections to speak of and subject detail is preserved even in areas of a strong light source. In the shadow areas the Elmarit has a small edge where contrast is concerned. Given the large front lens the propensity to flare is very low.

Bo-ke(h)
A dangerous subject! There are so many variables to take account of (distance of main subject to background, distance of camera to subject, aperture used, type and direction of light and so on). In the pictures used here, I have looked at the unsharpness representation of branches of trees and foliage. Both lenses (at 1:4) show almost identical qualities here. The background is smoothly unsharp und does not show any harsh or double outlines.

Conclusion
The Elmar-M 1:3.8/24mm ASPH. represents outstanding value for money and shows a very high level of performance. There is hardly a discipline where the Elmar does not bring top results. The size is extremely comfortable for snapshot use. The demanding and discerning user gets all the performance that can be required for exhibition type pictures of a very high calibre.
The Elmarit-M 1:2.8/24mm ASPH. does deliver the same high quality and offers a full stop advantage in speed. The size is comparatively speaking quite large, and at the edges of the frame the performance is slightly lower than that offered by the Elmar at comparable apertures.
The wide angle of view of a 24mm lens needs mental adjustments by the user to find and exploit pleasing compositions. At closer ranges and stopped down to get sufficient depth of field the Elmar is a very fine lens for powerful snapshots of live events.
The Elmarit can impress with a mechanical quality of the highest order, especially in the silver chrome version. The Elmar has been manufactured with the new Leica standards and equipment. This topic will be discussed later.