Leica Elmar-M 3.8/24mm ASPH., part 1 (October 27, 2008)
Introduction
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 desings 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 shouls 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, lless 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.
Left: the design of the Elmarit 24, right the design of the Elmar, note the filter in front of the lens.
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 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 have been presented in a previous article 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.
Let us start with some straightforward analysis. The image quality in the main part of the image circle is represented here below. First the measurements of the Elmar. Note that there is a visible difference between the apertures of 3.8 and 4. Note also that at 5.6 the performance is already a bit below optimum. The range is 3.8 - 4 - 5.6.
The graphs for the Elmarit are very close, but at 2.8 the Elmarit is of course not as well corrected as the Elmar at 3.8. The range is 2.8 - 4 - 5.6.
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).
Below you find the close up performance of the Elmar at 3.8. Slightly better even than the quality at f/4.
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.
IN the next part I will look at the aspects of vignetting, flare and quality at the edges and in the corners. .