LEICA

Alternative views on the Leica world by Erwin Puts

Leica Elmarit-M 1:2.8/28mm ASPH
Background
One upon a time the Leica M2, equipped with a Summicron 1:2/35mm, was the preferred tool of a whole generation of documentary photographers. The M2 was the wide angle version of the standard M3 and became the daddy of all new M models, including the current Mp and M7. With a small lapse of the imagination, one could even include the M8 into the lineage, at least from an existential viewpoint.



The first Summicron 35mm had an optical cell with eight elements, whereas the latest versions had seven elements, still derived form the classical Double-Gauss layout.
Both the first and last versions of the classical (pre-aspherical) Summicron 35mm lenses enjoyed great popularity and even have acquired semi-cult status. One may with some reason question the validity of this state, but one has to bow to popular reign in this respect.
The M8 can handle all M lenses, but the capture area of the sensor is smaller than the film gate dimensions for the 35mm film format. The capture area of the film has a size of measured 23.85 x 35.6 mm and the M8 has a size of 18 x 27mm, somewhat larger than the classical half-frame dimensions of 18 x 24mm. Historians will remember the Leica pre-war versions with the half-frame gate to allow 72 pictures. The M8 with suitable memory cards will hold more than 200 pictures in Raw format.
The smaller size of the capture area does of course not alter the (optical) focal length of the lens (or more correct the magnification ratio of the lens). But the smaller size does alter the capture angle (viewing angle) of the camera/lens combination. This reduction has become know as the crop-factor, which in the case of the M8 is 1.33. The 35mm film negative has a diameter of 43.2mm or a radius of 21.6mm. This value you will find on all MTF graphs on the horizontal axis. For the CCD sensor in the M8 this diameter is 32.5m or a radius of 16.25mm. A quick check shows that 21.6/1.33 is indeed 16.25mm.
When studying the Leica graphs one should this reduction into account, when one wishes to analyse the image characteristics of the lens related to its use on the M8 body.
A photographer who wishes to take pictures in the great Leica tradition and wants to use a 35mm perspective on the M8 needs a lens with a focal length of 26.3mm. This focal length is exactly between two available Leica lenses, the 24mm and the 28mm! Leica has opted for the 28mm as it is easier to keep the size to small dimensions. This was the double target for the designers: a very compact lens in the tradition of the classical 35mm lens and an improved image quality, at least as good as the current Summicron-M 1:2/28mm ASPH.
Ergonomics
The new Elmarit is indeed very compact, on first inspection it even seems too small. The rings for the aperture setting and the focusing are very close together and it is easy to move both rings when you use the one-finger approach. The classical Summicron 2/35mm (latest version) had dimensions of (length/diameter) 26mm x 52mm. The new Elmarit has dimensions of 30mm x 52mm. The optical cell of the Elmarit is larger with 8 elements in 6 groups. Weight is identical with 150 grams for both designs.
The Elmarit-M 1:2.8/28mm has dimensions of 41.4 x 53mm and a weight of 260 grams. Here too we find 8 elements in 7 groups.
The lens handles with classical smooth precision and even the aperture click stops are above comment: the clicks are at the same time smooth and precise.
With some experience one can cultivate the one finger handling at set/change distance and aperture (in AE mode on the M7/8) with one movement and this approach makes for fast and secure handling in situations where you want/need to change both settings (depth of field accommodation related to the object distance in moving situations). The only small complaint might be that the compactness of the lens leaves little place for a secure fingergrip when (dis)mounting the lens on the camera body.
An anecdote that I wish to share is this: a had the lens for testing during the month of May of this year and used it exclusively on a holiday trip to Vienna. When visiting the beautiful monastery of Melk, I bumped into a delegation of the LHSA people who had planned a trip to the Nikon assembly in Vienna. No partisan divisions among sensible persons! The group was headed by Tom and Tuulikki Abrahamsson. But I could not show the lens to them, even if I knew they would die to handle this one. But I had to use my cloaking device to let the 28mm disappear.
The Elmarit-M 2.8/28mm ASPH. is a very pleasant lens to use on the M8 but is also a very good companion to the film-based Leica cameras. Here is offers the normal 28mm field of view, with compact size, exquisite handling and excellent imagery. The mechanical design uses new mechanical components to reduce assembly time and thus cost.
Optical matters.
The optical cell is clearly derived form the Summicron 28mm design. The after-aperture group is almost identical with a simpler one-element fourth lens group. The pre-aperture group is also closely related to the Summicron with the exception of the shape of the first surface of the front element that now has positive curvature
From a user viewpoint the major improvement of the lens is the lack of distortion. This may be one of the first 28mm lenses for RF cameras that shows no distortion at all. The Zeiss Biogon-ZM 28mm has more distortion (it has 1%, where the Leica shows less than 0.5%). The Zeiss Biogon 28mm for the G-mount has the distinction of being first, as far as my knowledge goes.
But the reduction of distortion to zero and an excellent flatness of field does imply that other aberrations cannot be corrected at the same time to the same level. Wide open (2.8) the lens does not show the crispness of the 2/28mm (at 2.8) or the previous 2.8/28mm wide open. Flare reduction is now outstandingly good and close up performance allows high resolution images from corner to corner. All test comments are based on the 28mm angle of view as the testing was done on film. At the infinity setting one can detect a visible reduction in corner resolution that is gone when stopping down to 5.6. You need to find a subject that offers such small detail that this reduction can be seen. At 3 meters distance (100 times focal length) the lens has excellent overall contrast and the micro-contrast is of a high order, at least till an image height of 15mm, beyond which one sees a gradual softening of detail and at the extreme corners the finest detail is not captured, compared to what can be seen at smaller apertures. But if this level of detail is required, one will stop down a bit.
At 70 cm and wide open the definition of very fine detail is quite good, but lacks some bite. But the corner to corner coverage is excellent.
The shape of the sharp-unsharp gradient is quite smooth and unsharpness blur in fore- and background is visually quite pleasing.
Overall the fingerprint of this lens wide open and at smaller apertures leans a bit in the direction of the Zeiss philosophy of lenses: reduction of flare and distortion is of more importance than striving for the maximum contrast wide open. If you need that high contrast performance wide open, Leica offers the Summicron 2/28mm ASPH.
The MTF graphs show you the idea. Do not pay too much attention to small differences in the quantity and shape of the graph. They will not translate into visible photographic differences.
Verdict
The wide open imagery is very balanced indeed: a combination of smooth gradation at small areas, clean definition of fine detail, good overall contrast, flare suppression that allows the recording of small specular highlights and accurate colour reproduction. You can exploit the wide angle from corner to corner without any reservation. Stopping down to medium apertures (5.6 to 11) allows the full optical potential of this lens to be unleashed. If you are not obsessively critical about detail definition, the choice of aperture is just a matter of composition. It should be noted here that pictures are mainly made between one's ears and not on the optical bench. It is nice to know what the limits of performance are, but one should not indulge in line counting too much.
If we put this design in an historical perspective, we see that current small format lenses, at least from companies like Leica and Zeiss operate at the limit of useful contrast and detail definition. It now makes sense to shift the balance to niceties like reduction of flare, distortion and curvature of field without degrading the overall definition of the lens. Zeiss and Leica do this balancing act with some different weighting of characteristics. Leica puts a heavy weight on compactness and has to go quite deep optical prowess to balance compactness with high performance. And now even price is going into the performance equation.