LEICA

Alternative views on the Leica world by Erwin Puts

  • Summicron-R 1:1.4/50mm

  • Vario-Elmarit-R 1:2.8-4.5/28-90mm ASPH

  • Summicron-R 1:2/180 APO and Elmarit-R 1:2.8/180 

  • Vario-Elmar-R 1:3.5-4/21-35mm ASPH

  • Super-Elmarit-R 1:2.8/15mm ASPH.

Introduction
In the early fifties and sixties the ultimate object of desire for any 35mm photographer, who liked or needed to practice the art of the artless snapshot (HCB-style) was a standard lens with an aperture of 1,4. Any additional photon that could be captured on emulsion while shooting in “available darkness” was most welcome. The slender depth of field at that large aperture added quite often impact and drama to the image. The need for such a large aperture became imperative after the candid pictures of Erich Salomon of Ermanox-fame. The 35mm worker got what he demanded in the early fifties as coated 1,5/50 designs from Zeiss and Leitz became available. These lenses indeed did capture some of the additional photons. But the photons on their way through the many glass elements wandered around (ab errare). Aberrations abounded and the image quality, to be polite, was just acceptable. The Leitz Summilux 1,4/50, introduced in 1959 for the M series camera was the first to offer a higher level of image quality. A redesign , offering very good quality, was introduced in 1962 and is still in production.
The Leicaflex user had to wait till 1970 before she could capture scarce photons. Again a redesign in 1978 improved the quality. In the meantime the emulsion technology made some quantum leaps in speed/granularity relationship and the ubiquitous electronic flash lessened the need for high speed optics. Some even predicted the demise of this type of lens. More so as the 50mm fixed focus lens is nowadays often being replaced by a ‘standard zoom’ of 28/35 to 70/85 focal length.
Optical design principles.
The design of a 50mm high speed lens is quite a challenge. Its sibling, the 2/50mm, offers image quality of the highest caliber (at least in the Leica stable). And the optical aberrations to correct are quite stubborn. Most reviewers of high speed lenses even today will tell you that a 1,4 design is a compromise. What then is the optical problem? Any lens produces a circular image area within which the 24x36mm format has to fit. This circular area can be divided in three parts, the center, the zonal area and the far out zones. The center (or the paraxial zone or Gaussian zone) is quite easy to compute. The zonal areas are more difficult to correct.
Optical aberrations have the habit to grow disproportionately if the aperture and/or the field-angle become wider. Many aberrations grow with the square root or the cubic root in relation to the aperture diameter or even more. OK you would say, lets settle for a bit less image quality in the corners. The snag however is this: the zonal aberrations have a strong influence on the performance in the center. Moreover: when stopping down the effect on some aberrations is not reduced. The combined result of all aberrations is always a reduction in contrast: a softening of small details and a low overall contrast. The lens designer’s plight however is not over if he succeeds in reconciling all these conflicting demands. Aberrations can be classified as third order, fifth order and seventh order aberrations and so on until the n-th order. (I will explain in a separate post why they are so designated).
Third order aberrations are large and suppress all other aberrations in the series. If a designer can tame these third order errors, he will be unpleasantly presented with the next in line. Balancing third order aberrations require often a change in focus position. The well known statement that you can compute a lens for high contrast or high resolution ultimately boils down to this kind of balancing. Fifth order aberrations are mathematically quite challenging.
The high quality of Leica lenses is based upon an excellent grip on this group of aberrations. As usual a balancing of conflicting demands and fine-tuning of parameters is needed to compute a lens to this very high level of correction.
But choices are inevitable.
If the designer has done her best (actually some of Leicas best optical designers are female) she would be lost in space if the manufacturing department could not support her. If a (hypothetical) lens design needs to satisfy 100 parameters, more than 50% of these would have to be fulfilled by the manufacturing department. Modern Leica lenses and their exquisite quality would be unthinkable without the control in the production line. This is a not well known fact: the designer is nowhere without support from the manufacturing guys. But the designer is restricted in more ways. A lens has certain physical dimensions. If you would free a designer from the physical constraints he can perform wonders. The famous lenses for the Contarex series followed this paradigm: whatever the physical dimensions, the optical performance may not be jeopardized. Result: ergonomically the lenses were often hardly usable. So the designer needs to serve very many stern masters. The relative neglect of the 1,4/50 since more than 20 years might be the consequence of all these considerations. Now Leica has introduced a brand new 1,4/50 for the R-series. Any tester will be challenged to assess its performance against the background I just outlined.
The ASPH riddle.
Leica has introduced in recent years several lenses with one or two aspherical surfaces. Generally the image quality of these designs is quite high, to say the least. Some observers of the Leica scene have erroneously concluded that the equation aspherical=high image quality now has universal validity. Some even went further and deduced that any lens design without an aspherical surface can not be designated as a modern design. Occasionally one will hear or read the statement that for example the current Summicron 50 lens for the R series is an old design and needs or will be superseded by a newer design of invariably aspherical signature. It is easy to be charmed by such reasoning. This assumption, however, is not correct. First some facts. One: the new Summilux-R 1,4/50 (subject of this report) has been designed with conventional means. We can then conclude that the Leica designers could realize the required level of image quality without recourse to aspherical surfaces. If the use of asphericals would have been advantageous for the state of corrections and the production requirements, Leica certainly would have incorporated them. Two: aspherics are not always the best way to go. The Ricoh 28mm uses two aspherical surfaces but its image quality is below that of the Leica 28mm and the Zeiss 28mm for the G-series, both without asphericals. Three: all Zeiss lenses for the G-series are quite recent designs and none of them has any aspherical surface. The image quality of these lenses is beyond any reasonable doubt.
One of the main reasons for employing asphericals is the correction of spherical aberration and attaining a flat field free of astigmatism. But the use of asphericals may also affect other aberrations in a dangerous way, especially if the distance between diaphragm position and aspherical surface is relatively large. The design of an optical system must always try to balance many demands and variables, some of which are optical and some of which are manufacturing oriented. It could be that a designer tries to incorporate an aspherical surface only to find out that the strain on production tolerances is too heavy. He also could note that given the overall configuration of his/her design, the aspherical surface has no added value, or even will enlarge or introduce other aberrations. Note that any optical system must be regarded as a delicate whole of carefully designed and matched components. Note also that all aberrations act on every image point in conjunction. Note further that ‘image quality’ is not a fixed set of parameters. Zeiss will adjust the balance of corrected aberrations and the magnitude of corrections according to different rules than Leica does. Leica may conclude than given the required correction in some cases aspherical surfaces are justified and in some cases not.
The question of old designs.
I have no idea when and why a lens can be designated as ‘old’. The current Summicron and Summilux 50 and 75/80m lenses (include also the current Zeiss Planar lenses) are all variants of the double-Gauss type of optical classification. This design is now almost 100 years old. The general formula of a lens may be ‘old’.
Important is however not the general design but the state of corrections. A small change in curvature, different location of the diaphragm, different glass types and small changes in the distances between lens elements may alter the image quality quite substantially. Important is not the age of a design, but its optical performance. If a certain design has state-of-the-art image quality, it is a good design whatever its original optical formula or its year of introduction. If a lens fails to deliver, however old recent its design, it is a bad lens.
It is really that simple.
The current Summicron-R delivers (close to) state-of-the-art image quality and it is questionable if a new design would be substantially better without augmenting the selling price severely. Who then, given the current level of Leica prices would be willing to buy it? The very high level of corrections of the current Leica Summicron 50mm lenses is a tribute to the excellent quality of the designer team more than 20 years ago (Dr Mandler as example). One must stay realistic: without any doubt it will be possible to improve on these designs. Whether the improvement will be visible enough for the user to justify a much higher price is a BIG Question.
The question of comparisons.
As said earlier the designer will encounter many high order optical aberrations of increasing complexity as the aperture and/or the field angle become wider. A 2,8/100mm lens as example is much ‘easier’ to correct to a high level than a 1,4/35mm. The design-complexity might be a factor of 10 higher. It is an unwritten rule that only classes of lenses with the same order of complexity may be compared directly.
The question of contrast versus resolution.
The definition of image quality has changed over the last three or four decades. Partly because we have better understand ing of the eye and its vision and partly because we have better knowledge about optics. In reality contrast and resolution are two sides of the same coin. If we have high contrast we also have high resolution. The confusion is in the other direction: we can have very high resolution but low contrast. Good clarity of fine image details (as needed for HQ 35mm photography) however must have high contrast till the cutoff frequency (see below). That is at most 40 mm to 60 lp/mm and at this level contrast and resolution are in fact interchangeable. Popular testing however often lags behind and uses the expectation profile for any optical design as formulated twenty or even thirty years ago. In popular testing light falloff and corner resolution (or sharpness or contrast) figure prominently as ‘bad’. Now strong vignetting is certainly bad. Slight vignetting and also slight drop of contrast in the far corners actually might improve the overall image quality. The designer can balance the conflicting design issues to a higher level if he does not have to pay that much attention to what might be called cosmetic flaws.
A topic quite relevant for the Summilux test is the so-called cutoff frequency. It has been first established by Zeiss that the maximum resolution and the contrast at that figure are not really important for assessing image quality. As example the seven element Summicron 50mm from 1954 has a resolving power of far beyond 100lp/mm, but the contrast is below 5%. Not exactly visible therefore. But the low contrast noise that is being produced by this state of affairs impairs the visible quality severely. In most picture viewing situations (transparency projection and enlargements) we are looking at the image from a certain distance. If you look at a projected transparency from about one to two meters it is impossible to see the 40lp/mm. The eye simply has not enough resolving power at that distance to perceive this fine level of detail.
Most MTF graphs give results for 5, 10, 20 and 40 lp/mm. It can be proved experimentally that the 5 and 10 lp/mm are responsible for the overall impression of image quality. The 40lp/mm refer to extremely fine detail in the original object. And the 20 lp/mm define the limit of details than can be usefully recorded on film. It is also the limit of what we refer to as the clarity of fine image detail. In a way it is the cutoff frequency. Above this limit we find the optical properties that are mostly responsible for image impact. Below this limit we get an unfavorable signal-to-noise ratio and we need quite sophisticated detectors to record even finer details with good clarity. On the optical bench it is easy to demonstrate that contrast is more important than resolving power. I conducted the following experiment. I focused the Summilux with maximum resolving power in the center. The outer zones dropped dramatically in contrast and the whole image became soft. Then I refocused with maximum contrast at the 20lp/mm. The overall image quality improved as expected. The image now has very good contrast and excellent clarity of fine to very fine details. Any designer then has to define his own mix of components of overall desirable image quality and balance the optical design accordingly.
Test report of Summilux-R 1:1,4/50 (#3797918).
At full aparture this eight element lens is of medium to high contrast and thus very visibly above the low to medium contrast of the seven element predecessor. This is quite a performance as conventional wisdom will tell you that more lens elements will degrade contrast. Very fine detail is recorded with good clarity from center to well into the outer zones. In the far corner area a slight drop in performance can be noted. At f/2,0 the image outlines crispen, as does the rendition of extremely fine detail and at f/2,8 overall contrast improves again. Contrast of the extremely fine image details now is of a high order. In comparison to the predecessor we may state that the new one at f/2,0 is very much improved over the old one at f/4.0. At f/4,0 the new lens begins to record extremely fine detail with clear and crisp edges over practically the whole image field, the far corners excepted. From f/4,0 to f/8,0 this lens has its optimum. From f/11.0 diffraction starts to lower the contrast of very small image details. These small apertures are only needed when extended depth of field is required.
Closeup performance (±1,0 meter distance) is at all apertures excellent. Curvature of field is much improved when compared to its predecessor. We still can observe in the far corners a drop in contrast at all apertures. Light fall off in the corners at full aperture is hardly visible. Deliberate two stops underexposure failed to bring out strong vignetting. Veiling flare at full aperture is negligible. Suppression of light halos around small subject details is excellent and careful comparison shots with the Summilux-M 50mm showed the R version to have a slight edge.
The sharpness-unsharpness gradient is quite smooth and subject shapes are very well preserved in the unsharpness zones.
General conclusion.
The new Summilux-R 1:1,4/50 offers excellent image quality and Leica R users can now shoot in available darkness and fully exploit the capabilities of modern emulsions. To be quite clear: if you need to record extremely fine detail to the last possible minutest image point, the Summicron is to be preferred. For my formal comparison shots I use Kodachrome 25 and 64, as these films still give the best sharpness (read contrast) for very fine image details. Stopped down one or two stops the new Summilux-R has that enviable balance of sharply rendered crisp detail and smooth gradient of color hues within small subject areas that is Leica’s current fingerprint. The image recording capabilities of this lens far exceed the one offered by all current ISO400 films and are on a par with the best of the ISO100 films. Kodachrome 64 would be an excellent companion.
The outstanding capabilities of this lens are its high level of detail recording from axis over the whole field and its ability to crisply recording extremely fine details when stopping down. In this respect the predecessor lacked some qualities.
In comparison to the Sumicron-R 2/50 the new Summilux is an improved design. Optical aberrations ( especially curvature of field and astigmatism) are tightly controlled, and at f/4 to f5.6 the Summilux-New edges ahead of the Summicron-R. Compared to the Summilux-M the differences at full aperture are small, but not inconsequential. On axis performance is more or less equal, but the R wins in the field, significantly! At f/2,8 the M version records extremely fine details with commendable crispness, softening when going to the corners. At f/5,6 we see a level of performance comparable to the Summilux-R New. With one big exception. The M suffers a bit from loss of contrast especially in the tangential plane.
Summarizing:
The new 1,4/50 Summilux-R defines the current state of the art of large aperture standard lenses. It outclasses the previous version of the 1.4/50 Summilux-R by a clear distance. It edges ahead of the current Summicon-R and improves upon the current Summilux-M 1.4/50. Nonscientific comparison pictures with the Summicron-M show comparable performance in most picture taking situations, however. The current Summicron-M is still the high speed standard lens to beat.
The Mandler era is not yet over. If you need the utmost of recording capabilities the new Summilux-R needs f/2 or smaller. Its wide open performance is excellent and short of outstanding. Modern Leica lenses are exquisite examples of the Solms wizardry. The new 1.4/50 Summilux -R production samples have better MTF graphs than the theoretical predictions: proof of a very refined mechanical production system and very tightly hold tolerances.
Vario-Elmarit-R 1:2.8-4.5/28-90mm ASPH
Introduction




This is a new zoomlens, designed and manufactured by Leica, Solms, that has a remarkably long list of innovations. First: this is the first zoomlens with a range of more than 1:3, to be exact: 1:3.214, close to the magical number pi (3.14....). Second there is a new method of mechanical movement to ensure an almost frictionless smoothness of focal range selection and distance setting. Thirdly there is a new method of assembly that minimizes tolerances to a narrow range. The zoomrange covers 90% of the most frequently used focal lengths,as a study by Canon, some years ago indicated. The analysis of thousands of pictures indicated that the statistical mean was a shutter speed of 1/125 and an aperture of 1:8 at a focal length range from 28 to 90mm, with the 135mm as a quite often used lens, but now almost extinct. The aperture starts at 1:2.8 and ends with 1:4.5, which is very good, considering that one of the closest competitors, the Zeiss Vario-Sonnar-T* f/3,5-4,5/24-85mm starts at 1:3.5 (and 24mm). The Leica literature now uses the Zeiss designation with f/2.8 and not the classical Leica designation with 1:2.8. What is in a name, mused Shakesperare.
The Leica designers have to wrestle with the following problem. If you study a modern handbook about production technology, you will find that for small production batches (typically 500 to 1000 pieces) CNC machines have to be used. It is not cost effective to do dedicated machine tooling to produce the required parts. Economy of scale is not possible. CNC tools are very flexible, but quite expensive and there are technical limits to the designs that you can manufacture with this technology.
Given the small batches of production, one can only use the time honored method of hand assembly. There is no use employing robots ar other automatic methods of assembly. One of the arguments to use as low a number of lens elements (besides the optical ones) is the additional effort during hand assembly: every additional element implies an additional cause of errors and an additional step in the quality assurance chain.
These facts of life can be seen as advantages too: Lens design and assembly methods can be integrated already at the initial stages of the optical design. The normal way of operating is to divide the total task in two unrelated subtasks: the best possible optical design and the best possible method of assembly. The connection between the two is a statistical analysis of the error distribution of the manufacturing tolerances and the assembly process. The idea is to find the widest range of tolerances before the required image quality drops below a precisely defined limit. Assume that you specify an MTF value of 60% at a certain location in the image field. Your tolerance range is ± 10% (assumed average) : you will accept every lens that will perform within a 54 to 66% range. If the tolerance analysis indicates that a certain lens element can be decentred by x%, before it will effect the final result to a level below 54%, this decentring may be accepted and the quality assurance can be adapted to this knowledge.
The Leica designers nowadays approach the problem from the other perspective. They know the possible accuracy of the CNC tools and they know the precision with which human beings can assemble parts and they know the precision of the equipment to adjust the assembled parts. They can design a lens in such a way (calculating an aspherical surface as example) that they know for sure that this shape can be manufactured within a very narrow tolerance in order to avoid adjustments and compensations during assembly. The optical design is already taking into account the limits of manufacture and assembly and the construction can already be prepared for tolerance compensation to stay within narrow limits.
The optical specs and the mechanical construction.
The designer of a zoomlens has in fact a luxury problem: he has a larger number of lens elements to correct lens aberrations than are available with a fixed focal length. That is the reason why the best zoomlenses can deliver quality above that of fixed focal lengths. With the exception of the maximum aperture: here the fixed focal lengths are still unsurpassed. Fixed focal length lenses are totally stationary: the lens elements are fixed and there is only a helicoil movement to change the total lens group (with the exception of 'floating elements'). In a zoomlens we have several lens groups that move in relation to each other in a complicated way and they have to move with a very high precision. One needs a different mount: one in which the cylindrical mount has a number of slots (curved lines) in which the guiding rollers slide to govern the movements of the separate lens groups. When you have a two group zoom (as is usual with the Leica lenses) this mount can be made with the required structural stability. The new lens has a three group zoom design and in this case the number of slots in the mount would be destabilizing the cylindrical mount. Leica has employed a new method (as far as I know unique in this area) and has designed a mount where the slots are milled into the inner surface of the aluminum mount with the help of CNC machinery, designed by Weller, a previous Leitz Wetzlar subsidiary. There are numerous chisels that work at the same time to cut into the inner walls of the mount to get the required shape and precision. The challenge here is not only to operate at an accuracy of 0.01 to 0.005mm, but also to ensure that the surface roughness is also below these tolerances to ensure a smooth movement.

The usual requirement at Leica is a mechanical tolerance of 0.01mm. But in this case there are additional requirements. The surfaces of the lens elements are manufactured to a tolerance in the nanometer range. (aspherical shape and surface treatment to allow the new methods of coating). These lenses must be fitted into the mounts and assembled without the slightest stress or strain. This could deform the shape of the surface and generate a drop in performance. This is not easy with normal mechanical methods and hand assembly. Leica now uses a method of integrated mechanical compensators. This is a mechanical device that is already integrated in the original lens design and mechanism to make very small adjustments during assembly to minimize the tolerance bandwidth.
During the subassembly and testing of the lens with high magnification MTF equipment, any deviation from the norm can be adjusted without re-assembly or adding shims or negative/positive lens elements.
The lens consists of 40 main parts (without lens elements and electronics and aperture mechanism) and it takes an average of two hours to assemble the parts.
The lens has 11 lens elements in 8 groups and has two aspherical surfaces, one in front and one at the back (like the old Noctilux).
The minimum focus over the whole range is 0.6 meter. A macro facility is not available, but at 90mm one still has that 0.6 meter near focus and that is acceptably close in many situations.
Performance
The Vario-Elmarit-R f/2.8-4.5/28-90 mm ASPH is an excellent performer at all apertures and focal lengths. A fixed focal length can be optimized for one distance (or magnification) and this is usually the infinity position. A zoomlens can be corrected for one focal length, usually the one in the middle and both extremes suffer. With this lens, we see a gradual improvement form the 28 position to the 90mm. Generally we may note that the performance over the whole image area is very high, where the fixed focal lengths often have a very high quality in the center portion and a gradual dropping towards the corners.
At 28mm and full aperture (2.8) we have a high contrast image that can record above 150 Lp/mm in the centre of the image and more than 80 lp/mm in the outer zones. Only the corners are weak with a soft recording of fine detail. Stopping down to 5.6 the performance of the centre now extends over an image circle of 12mm diameter. There is no trace of astigmatism and a slight field curvature. Some colour fringing is visible at very high magnifications. Distortion is visible with -3% (barrel distortion) and so is vignetting at 2.5 stops. Compared to the Elmarit-R 1:2.8/28mm, the overall contrast is a bit lower and so is performance at the corners.
At 35mm and full aperture (2.8) there is a small improvement in the outer zones where the lens now records 100 lp/mm with good micro-contrast. Distortion now is about -1%. At 5.6 we have optimum performance with a crisp rendition of very fine detail over most of the image area. Vignetting is practically gone. Compared to the Summicron-R 1:2/35mm the vario version has an improved definition in the outer zones and a crisper rendition of small details.
At 50mm and full aperture (3.4) we see a very high contrast and an exceptionally high resolving power of more than 150 lp/mm over a large section of the negative. There is still some faint colour fringing, but in practice one would be very hard pressed to note it. At 5.6 we have impeccable performance that easily surpasses the quality of the Summicron 50mm lens, especially in the outer zones of the field. At this aperture the Summicron has less definition of the very fine details. Most people have never noticed this drop of performance in the Summicron, and this is an indication of the very high quality of the new zoomlens
At 70mm and full aperture (4) the image quality becomes superb and we have an extremely high contrast and a very crisp definition of the finest details. Stopping down to 5.6 does improve edge contrast and now the corners are quite good too. Distortion is 1% (pincushion) and vignetting is negligible.
At 90mm and full aperture (4.5) the best performance is reached and compared to the 70mm position the outer zones and corners are now as good as the centre of the image. Vignetting is gone and distortion is very low with 1%. The low distortion at the tele side of the zoomrange is quite remarkable. A comparison with the Apo-Summicron-R 1:2/90mm ASPH shows that this lens has the same perforamnce at 1:2 as the Vario lens at 1:4.5. Still the vario lens has a slightly higher impact, because of lower internal reflections and a smoother unsharpness gradient.
Flare properties
I made a special study of the flare properties of the lens, as this is the one area where lenses have to go ‘a bout de souffle’. Veiling glare is hardly visible at all focal lengths, implying there is no loss of contrast when the background is much brighter than the subject itself. When the sun is obliquely shining into the lens, and is behind the subject, one can see some secondary reflections of small extent in the picture, but the well-known diaphragm blade reflections are not visible. With the sun flooding the image, there is of course a bleaching out of the picture details, but in such a situation one would change the position slightly to evade this direct confrontation with the sun.In general I would say that for veiling glare the lens is better than the average Leica lens, and for secondary reflections it is slightly better.
Conclusion
This is a lens with amazing characteristics. It offers outstanding quality and can be compared very favorably to the fixed focal lengths. A detailed comparison with the equivalent fixed focal lengths is now possible based on the published graphs in earlier chapters and in the lens data sheets, available separately on the Leica website.The reader can do this him/herself. In general the fixed focal lengths will be more compact and offer a higher speed per focal length. Stopped down there is no longer a big difference and compared to older lens generations, the zoomlens often has better imagery in the outer zones of the image.
The images made with the Vario-Elmarit-R f/2.8-4.5/28-90mm ASPH have a very good colour fidelity, a very fine pictorial depth and documentary realism. This is a lens for slide film and if you have not yet tried slide film, the acquisition of this lens might be a good incentive to try these films.
The wide zoomrange from 28 to 90mm highlights another property of the reflex system: the normal finder screen of the R8/9 is a bit too dark at the 90mm position and it is difficult to focus accurately at the 28mm position. Focusing at the wide angle range is often not very critical as depth of field will cover slight errors. If accurate focus is required, it is best to focus at 70mm and zoom to 28mm (or 90mm and zoom to 35mm).In this range, focus constancy is absolutely spot on.
Summicron-R 1:2/180 APO and Elmarit-R 1:2.8/180 
The subject of this test report are two lenses, the APO-Summicron-R 2/180 (1994) and the APO-Elmarit-R 2.8/180 (1998).
I used the MTF graphs, the optical bench (projection) test and a long series of practical shooting. All pictures were done with Velvia and Elitechrome 100 and Kodachrome 25/64. Also the Ilford XP2 Super was used extensively. The R8 body (one of the few with the blue display!) was attached to these lenses and once again. I was impressed by the extremely intuitive user interface of this camera. Yes, it is heavy and big and yes it looks large. The 2/180 however is a tripod only lens and on tripod (location and studio) you do not notice the bulk of the R8, only its extremely efficient functioning as a photographic tool. The F position is perfect. In the studio you attach your flash unit to the R8: measure the flash intensity (spot metering only), adjust the aperture and you shoot. The slides were exposed perfectly. On location I shot fashion type pictures at dawn. Why? The f/2 aperture gives very nice out of focus background and the semi-dark situation tests the contrast of the lens wide open. The exposure of 2 seconds at f/2 is beyond the capability of most AF sensors. So manual focusing is a must here.
I always wonder why R8 comments focus on the feature of AF. There are many situations where AF is not needed or not possible and the R8 is a camera, designed for work in those areas where AF may not be helpful or necessary. Of course the AF feature is nice to have and in many instances imperative, but the R8 is an instrument for those picture taking situations where manual focus will do fine or must be used. It is a different perspective, but indeed, judgment of the capabilities of the R8 must be made after extensive use of the camera and its lenses in many environments. The lack of AF may be sorely missed sometimes, but the camera has a lot to offer beyond AF.
Ergonomics
The 180 pair as example is of such optical performance that you may wonder if AF can handle it. The depth of field of the 180mm at f/2 and 2.5 meter is about 1 cm (10 mm). That's pretty accurate and any AF system would be hard pressed to focus that accurately. It is by the way a new experience to use such a lens with DoF even less than a Noctilux. The Leica documentation mentions that the 2/180 can be used hand held and used on a monopod. This you can forget. A slight movement will generate unsharpness at full aperture. So this a lens for stationary use, landscape, portrait, nature, wild life, the fashion cat walk. You name any location where a high speed, very contrasty lens needs to be deployed (because of subject and exposure) and the 2/180 is your companion. The extremely high quality of this lens is not degraded by the permanently attached protective filter in front of the lens and will fuel the discussion of the use of filters. If ever a lens challenges the still conventional wisdom of contrast versus resolution and the role of image quality in relation to artistic intention, it is this lens. Of extremely high contrast, the 2/180 also exhibits a rarely seen definition of fine detail and a very distinctive unsharpness/sharpness gradient.
The 2.8/180APO is on the same level of image performance if not better. Part of the magic of these lenses is the internal focusing, that improves imagery significantly and also gives the smoothest focusing this side of the Mississippi. This lens is handholdable, but best performance will be extracted when the lens is supported. The perspective of the 180mm in combination with the distinctive background blur are excellent for portraiture, full figure and fashion/glamour photography. The rendition of the finest detail in the subject sets a new standard and the overall contrast brings in detail and a new level of penetrating power for long distance shots. The 70-180 Vario lens has an excellent 180 position. But both these 180 (2 and 2.8) are better and if you need the ultimate in performance one of both is the choice. The 2/180 has obviously more weight (2.5 Kilo versus less than a kilogram) and a much larger diameter. The full stop advantage may be crucial and so the choice should be made very carefully. We look at these aspects at the end of the report. I will close now by noting that the 2.8/100 is dethroned as the reference lens for the R line. Both the 2 and the 2.8 focus past the infinity mark. The additional distance is more than 5 millimeters. The amount of glass and metal in these lenses is such that thermal expansion becomes an issue. The free space beyond the infinity mark has thoughtfully be provided so that whatever the temperature the true infinity focus can be used. 
On test
The Elmarit 2.8/180 at full aperture gives an exceptionally high contrast over the whole image field, and exceedingly fine detail is defined with crystal clarity and excellent edge contrast. This performance extends over an image height of about 10mm, (that is an image circle of 20mm). The outer zones reproduce the details with a slightly lower contrast and a bit more fuzziness at the edges. The apochromatic correction delivers true apo quality over the whole image field to the corners (no color fringes whatsoever). There is no decentring, no distortion and no vignetting. (you can measure a bit of light fall off, but is not discernible on the slides). Stopping down does not improve the image quality. The corners and outer zones become a shade crisper though. At f/8 the contrast drops a bit and thus the optimum is below f/8. But from f/2.8 to f/5.6 the performance is on the same level and so the full aperture is not only a very useful one, but also the optimum. After f/8 to f/22 the contrast is a bit below optimum but overall image quality is above comment and so we have one of those rare lenses that can be used with utmost confidence from 2.8 till 22. Close up performance ( about 2 meters) is absolutely equal to the infinity setting. There is some pincushion distortion, however. The overall imagery is even a fraction better than at infinity. This is a most remarkable behavior and can be explained by the mechanism of internal focusing. Only one lens element inside the lens moves when you focus and the designer has very skillfully used this shift to correct the close up performance. Not a real floating element, but sort-of, so to speak. This lens delivers optical quality of a very high order indeed and is the best Leica lens I ever tested, better than the 2,8/100 (R) and the 2/90 (M). This lens alone would be a sound reason to buy into the R system.
The Summicron 2/180 at full aperture is almost on the same level as the Elmarit at 2.8. The overall contrast is exceptionally high and over an image height of 5 to 6 mm (image circle of 10 to 12mm) exceedingly fine detail is defined with excellent clarity and exceptionally high edge contrast. In the outer zones the contrast drops visibly, when one looks the definition of the very fine detail. Outlines of subjects are defined very crisply. The far corners are quite soft and fine detail, while clearly visible is soft with fuzzy edges. Stopping down to 2.8 improves micro contrast in the outer zones and now the performance is almost identical to that of the 2.8/180. Further stopping down improves the micro contrast of the outer zones, but now the on axis performance drops a fraction. Vignetting is not detectable on slides, taken at full aperture. There is a very faint decentring. Apo quality is as expected. No fringes, hardly any astigmatism etc. Close up performance is identical to infinity performance and can be explained by the same mechanism as in the Elmarit 180. The outstanding property of this lens at full aperture is its definition of the smallest possible detail with a very high micro contrast and overall contrast. On location photography in twilight and semi-dark level of exposure (50 ISO at 1/4 to 4 seconds) shows an excellent power of penetration of distance: fine detail at a distance of 50 meter in very low contrast light is defined with outstanding edge contrast and subtle shades of colors are recorded with high fidelity. Colors itself are clean and transparent. Shots of models at about 5 to 10 meters in the twilight record details not visible with the naked eye. Portraits close up produce pictures with a very pleasing perspective and a recording level (even at full aperture) that would be a challenge for any medium format lens to equal. Summing up.
To summarize this part (the next one will look at flare, unsharpness gradient etc): both lenses are the two best lenses I ever encountered within the Leica stable. The 2/180 is obviously a tripod only lens and performs superbly in its intended application: location and studio photography in a stationary situation. The catwalk is an obvious deployment as is model (glamour?) photography, where the low light capabilities of this lens extend the limits of twilight photography. Nature, and animal photography are also suitable areas. The 2.8/180 is a bit more versatile as it can be used handheld. Both lenses have an extremely shallow depth of field (the Summicron at 2 to 3 meters operates at about 1 to 3 cm!). The accuracy of the R8 is fully capable to handle this and you can be assured that the plane you wish to focus on, is indeed recorded with the best image quality. These lenses approach the ideal of a lens, that gives optimum performance at full aperture, do not degrade when stopping down and perform as well at close distance and at infinity and give equal image quality over the whole image area (2.8) or a big portion of it (2.0). 
Flare and unsharpness gradient.
The general idea of flare in fact consists of three distinct phenomena. Stray light or veiling glare, that is unwanted light that is distributed over the whole image area and reduces contrast and lightens up the deeper shadows. Then we have secondary or ghost images that are caused by small light sources, that are reflected by lens surfaces. And then we have halos around point sources as when we take night pictures of lampposts that are surrounded by a strong halo. Secular highlights also are affected by this as highlight details are washed out. Of course these phenomena are not unrelated, but have different manifestations. The 2.8/180 does not exhibit any stray light, blacks are deep dark and light sources are very tightly delineated. Specular highlights show finely graded shades of white and secondary reflections are only observable under very unfavorable and seldom encountered circumstances.
The 2/180 again does not have any stray light and for such a lens it is amazingly well behaved here. Halos are also very well suppressed although a shade less than the 2.8/180. Secondary images can be seen when shooting straight into the sun or another strong light source. When the light source is just outside the image area, and very oblique, then we may see in certain but not all situations, a veiling glare that can be distractive. The excellent suppression of stray light shows in the details that hold contrast and gradation. This topic should be approached with some care. It is always possible to force a lens in a situation where flare of whatever character will be visible. Both 180 lenses are extremely well shielded from flare, and one really needs to some optical aerobics to induce flare, and then only in the area of ghost images and bright spots of some extension. In 99% of situations both these lenses can be used without any consideration for glare.
The sharpness/unsharpness gradient is obviously related to depth of field. It is not well known that the DoF extension (distance before and after the sharpness plane) only depends on the reproduction factor. That is, when two objects are photographed are of equal magnification, irrespective of the focal length, the DoF is identical. In practical terms, an object taken with a 35 mm at 3,5 meter and the same object taken with a 180mm at 18 meter will have identical DoF. So if we wish to compare the unsharpness impression of two different lenses, or make any general statements. we should take care to compare pictures taken at equal magnifications.
Finer points of difference between the 2.8 and 2 version is the somewhat smoother gradient of the 2.0 lens. At the same reproduction factor and same distance before/behind the subject, the detail rendition of the 2.8 is slightly harsh, that is outlines of detail are quite crisp. maybe a bit over-crisp. The 2.0 produces a bit more washed out patches of color. The wider aperture is responsible for a big part of course here. When stopping down to 2.8 the Summicron approaches the Elmarit, but stays on the soft/fuzzy side of detail outlines. Whatever you prefer, you need to do some careful comparison here to make up your mind. There is a character difference here, base partly on the correctional choices. The Summicron might reproduce the background unsharpness a bit less pronounced and so help focus on the main subject.
General conclusion
As general conclusion I may note that the 2.8/180 is by a small notch the best, closely followed by the 2/180 which has a slightly different character of rendition and by some distance the 180 position of the 70-180 vario lens. The 180 is a premium focal length and Zeiss with a 2/200, Canon with a 1.8/200 show what their designers can do when reigns are loosened. Within the R line these two lenses would be enough to convince anyone to try the Leica R for optical prowess.
Vario-Elmar-R 1:3.5-4/21-35mm ASPH
 
The new VE-R 21-35 is a very compact zoomlens, that fills the gap in the line-up of the VE-R 4/35-70 (aspherical but not indicated as such), and the VE-R 4/80-200. Together these three lenses allow a range of 1:10 (21-200) to be covered and should be deployable in 90% of all photographic assignments. The optical performance of these three lenses is quite identical and Leica has done its job very well. When doing slide shows, pictures taken with the three lenses will give comparable image quality and so lenses can be used as needed without worry.
Of course you will see small and fine differences in performance in the lab, but these do hardly translate into visible differences in practical circumstances.
This has not been the case in the past. Leica has been a late starter in the zoom domain, but made up with excellent performance. It is the work of Mr Kolsch, who is undoubtedly now the best Leica designer ever. It may be a surprise, but almost always the new zoom-lenses surpass or at least equal the performance of the fixed focal length lenses at the same apertures of course.

Every optical system has a range of aberrations that can be traced to the specifications (Aperture, size, weight etc). Every lens has its own set of parameters (glass type, curvatures, focal length etc) that can be employed to correct the set of aberrations. Obviously not fully, but it is the designer’s task to push the residual effect of aberrations into less visible domains. With fixed focal length lenses the individual lenses are in a fixed (stationary) position and so are deprived of one important correction opportunity: the shift in location. Floating elements are a useful means with these lenses to improve performance in the close focusing range. Zoom-lenses are more complicated to understand and correct, but if the designer gets the knack, he can use the two or three sliding groups of lens-elements for improved correction. Computer programs do not help you that much. You need to have it between the ears and if you lack the insights, no computer can save you.
The Ve-R 21-35 is ergonomically a beauty. It is very easy to use, extremely smooth (much better than some other zoom lenses in the Leica stable) in its focal length and distance movements.
Optical performance.
The VE-R 21-35 has only 9 lenses in 8 groups, and two aspherical surfaces. (The Canon 3.5-4.5/20-35mm has 12 lens elements in 11 groups). Here you may see a stroke of mastery. Add the aspherical surfaces to the count of elements, than it is 11 elements, still less than the Canon).
The high overall contrast and clear transparency are the result. If few lenses have much to do, the production tolerances must be low and accuracy of assembly should be high. Decentring is a good indication of quality of assembly. Measured the decentring was zero!
Distortion is slight at the 21 position and just visible in big projections. At 24mm the distortion is very small and at 28 it is gone. So the classical change from barrel to pincushion distortion is not detectible with this lens. Vignetting at full aperture is not visible. Natural vignetting does exist as always and with a half stop is very small and can be neglected as the transition from center to corners is very gradual.
One of the most important aspects of a zoom lens is its focus constancy, meaning than a refocus is not necessary when changing focal length. Often you can notice this: focus on an object at the wider setting and zoom in: you need to adjust focus. This is caused in part by the inaccuracy of the ground-glass focusing but part by this focus shift. You will notice this not as a drop in contrast, not as an unsharpness, as the shift is small.
So I made an accurate measurement of distance and contrast with the lens at 1.5 meter. The lens was set to the 21mm position and measured. Then without changing anything but focal length to 35mm, the measurement was repeated. No detectible change: again a tribute to accurate manufacture.
21mm
In the center till image height 12mm (image circle 24mm) at full aperture (3.5) very high contrast and excellent edge definition of fine details. In the corners the image is softer, but quite visible. At 5.6 the image becomes very crisp with good clarity of the very fine details till but not including the far corners. Till f/11 there is no change in performance and after that the image softens a bit. Astigmatism is slight and coma and flare are well corrected. No trace of colour fringes at black-white borders. At full aperture close up performance is already fully useable, but stopping down will enhance the quality when demands are very high.
24mm
image performance pattern is identical to that of the 21mm. At image height 12mm the edge sharpness is a bit better. At 5.6 a very even performance over most of the image area has been reached. At f/16 a drop in contrast can be detected.
28mm
Contrast at full aperture (1:3.7) is even higher now and the image circle of best performance is 30mm (15 mm image height). At f/5.6 the definition of very fine details is very crisp including teh corners. At f/16 the usual drop in contrast is visible.
31 and 35mm
At full aperture a very even high performance image can be noted. Who is interested in these matters may note a resolving power of more than 150 lp/mm with clearly detectible line patterns. At /5.6 the otimum is reached.
The performance yardstick.
The relative performance differences are recorded at a magnification of 100 times. That is a slide projection of a slide 4 meters wide. looking at details in close distance. When you use this lens in less demanding circumstances the relative performance differences may be less visible: that is corner quaility might be as good as center quality in visual inspection.
Comparisons.
The older Super-Angulon 21mm has significantly less overall contrast and much softer definition of fine details. The Elmarit-R 24mm has good center performance but much softer recording of fine detail in teh outer zones and blurred edges of very fine detail.
The Elmarit-R 28mm has a slightly higher overall contrast and of course one stop wider aperture,
The Summicron-R 2/35mm is at apertures 4 and 5.6 a bit weak and has lower contrast. In the center the Summicron can hold its own, but overall it is an older design and this shows.
Is aperture 4 too less for demanding professional work?
If you wish to use the lens in low light environments, there is of course a natural limit. The first limit is the brightness of the finder screen, and not the photon capturing properties of the lens itself. even in dimly lit coffee-shops, I could make handhold pictures with 100ISO film. It is a matter of taste partly. If 1/8 with an f/4 lens is too less, then you might ask yourself if 1/15 at f/2.8 makes the day in every situation. In practice the aperture of f/4 has a useful DoF in many situations where you would have to use this aperture anyway, even with an f/2 lens. No doubt sometimes the f/2 or f/1.4 lens is imperative, and Leica have these in the stable.
Overall.
The Ve-R 21-35 asph has an optical performance that equals and in many cases surpasses the comparable fixed focal lengths and delivers very punchy images. The operation has the solid smoothness we do demand from Leica but do not always get. The range of 1:1.7 seems a bit on the low side and looks more limited than it is in daily use. You need to adjust to the lens powers and do not judge solely from first experiences. To designate the usual areas of landscape or reportage as the preferred areas, is a bit short around the corner. Situational portraits, human interest scenes in close and tight quarters and everything that can be imagined by the photographer to benefit from a wider perspective in close distances can be captured with this lens. It is the photographer not the lens that defines the subject. The Ve-R 21-35 is very pleasant to use, compares favorably to companion lenses, has excellent to outstanding performance and gives the user a new range of creative possibilities.

Super-Elmarit-R 1:2.8/15mm ASPH.
General remarks.
The very wide angle of this lens and its short focal length bring advantages and restrictions. The extended depth of field makes the concept of 'boke' obsolete for this lens. Even unsharp areas in front and beyond the sharpness field ('plane' would be the wrong word here) retain shapes and details and have a very smooth migration curve. On the other hand, the assumption that the lens is an easy one for pictorial representation is wrong. This is definitely not a convenient landscape lens. The large and extended foreground push main subject areas into the vanishing background. So you need to be careful when and where to deploy the lens. It is at its best when the sense of shape needs to be defined or when the overwhelming surroundings of some magnificent room or corridor or interior buildings have to be captured and visually communicated. Left: Super-Elmarit, right; Elmar 3.5

In short a visually sensitive photographer with a keen and empathic eye can do wonders with the lens. It is also very good for closing in on groups of people who share some activity. Back element focusing and is indeed incredibly smooth in its movement. The internal filter revolver is the same from the previous Elmar 15 and must be used as the filter element is part of the optical design. It focuses to 18cm.

At
full aperture we have a medium to high contrast image with excellent definition of very fine detail over an image circle of 12mm radius (24mm image circle in diameter). The outer zones and the corners are progressively softening but even in the extreme corners coarse detail is quite visible. When reading this one should reflect on the extreme angle of field. For this angle the definition over the whole image field is close to outstanding. A slight fuzziness at the edges of fine detail delineation softens the overall image a bit.
Distortion is very well corrected and even persons at the edges of the image retain their normal body contours. (Ever looked at the elongated faces and bodies of persons when using a 12 mm or some other 15mm lens). Architectural straight lines are straight lines with a just visible distortion in the outer zones of the image. Astigmatism and colour fringing are for all practical purposes non existent. For really demanding work (above 50 times enlargements of slides, there is some color fringing from 9mm radius). Vignetting is of course visible but not objectionably so. In darker grey areas it is not visible, but white areas or blue sky do show light fall-off.
Flare is commendably low: secondary images are not to seen and the veiling glare in contre-jour shots is confined to very small areas around the bright spots themselves. A good example is a picture of very fine telegraph or electricity lines against a light grey or white sky: if the lines are clearly differentiated and keep their own color (no greying) then the lens is OK. There is absolutely no decentring, which is some act given the large diameter of the lens elements.