Leica Super Angulon-R 21mm f/4

 

Introduction

Leica Super Angulon-R 21mm f/4 was first introduced in 1968 and remained in production until 1992. The f/4 variant actually replaced an earlier Super Angulon 21mm f/3.4 design, which was produced for only 4 years from 1964 through 1968 and was a non-retrofocus lens, thus requiring cameras with a mirror lockup. Technically speaking, Leica Super Angulon lenses were not even designed by Leica! Angulon brand name belongs to Schneider Optics, another renowned German optical equipment manufacturer, who designed Super Angulon 21mm as well as PC Super Angulon 28mm lenses for Leica. The 21mm f/4 Angulons are commonly available on the used market with good quality copied typically fetching ~US$600 (as of March 2009).

The optical construction of the lens consists of 10 elements in 8 groups. The build quality of the lens is superb, as pretty much with all Leica lenses - the barrel, the aperture ring as well as the focusing ring are all metal and built to last. The focusing ring is pretty smooth and the aperture ring snaps in into position with a satisfying click and requires a little bit of force to switch. The minimum aperture is f/22 and the ring moves in half f-stop increments. Due to the all metal construction, the lens is not the lightest among wide angles, weighing 410g (14.4oz). Size-wise, this is a pretty compact lens, measuring 78 x 53.5mm (3.07 x 2.1in), although the length of the barrel extends slightly during focusing towards the closeup. The minimum focusing distance of the lens is 20cm (8in) and the lens accepts 72mm screw-in type filters (Series 8.5 in Leica terms).

Image

The lens was obviously designed for 35mm film cameras, so if used on APS-C type dSLRs with 1.6x crop sensors, the lens would have a field of view similar to that of a 33mm prime on a full frame body. Like most Leica R lenses, Super Angulon-R 21mm f/4 can be easil adopted to all Canon as well as Four Thirds cameras using widely available adapters. Within the scope of this review, the lens was tested on Canon full frame and APS-C type cameras.

 

Summary
Lens Composition 10 elements in 8 groups
Angular Field 92 degrees
Minimum Focus 20cm/8in
Focusing Action MF
f-stop Scale f/4-f/22, manual
Filter Size 72mm (Series 8.5)
Lens Hood 12506 Metal (included)
Weight 410g/14.4oz
Dimensions 78x53.5mm/3.07x2.1"
Lens Case N/A

 

Field Tests

Leica Super Angulon-R 21mm f/4 is a classical manual focus lens. As such, its general functionality is similar to any other manual focus lens - you set the aperture manually, you focus the lens manually and that's pretty much it. Well, lactually ike all manual focus lenses adapted to an alternative mount, Leica Super Angulon-R 21mm f/4 needs special consideration when it comes down to focusing. Because of its relatively slow maximum aperture, focusing the lens manually is rather difficult - the camera viewfinder is already pretty dark at f/4 and by f/5.6 seeing any finegrain detail would require eagle eyes. Adapters with AF confirmation is another choice, although most confirmation adapters stop functioning by f/5.6, again because of the limited amount of light passing through the lens iris) and pretty much all AF adapters would fail by f/8. So then the only remaining choice in such cases would be the old tried and true hyperfocal distance focusing, using the DOF scale engraved on the lens barrel. Although you should keep in mind that a small aperture setting on a super wide angle lens like Angulon 21mm would give a such a huge depth of field that precise focusing in many cases would not even going to be necessary - in most cases focusing errors will be completely masked and you can literally set the lens to infinity and still get images with acceptably sharp near and far objects.

One thing you need to keep in mind if you are using a smaller, APS-C type body like Digital Rebel XTi, is that because the front of the lens is pretty wide, you might end up with some light falloff if you are using an internally built flash. The falloff is minial and is limited to the lower end of the picture frame, but you should still consider using an external flash rather then risk ruining your shot.

Image performance was somewhat mixed. The lens performed very similarly on both full frame as well as APS-C cameras - that's the good thing. The bad thing is that image quality around borders was noticeably worse then in the center. And that's throughout the aperture range. Typically, it is expected that any lens, and wide angle in particular, will be somewhat softer its widest apertures, however, Leica Super Angulon-R 21mm f/4 remained soft at f/5.6 as well as f/8. By f/11 border image quality does improve, but still is nowhere close to the quality in the image center, which by the way is top notch from f/4 and all the way down to f/11.

One major weakness with this lens is flare. As can be seen from the shots below, which were taken with the sun positioned close to the picture frame and hitting the front element of the lens at about 75 degrees from the right hand side, the lens produced both ghosting as well as glare throughout the aperture range. You also get the usual patches of lower contrast throughout the frame, which is quite typical with most lenses. The amount of flare the lens produces is simply ridiculous - it is as if the lens has no coating at all and the light bounces off the front element in all possible directions. The lens does come with a hood, and you should certainly use it in harsh lightning conditions.

 

ISO 100, 1/800, f/4, 21mm (Canon 5D)
ISO 100, 1/800, f/4, 21mm (Canon 5D)
ISO 100, 1/200, f/8, 21mm (Canon 5D)
ISO 100, 1/200, f/8, 21mm (Canon 5D)

 

The lens showed minor degree of vignetting on both full frame as well as APS-C cameras, however, for such a slow lens this is somewhat disappointing. At f/4 light falloff is visible around corners on a full frame camera and barely noticeable on an APS-C body. But by f/5.6 vignetting is pretty much gone on either camera.

 

Vignetting @ f/4 - full frame vs APS-C
Vignetting @ f/4 - full frame vs APS-C

 

Color handling was somewhat mixed. Color palette remained pretty accurate with well saturated colors that gave lively and vivid feeling to pictures. However, the lens also produced noticeable color fringing, with both lateral and longitudinal aberration visible in pictures, especially around image borders (you can clearly see color fringing around areas with high contrast transitions in the sample picture gallery below).

 

ISO 100, 1/1250, f/4, 21mm (100% crop)
ISO 100, 1/1250, f/4, 21mm (100% crop)


 

Lab Tests

Please note that MTF50 results for APS-C and Full-Frame cameras as well as cameras from different manufacturers are not cross-comparable despite the same normalized [0:1] range used to report results for all types of cameras.

 

Canon APS-C: The lens showed rather mixed image performance on an APS-C body. Center image resolution was top notch throughout the tested aperture range. Unfortunately, border image resolution was rather subpar - the lens was struggling here from wide open apertures all the way to f/11, with only marginal improvement in quality with stopped down aperture. Even at f/11, which is where the lens showed strongest border performance, quality is rather average. At its best, the lens would be capable of producing good quality 11in and OK 16in prints, which is rather weak (for a prime lens). Conclusion? With the rather subpar border performance throughout the aperture range, one will probably think that the production of this lens deserved to be canceled in favor of a more capable lens.

 

MTF50 (Line Width/Inch on the Print) @ 21mm
MTF50 (Line Width/Inch on the Print) @ 21mm

 

Normalized raw MTF50 @ 21mm
Normalized raw MTF50 @ 21mm

 

The lens showed mixed handling of chromatic aberration on an APS-C body. Center CA was quite minimal across the aperture range, ranging between 0.4px and 0.5px. However, border CA was significantly heavier, reaching 2px at f/4 but then dropping to about 1.7px by f/11. Disappointing needless to say.

 

Chromatic Aberration (APS-C) @ 21mm
Chromatic Aberration (APS-C) @ 21mm

 

Here are 100% crops, taken with an APS-C type camera, comparing image borders at f/4 and f/8.

 

Image borders @ 21mm (100% crop): f/4 vs f/8
Image borders @ 21mm (100% crop): f/4 vs f/8

Canon FF: Leica Super Angulon-R 21mm f/4 continued to produce exceptionally good results in the image center - you simply could not wish for a better quality, which remained consistently on a very high level throughout the aperture range. Regretfully, border performance also continued to underperform, and the image quality around corners was unimpressive at best. Well, considering that the lens did not show good border performance on an APS-C body, the underperformance on a FF camera does not really come as a surprise - really mixed performance with pretty drastic contrast in quality from center to extreme borders. Conclusion? Disappointing, considering such a stellar center resolving capabilities.

 

Normalized raw MTF50 @ 21mm
Normalized raw MTF50 @ 21mm

 

For a super wide angle lens, Leica Super Angulon-R 21mm f/4 showed moderate degree of barrel  distortion - at ~1.24%, distortion will be visible in certain types of shots, but generally speaking, is not that uncommon among such super wide angle lenses.

 

Distortion (FF) @ 21mm
Distortion (FF) @ 21mm

 

Chromatic aberration on a full frame body was as mixed as on an APS-C camera. Center CA was still under control, never exceeding 0.4px across the frame, but border CA averaged 1.4px and even was reaching 1.6px at f/4.

 

Chromatic Aberration (FF) @ 21mm
Chromatic Aberration (FF) @ 21mm

 

Here are 100% crops, taken with a full frame Canon 5D, comparing image borders at f/4 and f/8.

 

Image borders @ 21mm (100% crop): f/4 vs f/8
Image borders @ 21mm (100% crop): f/4 vs f/8

Alternatives

Leica used to offer a couple of wide angle lenses in its SLR lens lineup. Used to, because in March of 2009 Leica officially announced that it is discontinuing the R series cameras and lenses. The first one is Leica Elmarit-R 19mm f/2.8, although you should keep in mind that there are reports that the latest version of that lens hits the mirror of most full frame Canon cameras. The second choice is Leica Super Elmarit-R 15mm f/2.8 ASPH and its older, slower f/3.5 version. Outside of the Leica lineup, you might want to take a look at Contax branded Carl Zeiss Distagon T* 21mm f/2.8 or its newest edition Carl Zeiss Distagon T* 21mm f/2.8 ZF for Nikon F mount. Not really an alternative lens, but still worth exploring is Nikon's Nikkor 20mm f/3.5 Ai and its older versions Nikkor 20mm f/4 non AI. Finally, Olympus Zuiko OM 21mm f/2 and Olympus Zuiko OM 21mm f/3.5 lenses are two excellent lenses worth exploring.

 

Recommendation

Leica Super Angulon-R 21mm f/4 is a lens of contrasts (no pun indented). On the positive side, the lens produces some of the best in class resolution numbers in the image center and shows excellent color rendering throughout the aperture range. Distortion and vignetting are mild to moderate - quite tolerable for most photographers. On the not so positive note, border image quality leaves (a lot of) room for improvement and color fringing is 'rampaging wild' across all aperture settings (particularly around borders). So overall it is going to be a matter of preference for you, but you should keep in mind that there are a few other options out there that can deliver similar or even better performance (but maybe not at a better price).