Voigtlander Nokton 50mm 1.2 Aspherical VM review
As soon as you start looking into fast prime lenses the temptation is always there. The fastest thing you can afford. Fast is sexy, exotic. Why settle for F2 when you can have that luscious F1.4? Hell, not even F1.4 is enough! What about F1.2? F1? Or the fabled, wild F0.95? The compulsion to get the most exotic lens never ends. In the film era it was for simple light gathering, because film wasn’t fast enough when light was fading. This is where the names Nokton and Noctilux come from: the suffix “noct” stands for night. But the faster the lens, the more compromises the lens designers had to make in the image quality department. Making an F2 lens is orders of magnitude simpler than F1.4. Adding even half a stop of light requires a lot more technology, glass and technical skill, not to mention adding size, weight and price. That’s why, traditionally, the Leica Summicron (which, in Leica lexicon, identifies an aperture of F2) has always been the lens with highest image quality. The Summilux (F1.4 usually) is more exotic, quite a bit more expensive, but it never reaches the levels of image quality across the frame that the Summicron does. At least, that has been the case for many decades, before the advent of reliable manufacturing of aspherical elements and much more advanced technologies in lens design and production.
With the advent of digital photography and the advancement in ISO capabilities of the sensors, the need for fast lenses for the sake of light gathering diminished. But a new fashion came, the bokeh mania. Now fast prime lenses found a new lease of life as bokeh machines. The faster the lens, the more blurred the background, the more bokeh to fawn over.
When I bought my first Leica M I was not immune to this fascination, and fast was what I wanted. Leica lenses were way out of my league price-wise, even more so the fast ones. Enter Voigtlander, with its Nokton line. The Nokton lenses range from F1.5 to F1.1 and are either 50mm or 35mm normally. Lately a Nokton 75mm 1.5 and Nokton 21mm 1.4 appeared as well.
The Voigtlander Nokton 50mm 1.2 Aspherical VM has been released in the second half of 2018. It was a really exciting lens for me because I had te Nokton 50mm 1.1 at the time and it was way too big for me. I still wanted a fast lens but the Nokton 50mm 1.5 VM was not an option as the only lens for two reasons, a good one and a stupid one: the good one was the ergonomics (see the review here) and the stupid one was that I wanted a faster lens! The Summilux 50mm 1.4 ASPH or pre-ASPH were not options because of price - I couldn’t justify paying that much for a lens at the time - and again not fast enough. The Nokton 50mm 1.2 promised to be even better quality than the Nokton 50mm 1.1 with almost the same speed and, most importantly, a much smaller size and weight. I bought it as soon as it was available. Was it worth it?
The handling
The Voigtlander Nokton 50mm 1.2 Aspherical VM is a beautiful lens. It is wonderfully built and a dream ergonomically. It feels solid and dense, with a weight of 347g. The sensation is of a really well put together lens, with tight tolerances and no play anywhere. It has 12 straight aperture blades moved by a fully knurled ring in half stop increments. The detents are clear and solid but the ring is buttery smooth to move, and it does stay in place in use without changing aperture inadvertently. It feels extremely refined and, in my opinion, no lens feels better in this detail. The focus ring is scalloped and knurled, with a perfect amount of resistance. From a purely haptic standpoint this lens is bliss. The only fly in the ointment is the width of it: albeit very short at 49mm, the Nokton 50mm 1.2 has a diameter of 63.3mm. It’s not very small, but it is small indeed for its speed. Overall the lens balances well, if a bit front heavy, on the camera. The optical design is a modified Double Gauss with 8 lenses in 6 groups, four aspherical surfaces and one anomalous partial dispersion lens. They went all out on aspherics!
A design choice that works perfectly for me is the bayonet mounted lens hood. Now, the lens does not come with one, and the genuine lens hoods cost a pretty penny. The LH-10 hood, designed for this lens, is ludicrously big. I have no idea why it has to be so monstrous. I am using the LH-8 lens hood, which already existed before this lens and was designed for the Nokton 35mm 1.2 II. A much better size and still offering good shading properties.
The large diameter causes minimal to moderate viewfinder blockage thanks to the very short barrel. The addition of the lens hood, though, will make the blockage moderate to severe at minimum focusing distance (MFD).
Overall for me the lens is a bit bigger than I would like but in use it just is a pleasure. The focus and aperture rings are well differentiated and you never get confused, focusing is a breeze and overall the lens gets out of the way to allow you to just shoot and create.
Image quality: sharpness
We will be analysing the same images shot for the 50mm lens comparison I published some weeks ago. For the sharpness at infinity this is the scene:
The images analysed will be 300% crops of the above scene. The crop is so extreme just to have the Windsor Castle fill the frame. From the image above we get the centre crops, then I reframed the scene to place the castle in mid-frame and finally in the far corner.
Here is a grid with all the crops in the analysis. Click on the image to open it in Flickr for a less compressed view.
Please keep in mind that we are analysing 300% crops: this is pixel-peeping, not photography. In real life to see this amount of detail in a print at 300dpi we would have an image measuring over 1.5m wide and 1m tall (or 60x40in)!
Centre:
Performance wide open is already very strong, with a detailed image that shows very low levels of uncorrected spherical aberration but not a very high level of contrast. At F1.4 we are only half a stop down, and the residual spherical aberration is already disappearing. Contrast has improved and it does so even more at F2, together with the details recorded. At F2.8 we are reaching very high quality levels, with plenty of micro-contrast now enriching the image: look at the subtle tonal transitions in the castle stonework.
There are traces of aliasing on the tower crenellations and the castle horizontal profiles on the smaller towers: that has nothing to do with the lens and all with the digital processing of the sensor: on the contrary, the lens is out-resolving the sensor and those profiles and details get rendered through guesswork by the digital algorithms. This is due to the fact that each pixel on the sensor can record a single colour, either green, red or blue. The algorithms will collate the data from neighbouring pixels to reconstruct an image as faithful as possible to the image projected on the sensor by the lens.
The Nokton 50mm 1.2 seems to have peaked at F2.8 and there is no further gain after that F-stop. To the contrary, F8 is definitely starting to show some diffraction degrading the sharpness.
Mid-frame:
We can detect a noticeable mid-frame dip in resolution: this is typical of aspherical designs and caused by their wavy field curvature. Wide open and at F1.4 the contrast is low and the detail not greatly defined (remember, we are at 300%!). At F2 we are starting to see a leap forward and at F4 the quality is really good. Peak performance for mid-frame is F5.6 and at F8 diffraction sets in again.
Corner:
The far corner certainly is not impressive at wider apertures from a purely objective (pun intended) point of view. Remember that this is a very compact F1.2 lens and the magnification is, again, 300%. There is an image in that corner from wide open and most detail is recorded, only masked by some residual spherical aberration but very little coma or astigmatism. Also, no chromatic aberration in sight throughout the aperture range: that is an exceptional performance! From the point of view of contrast and detail levels the Nokton 50mm 1.2 needs to be stopped down to F2.8 to get high definition and it peaks at F5.6 with very high image quality.
Overall The Voigtlander Nokton 50mm 1.2 Aspherical VM is a really high performance lens especially in the centre, but at F5.6 is exceptionally good across the frame, all the way into the extreme corner. Considering that this is an ultra-fast prime lens, this performance is lending it extremely good versatility.
Let’s have a look at all the test shots together at each aperture:
This should help seeing the progression from centre to corner at each aperture. I can’t stress enough the fact that these are 300% crops. Please put it into context. This lens is showing an exceptional performance in this test for such a fast prime lens. Also, if you shoot at infinity or higher distances it really makes no sense to shoot wider open unless it’s dark. The Nokton 50mm 1.2 simply delivers.
What if we rack the focus back to the opposite end? How does the Nokton 50mm 1.2 perform at close distance? Here is a series at minimum focusing distance (MFD) with a Leica M typ 240 battery as a subject. It measures 55x37mm. The MFD for this lens is the classic 0.7m of most modern rangefinder lenses. This might not sound impressive, but the lens is designed for the Leica M system and the rangefinder can’t collimate any closer than 0.7m.
Each shot has been carefully refocused using the electronic viewfinder (EVF). This is the setup, followed by 100% crops:
Wide open there is a visible glow from spherical aberration and quite some green-magenta longitudinal chromatic aberration (LoCA) on the edges of the label and on the symbols. The sharpness is not very high. At F1.4 there is a dramatic difference already with a lot less LoCA and higher contrast. much better again at F2 and it keeps on improving till it peaks at F5.6, with a really fantastic image rendering.
This lens is limited at close focus by the unavoidable spherical aberration inherent in optics. Spherical aberration is a lot more intrusive at close distance and can be corrected quite effectively with an independently moving optical group, called floating lens group/element (FLE), much like a zoom lens. The Nokton 50mm 1.2 has no FLE and it shows. If you want to see what an FLE construction can do look at the 50mm lens comparison here and look for the Leica Summilux 50mm 1.4 ASPH results. Or look at what a lens optimised for closer focus instead of infinity can do, like in the case of the TTArtisan 50mm 1.4 in the same comparison. But also look here how poorly the TTArtisan 50mm 1.4 does at infinity compared to the Nokton 50mm 1.2! Having said that, I reviewed the TTArtisan 50mm 1.4 here and never noticed the poorer infinity performance at all. That goes to show how those 300% crops for the infinity performance test have to be put into context!
Focus shift
Spherical aberration is also responsible for another unavoidable property of optical devices relying on spherical lenses: focus shift. To understand how that happens please refer to my article here. The same FLE design can really mitigate focus shift, as the Summilux 50mm 1.4 ASPH demonstrates here. How is the Voigtlander Nokton 50mm 1.2 Aspherical VM coping with focus shift?
Click on the grid for a less compressed version on Flickr.
The centre crops are the ones that will give us the clearest information about the focus shift behaviour of the Nokton 50mm 1.2:
Wide open the contrast and sharpness are, again, reduced by the spherical aberration. There is a healthy amount of spherochromatism that is clearly visible in these images until F4: green fringing of the defocused high contrast transitions behind the plane of focus, magenta in front. The contrast and detail improve at F1.4 already and the plane of focus hardly moves. At F2 the image quality improves a lot but the plane of focus is starting to move backwards, as expected. The target is still within the depth of field (DoF) and sharp. At F2.8 the overall image has improved but the target hasn’t sharpened up because it is now at the closer edge of the DoF. This robs it of finer detail but just. At F4 the DoF has reached backwards noticeably and the target is now comfortably within it, looking quite sharp and contrasty. At F5.6 and F8 the target is tack sharp and the DoF covers most of the calibration device. Even at its worst, F2.8, the plane of focus is no more than 2cm behind the target: this is a very good performance for such a fast lens with no FLE technology.
Mid-frame:
Apart from similar observations as in the centre crops for LoCA and spherical aberration, focus shift is not a factor here in mid-frame. The image improves from wide open all the way to F5.6 where it peaks.
Corner:
The plane of focus in the corner is closer to the camera: this demonstrates a positive Petzval field curvature at the outer image circle. Throughout the aperture range the sharpest area remains in front if the focusing target and is not influenced by focus shift. The very edge of the image, the lower right corner, becomes tack sharp at F8.
Overall the Voigtlander Nokton 50mm 1.2 Aspherical VM tames the focus shift issue enough to make it irrelevant in real life shooting.
Coma, astigmatism and sunstars
Another set of test shots straight from the 50mm lens comparison, but we can assess the single lens a lot better here:
The level of monochromatic aberrations for such a fast lens is ridiculously low. We can barely detect a tiny amount of sagittal astigmatism and some external coma with a LoCA green fringing. At F2 that disappears everywhere but in the extreme corner and a beautiful starburst pattern appears around the point highlights thanks to the straight bladed aperture mechanism design. At F4 the extreme corners are spotless as well.
Chromatic aberrations
Lateral and longitudinal chromatic aberrations (LaCA and LoCA) are the main types of aberration caused by diffraction of light through glass, much like the prism used by Newton (the Pink Floyd album cover as well!). Light splits in a rainbow colour and, in an optical device like a camera lens, it becomes really difficult to focus the different colours back in the same point on the sensor. In the case of LaCA the main colours (green, blue and red) will be focused on a different point, in LoCA the colours will be focused on different planes. A typical LoCA that we have already encountered is spherochromatism, seen in the focus shift tests and noticeable in the out of focus areas as green fringing behind the plane of focus, magenta in front. In the plane of focus it will be visible as green, magenta or red fringing on all sides of high contrast transitions. Another LoCA type is purple fringing (PF), which appears over the dark details in high contrast transitions and can be fairly obtrusive (look at the Nokton 50mm 1.5 review under chromatic aberration test). PF is caused by a secondary spectrum colour that is focused even closer than the primary ones. While an apochromatic design can attempt to focus the primary colours all in the same focal plane, PF is very hard to correct for but can be mitigated. LoCA will be brought under control by stopping down the lens. LaCA on the other hand can’t and it will be always present no matter the aperture. It can be generally seen as green-magenta or blue-yellow fringes around high contrast transitions and the same colour will be on the same side of the dark detail. It gets worse towards the outer image circle. A really good lens design can bring LaCA to very low levels.
We will analyse the centre and corner crops of a fence against a bright sky, which can give a very good idea about the aberration control of the Voigtlander Nokton 50mm 1.2 Aspherical VM.
Centre:
From wide open till F2 we can see quite some PF, but the most obtrusive aberration is not optical: it is digital PF. Look at that pinkish-purple fringing that is really noticeable on the edges of the fence rods: that is different than the purple colouring of the body of the fence rods. That is a digital artefact caused by light and electronic signal spilling into neighbouring pixels from the overly saturated ones in the high contrast transitions. PF and digital PF are degrading the image quite noticeably, but it is only partly the lens causing it. The digital PF is caused by the fact that those highlights are blown and oversaturated. My fault! Look at how the digital PF tends to disappear when some information creeps back in the highlights. From F4 the image becomes spotless.
Corner:
If we squint hard enough there is some green LoCA fringing and a trace of LaCA in the last few pixels in the form of blue-yellow fringing. The LaCA is irrelevant for any photographic purpose. The LoCA is mild and completely gone by F5.6. This is an exceptional performance.
Flare handling
The series is taken wide open to get the worst case scenarios. The source of light is a LED powerful torch, shone straight into the lens, then obliquely around 45 degrees, then at almost 90 degrees. I repeat: these are worst case scenarios!
The flare resistance is exceptional apart from two instances: straight on, light shining in the lens centre, and when the light source is hitting the lens elements obliquely from outside of the frame. This are weak points for any lens and will commonly create some blooming. Outstanding performance overall though: look at all the other images, especially with the light in the frame!
Vignetting and distortion
The Nokton 1.2 has a healthy amount of vignetting:
The vignetting never fully disappears but by F4 it is almost irrelevant. I think this is a trade-off for the very small size given the quality and speed of the optic. The colour signature of the Nokton 50mm 1.2 is slightly yellow/green but not cool. Each lens and glass/lens coating combination will give a colour signature to every lens. Have a look at the comparison grid for the vignetting and colour cast in the big 50mm comparison article to get an idea.
The Voigtlander Nokton 50mm 1.2 Aspherical VM has a mild/moderate pincushion distortion that can be corrected in Lightroom with a value of -3. Hardly a concern in everyday shooting but possibly noticeable with very straight lines.
Finally, the bokeh!
Of course we could not forget to analyse the bokeh rendition of he Nokton 50mm 1.2. Here are the images we will be looking at: click on the grid to open a larger version in Flickr.
The closer focus test shots will demonstrate the quality of the bokeh balls on the out of focus highlights (OOFH), the amount of cat’s eye bokeh (CEB) caused by mechanical vignetting and if there is any onion ring bokeh (ORB) that is typical of aspherical lenses. Chromatic aberrations and spherochromatism in particular will be visible if present.
Close focus:
The OOFH show no ORB but are not as clean as a purely spherical lens design: I think this might be due to a superimposition of the ORB of each spherical surface that eliminates the typical concentric pattern by interference and produces a more randomised irregularity inside the bokeh ball. I’m nitpicking here! There is minimal outlining of the OOFH but a green fringing from spherochromatism is definitely visible. and will be eliminated only stopping down to F4. The CEB is mild and irrelevant by F2. At F2.8 we can detect a faint blue and yellow fringe around the corner OOFH. Other than wide open the OOFH take on a dodecagonal shape due to the 12 straight aperture blades. By F5.6 the OOFH are starting to produce a sunburst for the same reason. Overall a beautiful bokeh rendition, with spherochromatism being the only drawback.
Focus at 3m:
Wonderful and smooth bokeh wide open. If you squint and press your nose against the screen you can see some spherochromatism, but it has no relevance in the image. At F1.4 it’s still wonderful, at F2 and F2.8 it gets less smooth because of the complexity of the background and a slight spherochromatic outlining of the OOFH. From F4 it gets neutral again.
Focus at 6m:
The OOFH are showing some outlining at this distance and the spherochromatism, apart from tinging the branches against the sky with green, is colouring the OOFH with purple inside. This is the same as the focus at 3m but more noticeable here, but also the same is happening to every single lens in the 50mm lens comparison here. The corners seem to be sharper than the centre, probably due to the mechanical vignetting and possibly some negative field curvature at further distance? As a result, the bokeh is a bit less smooth at this distance.
The bokeh performance is overall pretty spectacular, especially at close and medium distance.
Let’s take some portraits
I set up a studio-like kind of portrait with a light 45 degrees angle to the right and above the subject, my beautiful wife Daniela. There was a reflector on her left to lift the shadows. No rim light around the hair because I could not produce a decent one with my extremely limited lighting equipment.
Wide open the image is rich and defined but not blistering sharp due to the residual spherical aberration. Many people prefer to have a slightly less sharp lens wide open for portraits, for a gentler rendition of skin flaws. In this case the detail is there, but made slightly gentler. At F1.4 it has already sharpened up and at F2 it has a “sparkle”, the image is absolutely beautiful. The test is shot only up to F4 because the lens has already peaked at F2 and F2.8 for portrait applications. Really beautiful rendering.
Conclusions
The Voigtlander Nokton 50mm 1.2 Aspherical VM is a wonderful lens. If you are ok with the slightly bigger size you don’t need any other 50mm fast prime lenses in your bag. Leica or not.
PROS
Speed
Great handling
Performance at infinity
Very low focus shift
Minimal coma and astigmatism
Beautiful sunstars
Very well controlled chromatic aberrations
Spectacular flare control
Beautiful, soft bokeh
Excellent portrait lens
CONS
Maybe size but just
The Nokton 50mm 1.2 is an ultra-fast lens, albeit at the slower end of such category, and this kind of speed always comes at a cost. Each additional stop or half stop of speed poses enormous challenges for the designers of the lens.
What are the compromises for this lens? There are none, apparently. Which is quite amazing. The optical performance is incredibly high and well balanced, the size is just a tad bigger than average but still eminently portable and can easily be your everyday lens. The weight is only 12g more than the Leica Summilux-M 50mm 1.4 ASPH (black version). The only thing missing is a floating lens element (FLE) to optimise it for close focus and focus shift, but that would make it noticeably bigger and more pricey. Speaking of price, I think that £879 for an ultra-fast prime lens of this quality is a steal. Even more so in the Leica M system. What are you waiting for? Go get one!
I have used this lens for a lot of my shooting in the past and thoroughly enjoyed it. Here are a few image samples:
Please comment and let me know what you think!