{"id":10049,"date":"2017-10-21T00:00:46","date_gmt":"2017-10-20T23:00:46","guid":{"rendered":"https:\/\/phillipreeve.net\/blog\/?p=10049"},"modified":"2024-04-21T14:19:45","modified_gmt":"2024-04-21T13:19:45","slug":"voigtlander-40mm-f1-2-nokton-aspherical-rolling-review","status":"publish","type":"post","link":"https:\/\/phillipreeve.net\/blog\/voigtlander-40mm-f1-2-nokton-aspherical-rolling-review\/","title":{"rendered":"Voigtlander 40mm f1.2 Nokton Aspherical: An In Depth Review"},"content":{"rendered":"

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Introduction<\/h3>\n

40mm. One of my favourite focal lengths. Long ago the Voigtl\u00e4nder 2\/40mm Ultron was glued to my Canon. Even longer ago, the Zuiko 2\/40 was a favourite on my Olmpus OM film gear. The 40mm equivalent 20mm Lumix was my favourite lens on the M43 gear I used to use for travel and hiking. So naturally a native 40mm full frame lens for E mount has me very excited.
\nThat slightly wider than standard lens look (close to the theoretical ‘normal’ focal length of 43mm) gives a lovely, natural perspective that leaves the photographer, rather than the angle of view, in charge of the image. But of course the cost of the slightly wider angle of view is less potential for bokeh; the nice, isolating, out-of-focus blur that people prize in people photography. That’s why the speed on this lens is potentially so great. Perhaps f1.2 sounds extreme, but the actual blur potential is about the same as f1.4 on a 50mm lens. So in order to keep up with a 50mm lens in terms of blur, you really do want a bit of extra speed on moderate wides. 40mm is a great length for portraits which place people in a context: but you don’t want that context to dominate, so being able to see the context but have it nicely blurred is a fantastic combination. But what price do we pay for that? Is the IQ on this surprisingly small and fast lens good enough?\u00a0Thanks to Mainline Photographics <\/a>\u00a0who are the Cosina Voigtl\u00e4nder distributors in Australia, for the loan of a review copy.<\/p>\n

A Few Samples\"\"<\/h3>\n

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Most of the samples in this review are viewable in high resolution at my SmugMug site<\/a><\/p>\n

Note on one sample: Note: much later a reader pointed out that the in focus area of the f1.2 image of the Bottlebrush (Callistemon\/Melaluca species, the red flower) seems to be sharper you would expect. I agree, and wonder if something has gone wrong here.<\/p>\n

Specifications<\/h1>\n\n\n\n\n\n\n\n\n\n\n
Max. Diameter<\/td>\n70.1 mm<\/td>\n<\/tr>\n
Length<\/td>\n59.3 mm<\/td>\n<\/tr>\n
Filter Thread<\/td>\n58 mm<\/td>\n<\/tr>\n
Weight<\/td>\nNominal 420 g \u00a0(weighed 416g without hood or caps)<\/td>\n<\/tr>\n
Max. Magnification<\/td>\n1:6.2<\/td>\n<\/tr>\n
Close Focusing Distance from the sensor<\/td>\n0.35 m<\/td>\n<\/tr>\n
Number of aperture blades<\/td>\n10<\/td>\n<\/tr>\n
Elements\/ Groups<\/td>\n8\/6, two double sided aspheres.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The lens is available now in Japan and Australia (in Australia from\u00a0Mainline Photographics<\/a>).<\/p>\n

Buy it from \u00a0from our affiliate link at CameraQuest<\/a>,<\/em>\u00a0B&H Photo Video<\/a>\u00a0or our link to\u00a0eBay.<\/a><\/p>\n

Buying through our links costs you no more, and makes a small contribution to running this blog.<\/p>\n

Handling<\/h3>\n

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The overall size is extraordinary for such a fast lens. You can see from the on-cmaera image that it is a nice match for the body, and the comparison photo below shows it considerably shorter than the classic Zuiko 1.2\/50 (itself by far the smallest classic f1.2 lens). \u00a0The slightly slower Sony Zeiss 1.4\/35 towers over it, and the considerably slower Loxia 2\/35 is a little less fat, but roughly the same length. This size factor is a very serious advantage for the lens: it means it’s not a special purpose ‘bokeh’ lens to be brought out when you want especially thin DOF, but something you can use as a genuine standard lens, your go-to walk around lens.<\/p>\n

The handling is gorgeous, if handling can be gorgeous. The focus ring is buttery smooth and responsive. It balances beautifully on the camera, being remarkably small and light for its size. There is a declicking ring should you wish to turn the aperture clicks off for video usage (like all the other E-mount Voigtl\u00e4nder lenses except the 65mm). The hood is small enough to leave on permanently, and if you do, the lens cap fits easily inside the hood.<\/p>\n

Infinity Resolution and Infinity Field Curvature<\/h3>\n

I start with an aperture series of a scene at infinity, with the lens focussed at the centre of the frame. Here is a complete frame to give a sense of where the 1:1 crops are taken from.<\/p>\n

The following set of crops show good but not outstanding results in the corners stopped down. The lens is however capable of excellent corner resolution, but it has some field curvature which needs to be accounted for, and yo have to take focus shift into consideration. I will show some crops illustrating this behaviour after the initial standard set of crops.<\/p>\n

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Focussed on Centre<\/strong>: At infinity, it is sharp centrally from wide open, though at f\/1.2 there is a lot of violet fringing from axial colour. This has cleaned up by f\/2, where the image is almost as sharp (very sharp) as it is going to get. When focussed on the centre, however mid frame, however, is a bit unsharp at infinity wide open, and still a little soft at f\/2, cleaning up at f \/2.8 and is excellent from f\/4. The corners, as we might expect, \u00a0are very soft at f\/1.2, pick up at f\/2.8 and continue sharpening up until being usable for landscape at f\/5.6 and fairly good by f\/8. This is of course not quite the kind of performance we have seen from the Apo-Lanthar, but nor should we expect it from a lens of this speed and dimension.
\nOverall the central and mid frame is outstanding stopped down a little, and the extreme corners are still decent. However the next set set of corps shows that excellent corner resolution is possible.<\/p>\n

Comparison of Corners, Focussed on Centre and Corners<\/strong><\/p>\n

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As you can see, the difference is quite significant.<\/p>\n

The corners are best somewhere very close to the infinity hard stop. The centre is best backed a little off the hard stop. The exact positions may vary from copy to copy with the calibration of the focus ring, but in general the corners are at best focus a little behind the centre.<\/p>\n

Focussing for the corners produces actually quite good results across the frame except for the centre. Focussing one the mid field will give excellent results over the whole field.<\/p>\n

Here are some centre crops, which show that focussing on the corners gives a strong blur wide open in the centre, but this is almost gone by f8 as DOF gets deeper.<\/p>\n

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It is notable that the corner focus setting gives a better centre stopped down, than centre focus gives a good corner. So stopped down, corner focus gives a better overall result. However at wider apertures, it seems that centre focus is better overall.<\/p>\n

A compromise focussing position will give you the best balance of sharpness across the frame. The next section will test whether there is such a compromise position.<\/p>\n

Best overall focus position for f8 and infinity<\/h5>\n

Now for a final piece of field curvature information: some crops of the corner and centre at f8 (where the curvature is already somewhat suppressed by DOF) focussed on the corner, outer midfield and centre. It shows that the midfield is a good compromise position.<\/p>\n

Not only is the midfield best when we focus on the outer midfield (obviously, which is why there is no crop) but while the corner is not quite as good as when focussed on the corner, it’s very good indeed when we focus on the outer midfield. The centre as well is, while not quite as good as the centre, also very good when we focus on the outer midfield. So the lens, with careful focussing, can produce very sharp results across the frame. These effects are visible at 100%, but are much less visible at 50%. So there is no need to panic. Especially if you have a 24MP sensor, where you probably don’t need to worry too much about where you focus at infinity.<\/p>\n

On my copy you can focus for excellent overall results at infinity by going to the hard stop, where you will get best corner results, and backing off the smallest amount possible, which will make the centre excellent without affecting the corners too much.<\/p>\n

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Focus Shift<\/h3>\n

These crops were shot at taking aperture.<\/p>\n

When processing the close focus samples later, I found that there is significant focus shift: stopped down images are noticeably sharper focussed at taking aperture than wide open<\/p>\n

Fred Miranda, over at FM forums has found the same at infinity: it’s well worth reading his finding and seeing his crops<\/a>, and I don’t see the need to repeat it here.<\/p>\n

The take home message is that this is a lens which needs ideally to be focussed at taking aperture. That’s a bit of a nuisance sometimes (as focussing wide open is easier, especially in low light). But it’s not that surprising or upsetting for a lens of this speed. Focussing at around f2.8 will actually get you most of the advantage of focussing at taking aperture if you are stopped down, and in dimmer light may well be the best option.<\/p>\n

Portrait Resolution (Or: Where Can I Put my Eye?)<\/h3>\n

A lens with these specification is surely in part an environmental portrait lens: otherwise the fastest apertures would be of little use, and certainly not worth the cost and weight.<\/p>\n

So how good a portrait can you take? I decided to take a series of portrait shots at f\/1.2 and f\/2.0 – likely the key environmental portrait apertures for this lens. In each of them the eye is progressively further off axis. Starting with the centre, moving to off centre to the centre side of the rule of thirds corner, then to the midfield just beyond the rule of thirds corner, and finally the extreme corner. The extreme corner would of course only contain the eye of your subject in a very inventive composition!<\/p>\n

First an image to show you the overall subject magnification (cropped a little horizontally, but showing the full vertical image field of view)<\/p>\n

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Centrally f\/1.2 is fine, and off centre it’s pretty good too. I can imagine using the outer midfield as well. At f\/2 the eye is excellent all the way to the outer midfield. A bit of sharpening improves this considerably. For those interested, f\/1.7 is pretty close to f\/2 in quality, f\/1.4 not much better than f\/1.2.<\/p>\n

Note<\/strong>: it looks as though the off centre f2 eye is a little less sharp than the outer midfield f2 eye. But this is a slight focussing error: looking more closely we can see that the iris has more detail in the off centre image at the expense of the lower eyelashes (which probably dominate the overall sense of sharpness) so it is focused a mm or so behind where the focus lies in the outer midfield image. So in reality it is a bit better than outer midfield, and really very good.<\/em><\/p>\n

Bokeh<\/h3>\n

Assessing bokeh is one of the most difficult things in a review. Some people give you crops of bokeh balls and elements of the OOF structure, but this in my view does not always give you a good idea of what the overall image is like. You can give aperture series, as I will here. But of course the look will vary a lot depending on the structures in the background, and on the distance from sensor to subject, and subject to background.<\/p>\n

The first series I offer has the subject\u2014these rather large flowers\u2014just under a metre away from the sensor, so it is the distance of a fairly close moderate-wide portrait. The rather messy kitchen behind is something of a torture test, and I’m very surprised how little structure and outlining there is, even at f1.2<\/p>\n