Zeiss Planar T* 1.4/50 ZF vs
Nikkor Ais 50/1.2
Review:http://www.martinzimelka.com/homepage/Blog/Blog.html

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Introduction:


So, why is a 50mm so important? The 50mm lens has been the traditional “standard” focal length of 35mm cameras for a very long time….well, up until recently when DSLRs came around, which mostly have APS-C sized sensors.  Many people regard the 50mm focal length to be one that closely matches the perspective of the human eye, which would make it seem more natural than other lenses. Most 50mm lenses are very high quality optics, light weight, small, and rather affordable.  The Zeiss 50/1.4 and Nikkor 50/1.2 are both exceptional quality optics, but they are not that cheap. They each have their flaws, and they each have their qualities.


The Nikon 50/1.2 has been regarded as a legendary lens by photographers, but it’s somewhat strange praise can be dismissed far too early by some. It’s a great lens, and I have worked hard at getting to know it – First impressions might disappoint some, as its flaws often show with bad technique and a lack of skill. Unfortunately many fast 50mm lenses suffer from a bad first impression by naïve and uninformed photographers. The Zeiss 50/1.4 is praised by some and dismissed by others. It has a reputation to have a harsh and nervous characteristic in out of focus areas, with a much too soft veil wide open - Don’t almost all fast 50mm lenses perform poorly in this area? Its hard to get an honest and objective review of this lens on the internet. Many people defend it absolutely, and others bash it as much as possible. What is the problem? Often one finds people having strong opinions on certain lenses even though they have never used them. I wouldn’t be too surprised if it turned out, that most of the bashers never owned/used this lens, and most of the crazy and defensive praisers can’t really justify their $ 725 purchase.


For quite some time, the Zeiss  Planar 50mm f/1.4 ZF has been the attention of my curiosity. I have always wanted one, probably for all the wrong reasons, and since owning the Nikon 50/1.2, I had no justifiable reason to get one. I wanted to know what all the fuss was about; What made this lens so great, but at the same time so “terrible.”

I finally came to the point of renting the Zeiss 50/1.4 for four days, so that I could compare it to my 50/1.2.





General impressions and opinions:


For starters, the Ais 50mm f/1.2 is built to give a very good impression of its quality and longevity. The focus is smooth, with a good amount of resistance. The Rubber on the focus ring is a  great nuance. The aperture ring clicks solidly into it’s single-stop positions. The black enamel paint seems tough, and all round it feels very well built with tight tolerances. Lastly, it looks really good, especially looking at it from the front, through it’s large optic.


The Zeiss shares many of the above qualities, except it doesn’t  have the same contours and lines as the Nikkor. The Zeiss looks like a simple lens. Its design is clean, simple and elegant. It’s black, with a chrome-plated brass front bayonet/filter thread, with numbers and markers coloured in red and white paint. The focus ring has a longer focus throw than the Nikkor, and it’s even more impressively smooth. In comparison, the Nikkor somehow just feels like a well greased helicoid compared to a magic and resistance free focus ring of the Zeiss - My Nikkor is virtually brand new, so it’s focus “feel” does not come from years of use. – Again, even being the cheapest Zeiss lens, the $700 Zeiss comes with its usually crappy lens cap, which falls off half the time and is very easily lost. It’s better left at home and replaced with a Nikon or other pinch cap. One thing that the Zeiss does come with, is a very cool metal bayonet hood, which clicks solidly into place. The $700 Nikkor doesn’t come with a hood, and even the optional hood has nothing on the Zeiss offering.


The Zeiss comes with a less popular filter thread size (58mm), but at least it shares this size with other Zeiss lenses in the ZF/ZE range. In terms of use and feel, I prefer the Zeiss. Compared to my Nikkor, its easier and lighter to focus with just one or two fingers. However, I’m not completely convinced of the focus ring texture. To me it feels slightly strange to the touch, and its not very grippy. It’s a difficult one, since rubber covered rings would NOT fit the look of the ZF range...




Imaging  characteristics:

(Please NOTE, unless otherwise stated, the opinions expressed are based on experience using a full frame digital camera)


The fist thing I noticed, when looking at the comparison shots, was that the Zeiss 50/1.4 had a higher contrast at apertures wider than f/2. This is a valuable character that earns the lens valuable points in my evaluation. Contrast, especially micro-contrast, give the impression of higher acutance/sharpness, and allows for less post processing at the end of the day.


The higher contrast of the Zeiss 50/1.4 probably contributes to emphasising it’s already harsh, hard-edged and nervous OOF (out-of-focus) rendering. While the hard edged background blur is annoying, it’s the copious amounts of transverse colour aberration in the OOF areas that make the blurred areas quite ugly. The blur discs don’t look pretty either! By design, most fast 50mm lenses share an optical design that is overcorrected for spherical aberration, which creates hard edged OOF areas, blur discs have a hard ring around them, and the background often shows the double line effect.


Unfortunately, at apertures wider than f/2, the Nikkor 50/1.2 has a very similar out of focus rendering to the Zeiss 50/1.4. It seems minutely less ugly though. The difference is so small that it’s not worth noting, and I would consider the two lenses equal in that department. However, at f/2, the Nikkor has a noticeably smoother rendering than the Zeiss. It just unfortunate that the straight edged 9 sided aperture starts showing its ugly head in the blur discs by f/2. The increased smoothness of the OOF rendering makes this not easily noticeable.


The above brings me to another pet peeve I have for some lenses…straight edged and non-circular aperture iris openings at wider apertures... While both the Nikkor and Zeiss have a 9 bladed aperture iris, those of the Nikkor are not rounded, therefore they do not have a circular iris opening at any aperture except f/1.2. Stopping down, the blur discs rendered with the Nikkor will look like a polygon rather than a circle. The Zeiss has rounded aperture blades, making wider apertures almost perfectly circular. This I regard to be quite a valuable character, however, Zeiss could have made a greater effort at keeping things round at apertures smaller than f/4.


Centre sharpness is a tricky topic, because with these kind of lenses, sharpness isn’t necessarily the most important aspect of a lens at wide apertures such as f/1.4. In general, the Zeiss does sometimes look sharper due to its better wide open contrast performance, but often it seems the Nikkor does render more detail. However, it’s on the D2x that one sees that they are pretty much on par wide open. The D2x has 50% higher resolving power than the D700, so with that I can’t conclude that the Nikkor seems sharper on the D700.  With regard to off-centre sharpness, the Nikkor 50/1.2 does a better job. It seems that the Zeiss’ sharpness falls off quicker towards the edges than the Nikkor. This is especially visible on the D2x, where the Nikkor is practically sharp from centre to edge by f/2, while the Zeiss lags behind. The testing for this was done on an infinity subject, so slight field curvature may have played a roll, however, I haven’t noticed in which direction.

[DX] On the D2x, the Nikkor and Zeiss are on par with centre sharpness when shooting wide open, ie f/1.2 vs 1.4. The Zeiss, having better contrast, looks better than the Nikkor image. When comparing both lenses at f/1.4, the Nikkor does have a tendency to show a fraction more detail at the centre, and even more so at the edges. At f/1.4 the Nikkor has a tendency to show a little more axial colour aberration. By f/2, the Nikkor is noticeably sharper at the centre, with a higher micro contrast, and this difference in detail becomes even more drastic at the far edges.


Both lenses suffer from axial colour aberrations. While the Nikkor might bloom more purple, that of the Zeiss looks more blue in colour. Purple, however, is easier to de-saturate without aversely affecting other colours, so its easier to reduce. Axial colour aberration affects contrast dramatically, and there isn’t a method to fix the contrast drop it causes. Its hard to determine why the Zeiss has better contrast, but I’m going to make a guess it’s due to the modern Zeiss T* coatings. The Nikkor design stems back to the early 80’s, so we are comparing lenses with differently aged optic coatings technology.


Unfortunately, the Nikkor vignettes quite heavily at f/1.2, and even at f/1.4 its still stronger than that of the Zeiss. This is not necessarily a bad thing, but it’s not good either. I certainly don’t like. If I were to increase the contrast of a Nikkor f/1.2 image with post processing, the vignetting would become even more pronounced. Since shots at f/1.2 or f/1.4 are fairly low contrast in general, the Zeiss would have a two point advantage… the Zeiss requires less contrast enhancement in post processing, and it has less vignetting to correct for also. While vignetting can be adjusted in post, it’s not ideal.


I have noticed other small differences between the two lenses. The Nikkor seems to have a shorter focal length than the Zeiss, but I’m not sure which one is closer to being a true 50mm. Zeiss specify the their lens is 51,7mm, so this makes it longer than 50mm...but is the Nikkor a perfect 50mm? Likely not. Another difference would be that the Zeiss renders a warmer image, one which is also a fraction brighter than that of the Nikkor at apertures f/2 and smaller. I’m not sure which lens has more accurate light transmission, as I cant test for t-stops. At wider apertures than f/2, the Nikkor seems brighter, but still somewhat cooler. Another subtle difference is that the Nikkor flares and ghosts easier than the Zeiss. This is probably due to deficiencies of the coatings in strong contra lighting, but its also due to a larger more protrusive front element. In comparison the Zeiss’ front element is more recessed and somewhat smaller in diameter. The fact that the Nikkor doesn’t get supplied with a hood, and the Zeiss does, doesn’t make it easier to prevent unwanted ghosts and flares when shooting is strong light.


For landscape work, I must admit, the Nikkor is better at wider apertures.

The Zeiss seems to reveal uneven sharpness at different parts of the frame. This is probably is due to field curvature, because it’s pretty symmetrical throughout the frame. The Nikkor, wide open at f/1.2, is on par for centre sharpness with the Ziess. At f/1.4 the Nikkor is a little better in detail and contrast, both at the centre and edges.

At f/2, the Nikkor has better detail and contrast, extending much further towards the edges than the Zeiss.

It’s only at f/2.8 and smaller that the two lenses start to match up, with a marginally higher micro contrast to the Nikkor.

Its only at the very extreme edge of the frame, that the Zeiss is sharper than the Nikkor from f/1.4 to just after f/5.6.

At the extreme edges the Zeiss has a tendency for detail to run outwards towards infinity, while the Nikkor seems to run more to wards the foreground. With settings set equal for both comparison shots, the look of the Zeiss is a little more desirable. The Nikkor would require a little post processing to match it.



Conclusion:


I find both lenses excellent, but neither are perfect. If you are shooting wide open, and have to use the 50mm focal length, then the slightly higher contrast Zeiss would be the better lens. If the rendering of OOF areas is important to you, then 50mm is not a good choice in focal length. With saying this, by f/2, the Nikkor renders the smoothest blur of the two lenses.

The Nikkor is shockingly sharp, and on a high resolution DX camera, you will soon notice how much the Nikkor has to give.

The Nikkor reaches it’s peak central performance by f/2, which extends very far towards the edges of the DX frame. This is quite something!


For me, I’m glad to be the owner of the Nikkor Ais 50/1.2. I envy the slightly better contrast of the Zeiss, but thats about all...

While I love my other Zeiss lenses, I cant say I’m as amazed by this Zeiss 50mm offering as I am with the other two (35/2 and 100/2).


For someone making a first 50/1.4 lens purchase, the Zeiss is an option one must weigh up carefully. For me owning two 50mm lenses, the Zeiss is definitely not worth the cost-benefit. The Zeiss is also quite a bit pricier than the Nikon AFS 50/1.4 or the Sigma 50/1.4. The latter being highly regarded for it’s very good OOF characteristics. 



Zeiss:


  1. Slightly better wide open contrast

  2. Warmer rendering

  3. Propensity to ghost and flare is less than Nikkor

  4. Vignetting less than Nikkor at f/1.4

  5. Edge performance lags behind for planar subjects up until f/2.8 for FX

  6. Edge performance lags behind quite dramatically for planar subjects  on DX

  7. OOF highlights hard edged and harsh from f/1.4 to f/2.8

  8. Well built

  9. Very smooth, easy to turn, with a longer throw focus ring

  10. Very good supplied metal hood

  11. Expensive new, and not that much cheaper second hand.





Nikkor:


  1. Slightly lower contrast

  2. Cooler rendering

  3. Propensity to ghost and flare is higher than the Zeiss

  4. Vignetting more than Zeiss even at f/1.4

  5. Better centre to edge performance for planar subjects from f/1.2 to f/2.8.

  6. Much better edge performance from f/1.4 onwards on DX

  7. OOF highlights hard edged and harsh from f/1.4 to f/2

  8. Well built

  9. Smooth, slightly stiffer to turn, with a longer throw focus ring

  10. No supplied hood.

  11. Expensive new, but much cheaper second hand.

NAVIGATION: