ZM 50mm versus NEX 50mm by Björn Utpott.
Our reader Björn Utpott just sent me the link to his latest 50mm lens comparison (Click here to read it). The big question is: Is the new 50mm lens for NEX better than the “older” Zeiss ZM 50mm f/1.4 lens? The answer is pretty easy, the lenses have been designed for completely different kind if use. The Sonnar ZM has a more old creamy look with sharp center and less sharper borders. The new Sony 50mm is sharp through all the frame.
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Sony 50mm f/1.8 for NEX at
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Zeiss ZM Sonnar f/1.5 links at Amazon, B&H, Adorama, J&R, eBay
M to NEX mount adapter on eBay
Steve
2 years ago |I’ve noticed as I’ve moved from film to digital that lenses I believed to be sharp using film cameras turn out to be not so good on my 24mp a850.
SonyA77
2 years ago |Agreed, I’ve noticed the same on my 32mp NEX-7
zstan
2 years ago |trolling? o.o
Steve
2 years ago |I guess what I was trying say is that today’s high MP sensors can really challenge even the finest optics of only a few years ago.
Arthur
2 years ago |it is not the optics but coatings that are different. Most digital lenses were designed decades ago, and the only changes were better coatings and updated barrel looks. Sensor reflects light back to the lens because it is perfectly flat. Film is never flat and is also less reflective than sensor.
Solo
2 years ago |+1
Randy S.
2 years ago |Its called Halation. Its also not the problem. Every lens out there is designed for a given camera body. Its why a sigma tamron et al are seldom as good as the oem lenses. Comparing a lens that was designed with the intent of the light hitting the emulsion at an angle because the light passes through it. VS digital lenses that have a been designed to have the light all hit in parallel rays perpendicular to the sensor. So now you have this 50mm lens that is scimming the tops of the sensors microlens (which is why I own a Leaf digital back with NO MICROLENSes) and its being bent just like the way light is bent by the atmosphere. (well very similar) So that leitz lens is probably crazy sharp but not against a sensor it was never designed to work with. (keep in mind that lens was also design with a different size image circle thus increasing the angle at which the light is coming off the rear nodal point again something that wouldn’t matter with film.
Steve Jones
2 years ago |“creamy look” is a vague term which has no technical definition. The article is clear – the Carl Zeiss has field curvature meaning it won’t focus across a flat plane. I have my doubts that’s a design aim – I suspect it’s more likely to be a result of the state of art at the time the lens was designed with other compromises that had to be made.
In the old days of film, much of this would have gone unnoticed. Indeed, for very many photos the corners are of much lesser importance as that’s not where the main subject is. However, in these days when everybody can pixel-peep with digital sensors, such issues are ruthlessly exposed. However, I’m not sure field curvature can be described as a desirable feature.
Zino
2 years ago |I agree on the soft corners being more a limitation of technology available at a given time.
Nevertheless softer corners ar beautiful.
Robert
2 years ago |This lens was specifically designed to exhibit the “classic” characteristics of the sonnar design. The lens and its qualities are very well known in the rangefinder world. It is definitely a specialty lens, some people love it, others loath it. A “fair” comparison would be with the Zeiss Planar 50/2 ZM, which is a fully modern lens and by all accounts extremely sharp when used on the cameras it was designed for (i.e., Leica M mount rangefinders).
Not all “modern” lens are sharper than their antecedents. The Leica 50mm/2 Dual Range Summicron (from the 50s and early 60s) has been shown in some tests to have greater centre resolution than the modern version: indeed, under certain circumstances, it may be the sharpest 50mm lens ever made for the 35mm (and related digital) format.
Also, modern sensors do not yet out-resolve top quality lenses. Perhaps this is true of middling zooms (for example), but from what I have read, Nikon, Canon and Leica all claim that their pro lenses still out-resolve their highest resolution sensors, and will for some time to come.
Randy S.
2 years ago |The curve is on purpose actually for use when focused at infinity. Its not a flatfield lens. Its why some lenses have soft edges wide open. Because its physically impossible based on a given depth of focus(not DOF) to have a lens with a give angle of view be in focus at the middle and the edges when wide open. LIke if you shot a landscape wide open where everything is far away it would be in focus edge to edge but the closer you get and the more the edges will be out of focus. People are always seeing this as a negative but the result is many times because of how the lens we intended to be used. You would have the exact opposite problem using a macro lens (flat field) to shoot at long distance wide open. (or even medium distance.)
Björn Utpott
2 years ago |I wouldn’t describe field curvature as a desirable feature either. But there are times when it can be used to advantage.
Also, for those photos where field curvature would be a problem, I can always switch to another lens or another focal length. I got this lens specifically to complement my existing lenses; because it “draws” so differently. Personally, I like the look a lot, though that’s of course very subjective.
GH
2 years ago |I agree with your review. This lens is about subject isolation and vibe, and the high level of field curvature gives a great out of focus transition. I use the ZM 35/2 as my main lens on the 5N, but the 50/1.5 is fantastic for people shots, and it is very sharp if you focus into the corner.
c.d.embrey
2 years ago |The Zeiss ZM lenses were designed for Full Frame Film cameras, i.e. Leica and Zeiss range finder film cameras. The NEX line of cameras are 1/2 frame cameras (1.5 crop). I’d like to see some “brick wall shots” made with the FF Leica M9 to see just how soft the corners get when used as designed, i.e. for full frame.
For many older Nikon lenses the soft corners are not a problem because the corners are cropped out of the photo when used with DX (1.5 crop) cameras like the D7000 or D300s. Seems like this isn’t the case with the Zeiss ZM 50mm f/1.5.
Mike
2 years ago |Now I get it. If a lens is not sharp in the corners, it’s a crappy lens.
But if a Zeiss lens is not sharp in the corners, it was designed that way!
Kylberg
2 years ago |This is a good exaple of the “tyranny of measurements”: Modern lenses are designed to perform well in sharpness tests more than producing beautiful images.
It is easy to measure things like sharpness and noice and also to evaluate. On the web we pixel-peep and comments over this. I remember the times before MTF. At that time they representative photos and from that discussed the performance. At that time, sharpness was also important but there was a more holistic view on lens quality.
Today we see many not-so-expensive lenses that measures to be impessively sharp. They are – but images look flat, micro contrast is poor etc.
For instance i have an Olympus 45mm and an old Zeiss 50mm: The Oly is sharper but cannot compete with the Zeiss regarding color rendering and micro contrast. The Zeiss images are lots better.
Mike
2 years ago |And don’t forget psychology.
I bet, if you have two identical lenses, one with a Zeiss logo on it and the other with say a Walimex logo, and show the resulting pictures and the lens to – say – 100 people, there will be a significant bias towards Zeiss.
LEdgars
2 years ago |May be is some bias to justify price difference, but I tested myself and compared ZA to Sigma and difference is so much obvious.
Jean-Michel
2 years ago |+1. Let’s not forget that some Leica R lenses have been designed by Sigma in the past
Björn Utpott
2 years ago |I love the term you used: the “tyranny of measurements.” I guess I’ll have to subject all my lenses to a curved resolution chart to prove definitively that the Zeiss Sonnar 50/1.5 is the best
Can’t argue with facts.
Images from the Zeiss 50/1.5 also appear to have considerably better micro contrast than those produced by the Sony NEX 50/1.8. That’d be very tough to demonstrate conclusively though as there are so many variables. Even the actual focal lengths differ between the two lenses. But It’s very easy to tell which of the two lenses produced any given photo.
c.d.embrey
2 years ago |You can use the “defects” of soft corners and vignetting to help your photo. Framing your composition to make the “defects” a plus instead of a minus
and you can do it “in camera” instead of using PhotoShop 
The less time you spend in PhotoShop, the more time you have to shot photos 
Jack Le Boul
2 years ago |Good work Björn!
Vivek
2 years ago |ADMIN: It is a Sonnar (50/1.5) and not a Planar (50/1.4).
The ZM Sonnar isn’t even all that useful for the RF cams it was designed for. It has aperture induced focus shifts. I never understood the purpose of such lenses. Zeiss fans would defend it to no end though.
GH
2 years ago |I actually think the ZM Sonnar is more useful on NEX than on a RF. This lens is just about a portrait length on NEX, and the subject isolation is great with a unique bokeh rendering that you don’t get with the Planars. Plus, focus shift is negated with our live view NEX cameras.
The Sonnar is a fantastic lens for people shooting, with the unique look of the classic Sonnar, but updated with better contrast and less flare due to modern coatings. This is the lens to buy if you want a unique 50mm. If not, there are tons of 50s out there that all use the same basic double Gauss design.
Kylberg
2 years ago |Agree that not all Zeiss lenses are top quality; have a 300/4 that provides 600mm on my mFT camera. It is a lot better compared to Pana 100-300 @300 and also has a higher scale factor bringing you closer to the subject.
But the IQ is only great if all conditions are right.
The Pana weighs 50% and has OIS – guess which lens I bring most often..
(There are even Leica lenses that are average)
ihateidiots
2 years ago |Erm. The Zeiss Sonnar 50mm/f1.5 is a true blue Sonnar design, along with all its faults, including FOCUS SHIFT. But sonnar designs tend to be quite sharp when stopped down, especially at F8.