GAS warning! Do not let this lens grow on you …
A week ago, having finally gotten to terms with the fact I no longer owned an OTUS 85, I received this C-Sonnar 1.5/50 ZM lens from Zeiss. And what a joy that was: finally a lens I really didn’t like. Finally an opportunity to say something bad about Zeiss and not sound like the born-again fanboy.
Jewel lens
Out of the box, it looks drop-dead gorgeous. More jewelry than optical instrument, particularly with the lens hood attached. Perfect weight, perfect size, perfect looks. It matches the purposeful design of the Sony to a T. So unbearably Fab.
But on the camera, oh joy of joy … It. Was. Terrible.
Overly firm and gritty focusing, lack of contrast, overly long minimum focusing distance, poor corner compatibility with the A7r, dark and dull images. Review over, that was easy: Zeiss please remove this rubbish lens from your catalog, this is 2015.
Mood
I shared my concern with the French importer, who explained: this 1930’s design was updated in the early aughties but aesthetics have not been altered at all in the process. He told me how the design was similar to the crazy f/0.7 lens used by Stanley Kubrick to film Barry Lyndon and how CNES uses this lens in space.
His recommendation: Not your average look, not your average lens. Think it through.
I did. And there goes my reviewer’s neutrality cred, right out the window.
I’ll get to the real review shortly but, before that, let me explain what’s so interesting in this lens. My love for the OTUS came from the control that lens offers its owner over highlights and atmosphere. It’s nearly impossible to burn a highlight using an OTUS and I used my sample between +1 and +3 stop all the time. The 50/1.5 ZM is quite the opposite. It has a strong signature that can be hard to work around, burns anything vaguely bright faster than toast and focuses much more on mood than on perfection. It is both low(-ish) contrast and high in colours. And the natural tendency of the lens is to create slightly dark images. However, this needs to be qualified:
- Now that I’ve taken the time to make a few more photographs, it’s possible to alter the mood to light and airy, while retaining the soft natural rendering of the lens. I’m not sure about all photographers, but models are likely to prefer it to the ruthless OTUS.
Fresh
- The C-Sonnar absolutely shines in low-light. Unlike the night-owl OTUS that sees through the abyss and makes it look like daytime, the C-Sonnar creates low-light photographs that look like low-light, but with great clarity, colour and 3D. Really lovely stuff if that’s your style.
Dark
But I’ll get back to both points later. On with the formal review.
Ergonomics
Jewel-like build, good looks, 1/3 stop click aperture ring, a focus ring that smoothed out after a few hours … what more need I say ?
This is the result of many years of evolutionary design and it feels good in hand. For some reason, new designs such as the BATIS do away with essentials such as an aperture ring. Go figure.
3D and bokeh
Here’s a scene at f/1.5, f/2, f/2.8 and f/2.8.
3D is spectacular and subjectively feels better at wider apertures. Brilliant.
Swirly & bubbly bokeh is not my cup of tea, but it’s not too bad here. There are traces of agitation at wider apertures that get in the way of perfect smoothness, but it’s no big deal. Some actually prefer bokeh with a presence. What matters more is that this lens relays a lot of structural information in its out of focus areas, much like the Distagon 1.4/35 ZM and OTUS 55/1.4 but unlike the OTUS 85/1.4 and my Leica-R lenses.
My sincere apologies for now breaking the implicit code of lens reviewers by including cat pictures. But this one does illustrate the slightly bubbly nature of highlights that can often be objectionable and isn’t too bad here. f/1.4 at night. Again, note how soft this image looks but how clear and natural it appears in very low light.
As you can see in the chromatic aberration section enlargements below, f/2 is a lovely sweet spot (between aperture, aperture shape and correction), particularly for bokeh. f/1.5 displays some bubblyness, probably due to undercorrected optics. f/2 is very nice, with no bright outside edge to out of focus highlights.
From f/2.8 to f/5.6 the 10 iris blades draw dents in the otherwise perfect aperture circle, which appear in oof highlights (see below f/2.8). Avoid these apertures for pics in which highlight bokeh is really critical. Above and below these points, aperture is almost perfectly circular. Nice!
Silent race @f/1.4
But, even at f/1.4 the bubbly bokeh never intrudes when the background isn’t too crowded.
Chromatic aberration
These 100% enlargements speak for themselves.
At f/1.5, some chromatic aberration is present (top). It’s easy to correct and less than what the flagship Distagon 1.4/35 ZM exhibits at similar apertures (compare this in my review of the 1.4/35 ZM)
f/2.0 is excellent and a sweet spot for bokeh as well (middle).
Correction is almost perfect at f/2.8 (bottom).
Flare and glare
With the sun in the frame, there is very little trace of flare, even at f/1.5
Flare at f/1.5
f/1.5 uncorrected
f/5.6 uncorrected
f/5.6 is obviously better than f/1.5, showing better contrast and clarity. But the small flare at center is more visible and more difficult to suppress.
Note that these images are worst-case scenarios (sun flaring on a very dark foreground). Below are two real-life examples that show how good the performance really is.
Sharpness
A tricky one, sharpness. The lens isn’t designed for perfect corners at wide aperture, a fact compounded by the relative incompatibility with the A7r, and it shows abundantly.
Just kiddin’
At longer distances, you really need f/8 for a sharp photograph.
At closer range, this is one sweet lens in portrait scenarios or to enhance near-far relationships.
Atmosphere, Atmosphere
And what’s wrong with that ?
The best tools are those designed with a clear purpose in mind. A generic car isn’t designed for carrying many people, wading in the mud, screaming round a track, shining chrome at an exhibition or spinning doughnuts. That’s a utilitarian and boring car. A 67 L-88 Corvette is terrible off-road and no one would criticise it for it. A Porsche 918 won’t take your 4 kids to school in great comfort. And who would blame it for it? Both are fantastic cars in their own right.
Yet, it seems the consensus, when it comes to photographic lenses, is that they should perform flawlessly at every aperture in any conditions. Not so. The shortcomings in a lens can indicate poor design (as in too many cases) or a clear purpose.
It takes only a few seconds of looking at the C-Sonnar’s MTF curves to realise the use case for this lens is not ultimate corner sharpness at infinity.
(c) Zeiss. Click to access technical documentation
This is what Zeiss’s website says about the C-Sonnar : “The standard focal length offers special qualities, which make it well suited for portraiture and documenting authentic events and people.” Which makes sense, when you use the lens. It really is all about atmosphere and documenting mood and people.
So, it’s a specialized lens, in which corner sharpness doesn’t play a major role. That being said, it’s very decent closed down between f/2.8 and f/8. And pretty good, even at f/1.5 in the center. See photo below, and 100% enlargement.
Praying Mantis
Here’s a full-size image (at f/5.6) to download for pixel level inspection. You might recoil at what you see or be satisfied that, at 12″-16″ print size, it’s every bit as sharp as the FE55/1.8 (which has nowhere near as much character). Horses for courses …
King-size Cedar (click for 100% file)
Distortion
Distortion ? What distortion ?
Colour
Excellent. Lovely colours, although not quite as subtle as the Distagon 1.4/35 ZM, probably the world’s best in that respect.
The moody nature is evident and responds well to post-processing that enhances that feeling.
Hay Hay Hay
Porker pie
Fountain dew
The lens seems to express itself much better in low contrast situations, where it extracts every last drop of natural colour and reproduces it with an earthy pastel quality. More Gibson than Fender.
Here’s a variety of colours in gentle light.
Waiting
Red diagonal
Mauve at night
Attention
The C-Sonnar excels at creating somber atmospheres. If the Distagon 1.4/35 ZM is Mozart, then this is more Beethoven. Colours seem “dense”. Think of the density of Chateauneuf du Pape, of vinyl played through tubes and Spendor speakers, as opposed to rosé with ice cubes or YouTube played through earplugs, which is what you get with some lenses more focused on resolution.
Unfortunately, the C-Sonnar stumbles in bright, high-contrast scenes (see below). Highlights seem muted and unnatural in these conditions, so it’s best to underexpose and salvage shadows in post-processing.
High-contrast
With that in mind, it’s possible to work the image out of the somber-mood register, but it’s probably best to use the lens for what it does best: atmosphere.
Torn
Gold Vador
Bokeh bulb
Backstage
Greens
Place des Prêcheurs
Black and White
Provence, copping it again …
As I hope this photograph demonstrates, the C-Sonnar 1.5/50 ZM is a brilliant lens for black & white.
Brilliant, with minor reservations.
As discussed previously, the natural tendency to blow highlights means you’ll often be shooting at “darker settings” (less exposure) and adjustments in PP will become visible a that much earlier.
Compared to a no-compromise design such as an OTUS, the C-Sonnar offers less tone control. You’re left to play with a “smaller dynamic range”.
Still, the low contrast feel is again wonderfully atmospheric and, when the exposure range isn’t too wide, produces lovely tones. The photograph above is a perfect illustration. Just 3 roofs catching the evening light. The photograph in colour is totally uninteresting. Converted to B&W with little or no digital work added, it just sings Provence.
With a yellow filter on yellow flowers and a little clarity enhancement, it’s possible to make the look more modern and peppy. But the look remains natural and laid-back with no harshness anywhere.
So there you have it. Less incisive than the Distagon 1.4/35 ZM and less in control than the OTUS, it produces files that hint at Douasneau more than Adams. I feel that fits the marketing claims rather aptly.
Cloud slices
Quirks
Let’s see. Focus shift. It won’t bother you on a Sony A7x but will be a pain on rangefinder cameras (so much for the purity argument).
Blown highlights. This one puzzles me. The lens feels distinctly low-key, soft and low-contrast (in a good way) but acts high-contrast in that it blows highlights like a 1990’s digicam … See the tree trunks at bottom and sunlit walls in the fountain photograph above.
Focus breathing. It’s one of the more pronounced cases I have ever seen. Almost comical. For the price of a prime, you actually get yourself a zoom that breathes so much it seems alive. But that will only matter to videographers with no sense of humour 
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Weird bokeh artifacts. By the same principle that creates bubbles around out of focus highlights, f/1.4 can play strange tricks along contrast edges. In the second cat photo, above, my wife’s nose is literally cut in half by the bokeh if any contrast enhancement is added. Who does that to innocent women? A little more irksome, but entirely avoidable by aperture choice.
That’s about it and it matters little compared to what the lens does perfectly.
Conclusion
At the end of the day, this is a lens with a strong personality. Not really my style, but gorgeous nonetheless.
Last drops of light
I particularly love the way it clings to clarity and colour in low-light situations and makes them come alive.
My only real criticism is that controlling highlights is a real pain in some situations and photographs in high-contrast situations aren’t that great. Highlights, even when kept in check aren’t anywhere as beautiful as darker areas.
Also , in spite of the official claims to great bokeh, I don’t always enjoy it. Definitely not as obtrusive as others, it has a slightly gritty quality that occasionally spoils the ambiance that other aspects of the lens conspire so brilliantly to create.
Okay bokeh. Just Okay.
Apart from that (and the design that’s not all that happy on a Sony sensor) it’s all excellent news.
And, in spite of all that talk about darkness and strong personality, the C-Sonnar 1.5/50 isn’t a single trick pony. Close it down and you have yourself a very competent landscape lens. 
It’s also a beautifully designed lens, built like a little jewel that brings with it a strong and endearing personality (that tight focusing ring loosened up and became firm but silky smooth after a little while).
It’s a mature lens for a mature shooter. That is anyone taking the time to know the lens and learn to use what it does best and avoid the known idiosyncracies, and favours atmosphere over test results. Add points for M-camera owners. If that describes you, the C-Sonnar will put an endless smile on your face!
Posted on DearSusan by pascaljappy.