The Mighty Fifties – Zeiss 55mm f/1.8 vs Loxia 50mm f/2 vs Sigma 50mm f/1.4

The 50mm is not only nifty, it is mighty. It is a standard normal prime, meaning it gives a close approximation of our eyes’ field of view. This lens comparison will feature Disneyland, an $650,000 original Banksy piece, a beautiful model on a Malibu beach, a Shepard Fairey mural, and this peacock.

“Yippee ki yay.” Shot by a Loxia 50mm f/2.

The 50 is also the favorite focal length of the legendary street photographer Henri Cartier-Bresson. As he explained it when asked why the 50mm lens was his favorite,

“I worked with a 90. It cuts much of the foreground if you take a landscape . . .The 35 is splendid when needed, but extremely difficult to use if you want precision in composition. . . [the 50] corresponds to a certain vision and at the same time has enough depth of focus . . . .”

This comparo will again be broken into 5 rounds:

  1. Build quality
  2. Sharpness
  3. Vignetting and Flare
  4. Bokeh and 3D Pop
  5. Real World Handling

The Contenders & Their Specs

mighty nifty fifty lens comparison test
The Zeiss Sonnar 55mm f/1.8 (left); Zeiss Loxia 50mm f/2 Planar (center); Sigma 50mm f/1.4 Art with a Commlite autofocus EF to E adapter (right). Note: the Commlite adapter did not autofocus with the Sigma 50mm f/1.4. Only aperture and exposure could be controlled.

On the left, weighing in at a welterweight 281g with a $998 price tag (grey market $740), is the standard setting Zeiss Sonnar T* 55mm f/1.8. In the middle, weighing in at 320g with a $949 price tag, is the brand new Zeiss Loxia T* 50mm f/2 Planar. On the right, weighing in at a morbidly obese 810g with a $949 price tag, is the highly acclaimed Sigma 50mm f/1.4 Art DSLR lens,

Round 1: Build Quality (Loxia Wins)

Like the Loxia 35, the Loxia 50 also has an attractive blue O-ring at the lens mount to keep out dust and moisture. Kudos to putting thought into minor details.
Like the Loxia 35, the Loxia 50 also has an attractive blue O-ring at the lens mount to keep out dust and moisture. Kudos to putting thought into minor details.

In terms of build quality, all three lenses are in a league of their own. They are high-end lenses with prices to match and we shouldn’t expect anything less than rich materials, tight tolerances, and impeccable build qualities. Luckily, none of them disappoints.

zeiss 55mm f1.8 build quality
Notice the concave rather than convex front element.

The Sonnar 55mm has a beautifully minimalist design with nothing extraneous to ruin its simple cylindrical shape. The lettering on the lens is etched then filled in with white enamel. Its concave front element is unique to only a handful of lenses, including the Zeiss Ultron 50mm f/1.8 and the radioactive Canon FD 35mm f/2 S.S.C.

The focus ring is focus-by-wire, so it doesn’t actually turn any gears. In fact, there are no distance scales or any other depth-of-field markings of any sort. This may annoy some. I’m fine with it.

sigma 50mm f1.4 art build quality
Sigma Art’s matte plastics are soft to supple to touch, with none of the scratchiness or creakiness of older more cheaply made Sigma lenses.

The Sigma 50mm Art is the only plastic lens here. Metal lenses usually have a higher perceived quality but they also dent and chip more easily than plastic lenses. There is nothing wrong with plastic, especially when they are this high quality.

The focus ring has a very short and slightly scratchy throw, par for most modern AF lenses. The AF/MF button takes some force. It feel like your run-of-the-mill Canon L glass.

Most twist-on lens hoods have a plastic notch cut into the barrel that holds the hood in place after you rotate it past a certain point. Presuming that plastic can be worn down over time, Zeiss has replaced it with a tiny metal ball bearing. This is fastidious attention to detail.
Most twist-on lens hoods have a plastic notch cut into the barrel that holds the hood in place after you rotate it past a certain point. Presuming that plastic can be worn down over time, Zeiss has replaced it with a tiny metal ball bearing. This is fastidious attention to detail.

The Loxia 50mm is impeccably engineered and the manual aperture ring is a pure joy. Each “snick” of a 1/3 stop adjustment makes me feel that much more connected to my camera. It’s silly to say, but I look forward to mounting this lens on my camera because of this tactile sensation.

To pick between three closely matched contenders, the devil’s in the details. Each one is superbly built, but if I had to choose:

  1. Loxia 50mm – From the tactile aperture ring to the thick metal lens hood, there is simply nothing to complain about in terms of build quality.
  2. Sonnar 55mm  This lens feels like a masterclass in modern design; however, people will be divided over its aesthetics versus its lack of distance scale and depth-of-field markings.
  3. Sigma 50mm It feels like a reliable tool, but a tool nonetheless.

Round 2: Sharpness (Zeiss and Sigma Tie)

shepard fairey peace elephant west hollywood library
“Peace Elephant” by Shepard Fairey.

The 50mm normal prime is usually one of the sharpest in a lens range and these are premium offerings. Our test shot is the five storey tall mural by the renown artist Shepard Fairey. No boring test charts or dioramas here.

Procedurally, all test shots were taken with a Sony A7 with the lens focused to infinity. The Loxia was kindly provided by Zeiss USA and the Sigma was from Lensrentals.com. The camera was set to RAW with all autocorrections turned off. Images were processed via Lightroom without corrections or sharpening.

Click on the image for full resolution. Pay attention to the edges of the black "Obey" typography.
Click on the image for full resolution. Pay attention to the edges of the black “Obey” typography.

All three lenses’ center performances are brilliant wide open. This is especially impressive for the Sigma as it is a f/1.4. Contrast at the widest aperture is also excellent for all three lenses, with hardly a difference when you stop down.

Click on the image for full resolution. Pay attention to the "Andre the Giant" face within the star.
Click on the image for full resolution. Pay attention to the “Andre the Giant” face within the star.

The Sonnar’s corners narrowly edges out the Sigma when I pixel-peeped the RAW files at +200% zoom, but the Sigma was also more contrasty in the corners. Conversely, the Loxia shows some very minor softening at f/2.

There is really no sense in splitting hairs here because all three lenses are exceedingly sharp throughout the frame. DPreview lab test showed the Sonnar 55mm edges out the Sigma 50mm, but they were tested on different camera bodies (36MP Sony A7R and 22.3MP Canon 5D Mark III). DPreview have yet to test the Loxia 50mm. I’m going to call this a draw between the Sonnar and the Sigma.

  1. Sonnar 55mm & Sigma 50mm – Both are exceedingly sharp in the center wide open. Both are sharp in the corners wide open. The Sonnar is slightly sharper in the corners but the Sigma retains better contrast.
  2. Loxia 50mm – Very sharp in the center even when wide open. A very close second, marred by weaker corner performance.

Round 3: Vignetting & Flare (Loxia & Sigma Tie)

banksy parking girl on swing los angeles
“Girl on Swing” by Banksy.

In our recent Loxia 35mm review, we used the ceramic tiles lining the Space Shuttle in place of the boring “brick wall” vignetting test. This time, we are using a special white brick wall on a nondescript and run down building in downtown Los Angeles. On this brick wall, next to a busy sidewalk where pedestrians hardly stop to look up, is the image of a girl playing on a swing.

girl on swing banksy wide shot los angeles
Some say Los Angles is all glitz and glamour but no real culture. I’d say, there is more culture in a dirty parking lot here than in some curated galleries.

The girl is hanging from the “A” of a PARKING sign, with the “ING” whited out. She seems carefree and lackadaisical, as children playing often should. As I stood there to snap my pictures, rows of people walk by without acknowledging the significance of this little girl. One dignified looking silver-haired couple did stop and mentioned to each other, “That is a Banksy.”

girl on swing banksy close up los angeles
The stencil was recently placed behind plexiglass because it was vandalized with purple paint back in September 2014. The vandal was fined $13,000 in restoration costs.

That is a Banksy. For those uninitiated, Banksy is arguably the most significant artist alive today. Banksy is the pseudonym of an unknown street artist, known only by his satirical street art and political and social commentary through graffiti. Once written off as a vandal, he is credited for bringing street art and graffiti into the mainstream high art world. His works are sold and auctioned off, often without his permission, for hundreds of thousands of dollars.


Using the “Girl on Swing” as our backdrop, we noticed the Sonnar and the Sigma vignetted heavily wide open. This is not surprising for large aperture primes. The Loxia held its own right from f/2. The Sigma also recovered very nicely by f/2.

As for flaring or ghosting, I won’t bore you with a non-comparison of essentially three perfect examples of flare control. There was no flaring or ghosting issues with any of the lenses.

  1. Loxia 50mm & Sigma 50mm  The Loxia’s vignetting is very well controlled from wide open, but it is an f/2 lens after all. The Sigma heavily vignettes at f/1.4 but almost all of it is gone by f/2, which is equally amazing.
  2. Zeiss 55mm – Vignetting is the achilles heel of this stellar lens. Poor performance that doesn’t improve until f/5.6. Bummer.

Round 4: Bokeh and 3D Pop (Sonnar Wins)

There is just something about the Sonnar that makes you keep staring at the image. Even though it’s only a f/1.8, the way the in-focused subject pops out from the blurred background is unique to this lens and something I’ve not seen this side of a Leica manual prime.

Bokeh is naturally a hard thing to objectify and many often confuse quantity with quality. The myth is that the larger the aperture or the narrower the depth-of-field, the better the bokeh. If that is your belief, you can skip every discussion of bokeh in every lens review from now on and simply go for the widest available aperture lens. I hear you can rent Stanley Kubrick’s Zeiss 50mm f/0.7 nowadays.

Even at a deeper f/2, the Loxia produces some fantastic isolation with its bokeh performance. Cinematic is an apt adjective.

But from studying this aspect of photography over the years, bokeh is much more than just shallowness of depth-of-field. It’s the way the background blur is rendered AND it’s the way the blur interacts with the in-focus subject.

Loxia 50mm f/2, beautifully rendered bokeh while the in focus bits are very sharp.

In this arena, few lenses can compare to Zeiss. I have no specific brand loyalties. Nor are we paid to endorse one brand over another. But the fact of the matter is, there is a reason why it is called the Zeiss 3D pop.

Sigma 50mm @ f/1.4 shot at its minimum focusing distance. At close distances to the subject, faraway backgrounds are going to be blurred out completely.

I’ve already raved about the Sonnar’s beautiful bokeh and pop in the past, but what really surprised me this time was the Loxia 50mm. The general consensus online seems to be that Sonnar type lenses are thought to have the better bokeh, while Planar lenses can be a bit of a mixed bag. Well in this case, I think the two lenses are close in terms of bokeh performance. Very close.

Uh oh. I see some onion rings in Sonnar’s bokeh balls.

The Loxia is superior to the Sonnar in terms of its bokeh balls. If you compare the image above with the one below, the Sonnar’s have “onion rings” inside its bokeh balls due to its aspherical elements.

Loxia @ f/2. Please excuse the noise grain. This was taken at ISO 4000 cropped at 100%.

The Loxia’s planar design allows for superior performance without resorting to special elements. This results in clean bokeh balls with no dirty centers. However, after some back and forth, I still prefer the Sonnar’s bokeh and let me to tell you why.

Completely unprocessed image converted straight from RAW.

There is something magical about the Sonnar 55mm. Regardless of the distance between the camera and the subject, or the distance between the subject and her background, the Sonnar can isolate the focused and the unfocused so well.

A tighter crop of the image above. Notice the clean separation between the focused model and the unfocused background. The abrupt transition between the two is 3D pop.

Erwin Puts talks about this “abrupt transition” in detail in this technical article from Leica (page 10). He mentions that,

“A characteristic of current Leica M lenses is a visually faster transition from sharpness to unsharpness. This is helpful in composing the picture at full aperture, because pictorially important portions of the picture will stand out distinctly from the background.”

Zeiss Sonnar 55m f/1.8

The Loxia and the Sigma both have good bokeh but neither of them have that magical pop of the Sonnar. I could go on all day, posting example after example. Such is the nature of this subjective beast. I’m sure some will disagree with me, but having done my own blind tests, I’ve managed to pick out images taken with the Sonnar time after time. So, I definitely have a preference in this department.

  1. Sonnar 55mm – Very high bokeh performance with extraordinary 3D pop, despite onion rings inside bokeh balls.
  2. Loxia 50mm – Surprisingly beautiful and clean bokeh from a planar design. It certainly lives up to its Zeiss name but it couldn’t sway me from staring at the Sonnar images.
  3. Sigma 50mm – Good bokeh performance but quite ordinary at the same time, especially since it is a f/1.4. Sigma’s design priorities must be elsewhere.

Round 5: Real World Handling (Sonnar Wins)

disney california adventures paradise pier mickey mouse ferris wheel
The big Mickey Mouse ferris wheel at Disney’s California Adventures.

This final category, in my opinion, is one of the most important yet most overlooked aspects of lens ownership. Like automobile interiors, this is how you interact and spend your time with the product. As consumers, it doesn’t matter how well crafted a lens is if you don’t enjoy shooting it. You paid for it, you should enjoy it.

Buena Vista Blvd inside Disneyland California Adventures, meant to represent San Francisco’s trolley cars.

We took the lenses to the most difficult place we could think of for a real-world handling test. Since this is Los Angeles, our sidewalks aren’t exactly packed like in New York because everybody here is stuck in traffic. The most crowded place we could think of was Disneyland during spring break, so we went to Disneyland.

The Loxia extends every so slightly at its closest focusing distance, which by the way, is a very impressive 45cm.
The Loxia extends ever so slightly at its closest focusing distance, which by the way, is a very impressive 45cm.

For much of the afternoon, I had on the Loxia 50mm. I sometimes forgot it was a manual focus lens because it was easy to use. With a twist of the focus ring, the camera’s Focus Magnification feature is seamlessly engaged. There is no lag. There is no hesitation. Just twist, focus, and shoot.

Loxia 50mm f/2 @ f/8. The lens was extremely easy to focus since it automatically launches the Focus Magnification feature of the Sony A7 camera.
Loxia 50mm f/2 @ f/8. The lens was extremely easy to focus since it automatically launches the Focus Magnification feature of the Sony A7 camera.

For a moment, it makes my Sony A7 feel like a Leica rangefinder. I mentioned earlier about the “connectedness” I felt with the Loxia. It’s akin to driving a manual transmission sports car. The lazy will be turned off by it, but those who enjoy mechanical watches over quartz will prefer having full manual control.

Loxia 50mm @ f/8
Loxia 50mm @ f/8

One gripe I have about the Loxia 50mm and the Loxia 35mm is its infinity focus. Actual infinity is slightly before the infinity stop because of the lens design. This is bothersome because I can no longer “shoot from the hip” with the focus ring turned to infinity. I have to prefocus to infinity in my viewfinder and then hope I don’t touch the focus ring by accident. This was an inconvenience.

sigma 50mm is too big and heavy banana for scale
The Sigma is unnecessarily and unapologetically massive. Its size has no advantages other than as an expensive weapon against muggers. The banana is for scale.

For much of the evening, I had on the Sigma 50mm. It was entirely joyless to hold and shoot with, and it represents exactly what’s wrong with DSLR photography today. Instead of having something discrete and nonchalant, it was conspicuous and cumbersome.

There is nothing to complain about in regards to the Sigma’s image quality. Handling though, that’s another story.

The lens is way too heavy for street photography and it is much too long with the adapter and hood attached. Sigma sacrificed usability for absolute lab test performance. Optically, it is brilliant, but you wouldn’t want to take it out of your camera bag if you had one. I would much prefer this lens in a studio setting, on a tripod.


For rest of the night, I had on the Sonnar 55mm. This was a marriage made in heaven. The Sonnar is small, light weight, and optically excellent. It focuses quickly and quietly, with the minimum of fuss.

The Zeiss Sonnar is simply a joy to use.

There is nothing to complain about, perhaps other than the fact that it has a longer minimum focusing distance than the other two lenses (Sonnar at 0.5m, Loxia at 0.45m, and Sigma at 0.40m).

  1. Sonnar 55mm – The perfect balance of size, weight, and speed.
  2. Loxia 50mm – A manual focus lens that could give AF lenses a run for its money if not for its misleading infinity stop.
  3. Sigma 50mm  I will never let it weigh down my camera bag again.


2015-03-30 06.26.09 pm

When I was tallying up the results and making the chart above, I realized that each lens scored at least two wins. This didn’t surprise me because each one, in their own right, have their unique character and place on the market.

The Sigma 50mm f/1.4 Art is a recent breakthrough in the 50mm DSLR lens department, doing away with decades old design formulas that Canon and Nikon are so comfortable with sticking to. Optically, it is second to none. I can wholeheartedly recommend the Sigma 50mm to any studio photographer or professional with a crew, but I would not burden this lens on amateurs or prosumers. Sigma sacrificed weight and size for optical quality and in my opinion, it was not worth it for most of us. 810g is simply ridiculous for a 50mm lens. At $349, the classic Canon 50mm f/1.4 won’t break your bank or your back.

The brand new Zeiss Loxia T* 50mm f/2 Planar showcases an undeniable market and demand for premium manual focus primes. It is an improvement on the Zeiss ZE and the ZF because of its digital integration with Focus Magnification. This lens is what Leica should have done with its R-mount lineup. I suspect the only thing holding back the mainstream consumer is the manual focus. But don’t dismiss it until you’ve tried it. Rent one or buy one and take it for a spin. Maybe you won’t miss autofocus as much as you thought.

Lastly, I was really hoping one of these other lenses would usurp the Zeiss Sonnar 55mm f/1.8. But this mini-Otus was simply too balanced and too well thought out to be superseded here. This lens is a game changer. This lens will sway Canon 5D Mark III and Nikon D810 professionals away from their rich stable of cumbersome lenses. This lens proves that compactness, lightness, speed, and ultra-high optical quality, are not mutually exclusive.

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