The Sigma 50mm f/1.4 EX DG HSM is a professional-grade lens for enthusiasts and pros that need a high quality lens for portraiture and everyday photography. Its large aperture of f/1.4 is great for low-light photography and the shallow depth of field helps isolate subjects from the background, beautifully rendering background highlights, also known as bokeh. Unlike cheaper DX lenses, the Sigma 50mm f/1.4 is designed to work on both APS-C / DX and full-frame / FX sensors from many current DSLR manufacturers, including Nikon and Canon. The lens rivals other fast 50mm primes such as the Canon 50mm f/1.4 USM and Nikon 50mm f/1.4G and with a price point of around $500, it is one of the few third party lenses that is actually more expensive than branded versions. Is the Sigma 50mm f/1.4 better than other Nikon 50mm primes? How does it perform wide open and when stopped down? How does it handle? In this review, I will do my best to answer these and other questions you may have and will show you samples from the lens, with comparisons against the Nikon 50mm f/1.4G and the new Nikon 50mm f/1.8G lenses.
What does the Sigma 50mm f/1.4 offer to the already saturated market of excellent 50mm lenses from every DSLR manufacturer? For many years the focal length of 50mm lenses was considered a “standard” or “normal” focal length, because it closely resembles the perspective of the human eye. These lenses were widely popular on film cameras and the focal length was ideal for portraiture and everyday photography. As digital SLRs and zoom lenses started taking over the market, popularity of 50mm primes also decreased. The smaller size of APS-C sensors made the field of view of 50mm lenses narrower, while the flexibility of zoom lenses and their low price drove the demand towards convenience. Now that full frame digital cameras are getting more and more affordable, the once forgotten 50mm lenses are regaining their popularity among many photographers. Seeing this trend, some manufacturers including Nikon have been updating and renewing their 50mm lens lines. Sigma, being a third party lens manufacturer for many brands, introduced their flagship Sigma 50mm f/1.4 EX DG HSM in 2008 and has been marketing it as a higher-quality f/1.4 lens with better characteristics than most branded 50mm f/1.4 lenses.
What is so special about the Sigma 50mm f/1.4 lens? When compared to other 50mm lenses, it has some characteristics of high-end professional lenses. First, it is currently the only 50mm lens on the market with a massive 77mm filter size. Compare that to Nikon’s 50mm f/1.4G and f/1.8G lenses that have a 58mm filter thread. Even Canon’s expensive 50mm f/1.2L USM lens has a smaller 72mm filter thread. Second, it has an ultra-fast Hyper-Sonic Motor (HSM) that allows the lens to focus about twice faster than Nikon’s 50mm f/1.4G. Third, it is a large and heavy lens weighing 505 grams, which can help balance the lens with a DSLR body better. Fourth, the lens does not extend or rotate like some other 50mm prime lenses. And finally, the 9-blade diaphragm renders circular background highlights, which look more natural and pleasing than heptagon-shaped highlights on 7-blade diaphragm lenses. The Sigma 50mm f/1.4 EX DG HSM works and autofocuses on all new FX/DX and older Nikon DSLRs.
1) Lens Specifications
- Designed for use with full frame digital cameras. May also be used with smaller APS-c size sensors with a corresponding effective increase in focal length to about 90mm with most cameras
HSM (Hyper-Sonic Motor) ensures a quiet & high-speed auto focus
- Designed with molded glass aspherical lens elements for superior corrections of chromatic aberration & high image quality at all working distances
- HSM (Hyper-Sonic Motor) ensures a quiet & high-speed autofocus
- 9 blade diaphragm creates a pleasant out-of-focus- effect on backgrounds
- Mount Type: Sigma, Nikon, Canon, Sony, Pentax and Four Thirds
- Focal Length: 50mm
- Maximum Aperture: f/1.4
- Minimum Aperture: f/16
- Lens Construction: 8 Elements in 6 Groups
- Angle of View: 46.8º
- Number of Diaphragm Blades: 9
- Minimum Focusing Distance: 45cm/17.7in
- Filter Size (mm): 77
- Maximum Magnifications: 1:7.4
- Dimensions (Diameter x Length): 84.5×68.2mm/3.3×2.7in
- Weight: 505g/17.8oz.
- A lens hood, front & rear lens caps and carrying case are included with the lens
2) Lens Handling and Build
The Sigma 50mm f/1.4 EX DG HSM is built similar to current Nikon prime lenses – it has a solid plastic exterior and a metal mount. The lens feels very solid in hands and its large size and heavy weight make it feel like handling the Nikon 24mm f/1.4G. It is almost twice heavier than the Nikon 50mm f/1.8G, which is only 280 grams, and almost three times heavier than the Nikon 50mm f/1.8G (185 grams). The 77mm filter thread is a little too big for a 50mm lens in my opinion, because 77mm filters are expensive. Those who use 77mm filters like polarizing filter will probably be happy about not having to use a step-up ring, but such filters typically get rarely used on 50mm lenses in first place. There is, however, an advantage to having such large front element – as you will see in image samples below, it helps in reducing vignetting at large apertures. Here is how the Sigma compares to other Nikkor lenses (From left to right: Nikon 50mm f/1.8D, Nikon 50mm f/1.8G, Nikon 50mm f/1.4D, Nikon 50mm f/1.4G and Sigma 50mm f/1.4 EX DG HSM):
If you are used to Nikon’s focus ring, you might get disappointed by the fact that the focus ring on the Sigma is reversed. If you have to manually focus when shooting stills or video, keep this in mind. I personally prefer the focus ring on Nikon 50mm f/1.4G, because it felt softer and smoother than on Sigma; although, Sigma’s focus ring got much smoother after a week of moderate use. Shooting video with the Sigma was a little more convenient, because I could go from near focus to infinity very quickly without having to turn the focus ring multiple times. If you need precise focus, on the other hand, the Nikon 50mm would provide more accurate results. Going from autofocus to full manual focus can be achieved by switching from “AF” to “M” on the side of the lens or you can instantly override autofocus by manually turning the focus ring while in AF mode, similar to Nikon AF-S lenses. The Sigma 50mm f/1.4 comes with a petal type hood that stays securely locked once mounted on the front of the lens.
Just like the 50mm Nikkor lenses, the Sigma 50mm f/1.4 is not weather sealed. If you take a good care of the lens and use a protective filter in front of the lens, you should have no problems with using it in various weather conditions. Unfortunately, the lens does not come with a rubber gasket like the latest Nikkor lenses, so you have to watch out for dust between the lens and the camera mount or it will easily make it into the camera and the lens. Even the much cheaper Nikon 50mm f/1.8G is better protected against dust in this regard. As I explained in my “what to do with dust inside lenses” article, it is quite normal for lenses to suck air in and out when focusing or zooming in/out, so I recommend to try to keep the rear metal mount area clean at all times. Although the front part of the lens does not move when focusing, the front lens element does move in and out inside the lens barrel (just like Nikon 50mm f/1.4G and 50mm f/1.8G lenses). If you want to reduce the chances of dust and moisture making into the lens through the front of the lens, I would recommend to get a good 77mm clear/protective filter such as B+W 77mm F-Pro MRC clear filter and leave it on the lens at all times. Not only will it help protect the front element of the lens and reduce dust, but it will also make it much easier to clean the lens when needed.
3) Autofocus Performance and Accuracy
The Sigma 50mm f/1.4 autofocuses about the same as the Nikon 50mm f/1.8G and about twice faster than the Nikon 50mm f/1.4G. The autofocus accuracy of the Sigma 50mm f/1.4 is pretty good in both daylight and low-light situations, although it depends on whether the lens is properly calibrated or not. I ran a number of different AF accuracy tests with the LensAlign lens calibration tool and found the Sigma to be heavily front-focused. I had to use +10 AF adjust on my D700 and D3s cameras to be able to use the Sigma wide open at f/1.4. The bad news about front/back focus issues on most prime lenses, is that it is close to impossible to fully calibrate a lens with one AF adjust setting that works at all apertures. This happens due to problems with spherical aberration that can shift focus at different apertures. So I had to spend some time calibrating the lens at different apertures and distances to get results that were more or less acceptable for me. I personally get annoyed any time a lens has front/back focus issues like this. I do not understand why manufacturers cannot do more thorough QA tests before their products are shipped to retailers. We, as consumers, should be receiving properly calibrated lenses and cameras and not having to deal with testing our gear using focus charts. Unfortunately, these kinds of QA issues happen with all manufacturers, including Nikon. In my experience, however, Sigma lenses typically have more QA issues than Nikon, especially when it comes to focus accuracy. Here is a LensAlign test crop at f/1.4 after the +10 AF Adjust:
Before this calibration, the focus always landed between numbers 8 and 12 (2nd column from right) on the front. As with any other lens, be careful when shooting at very large apertures in low light situations. If you cannot consistently get accurate focus in daylight, your lens sample probably has a front/back focusing issue like explained above.
4) Lens sharpness, contrast and color rendition
As I reveal in my sharpness tests in the subsequent pages of this review, the performance of the Sigma 50mm f/1.4 is not that great when compared against Nikkor lenses, specifically at large apertures and in the corners. You can see many examples of lens sharpness taken in a controlled environment in the next page, along with comparisons against other lenses.
Bokeh is a very important characteristic of 50mm lenses. I would be ready to pay more for a lens that can yield better bokeh, even if it performed slightly worse than others at very large apertures.
Here is the full image from which I made the below bokeh crops:
You can see where I got the center and corner crops from. The corner crop is really not a corner, but rather an area taken from the left-center of the image. Let’s take a look at how the Sigma 50mm f/1.4 compares against Nikon f/1.4 lenses wide open at f/1.4 away from the center:
The Sigma definitely has the worst bokeh here; it looks as if the highlights were cut on their right side and the bokeh refractions, also known as “Onion Rings” or “Onion Bokeh” are too visible when compared to other lenses.
Now let’s take a look at the center:
The Sigma, once again, is performing worse in comparison – the bokeh reflections inside highlights are clearly visible. The Nikon 50mm f/1.4D looks the best in both crops with a clear bokeh and a more round oval shape. It is worth noting that the Nikon 50mm f/1.4D looks much different when stopped down beyond f/2.0 – its bokeh shape takes a form of a heptagon, due to the straight 7-blade diaphragm of the lens. When comparing bokeh at a range of apertures between f/1.4 and f/4.0, the Nikon 50mm f/1.4G overall gives the best bokeh. If you would like to see a comparison of these lenses with other Nikkor 50mm primes at f/1.8 and f/2.8, see my Nikon 50mm f/1.8G Review.
After I posted similar bokeh comparison results on the Nikon 50mm f/1.8G Review and criticized Sigma for having the worst bokeh, I received a number of emails from some angry Sigma 50mm f/1.4 owners – they all complained that my bokeh comparisons are not fair and only look at one side of bokeh with light highlights. Some of them specifically mentioned that they bought the Sigma 50mm f/1.4 lens because it yields better bokeh than Nikkors. I obviously could not leave the bokeh test incomplete and ran a number of other tests to see how the bokeh of Sigma looks in different environments, with subjects in front of and behind the focused area.
Here is another test I performed in an outdoor environment (resized full image, move over to see the Nikon 50mm f/1.4G):
As you can see, the edge of background highlights on the Nikon is more obvious than on the Sigma. Defined bokeh edge like this is a negative characteristic to bokeh quality, so the Sigma in this case clearly has a better bokeh. Here is how bokeh looks with both lenses stopped down to f/2.8:
Stopped down, the Nikon looks a little better with less defined image circles. This transition from bad to good on the Nikon happens at around the f/2.0 mark. If you are wondering why the image from Nikon 50mm looks more zoomed in than Sigma’s, that’s because Sigma’s focal length seems to be around 45mm instead of 50mm.
And to top this all bokeh comparison madness, here are two more tests – with focus behind and in front of the bokeh area. We’ll start with front:
And crops (mouse over to see the Nikon result):
Again, this test also shows that bokeh from the Sigma looks better when shot wide open and focused on the front area. Stopped down to f/2.0 and beyond, the Nikon 50mm shows more pleasant and less defined bokeh than the Sigma.
And crops (mouse over to see the Nikon result):
What a surprise – the Nikon looks much better than the Sigma wide open, when the out of focus area is in front of the focused area (focused behind). The highlights are less defined on the Nikon and look very pleasant, while the edges of highlights on the Sigma look very pronounced and thick, with some visible color fringing.
Conclusion: I probably spent way too much time doing bokeh comparison tests of these lenses. I just wanted to provide as much information as I could for those that are trying to decide which lens to get based on bokeh characteristics. As you can see from the above crops, Sigma only outperforms Nikon in one case – when shot at largest aperture of f/1.4 and the out of focus area is behind the subject. In every other case, bokeh on the Nikon 50mm f/1.4G still looks better, especially when stopped down to f/2.0 and beyond.
I hope these tests are comprehensive enough to all bokeh peepers out there. At the end of the day, these differences do not really matter, so I encourage my readers to take this all with a grain of salt…
Most prime lenses heavily vignette when shot wide open, especially on a full-frame body. The Sigma 50mm f/1.4 lens has a very large front element, which helps with reducing the effect of vignetting at large apertures. There is a moderate amount of vignetting at f/1.4, which is greatly reduced by f/2.0 and completely gone above f/2.8. Here are some vignetting samples at different apertures on FX:
Vignetting is very easy to fix in post-processing. Lightroom already has a built-in lens profile for the Sigma 50mm f/1.4 and enabling it under “Lens Corrections” removes any signs of vignetting, even at f/1.4.
When mounted on a DX camera, the amount of vignetting is much less pronounced, with only a slight darkening of the edges at maximum aperture:
The good news is that the Sigma 50mm f/1.4 is better at vignetting than any of the 50mm Nikkors. Here is a comparison against the Nikon 50mm f/1.4G:
The Nikon 50mm f/1.4G is significantly darker in the extreme corners and its vignetting is much more pronounced than on Sigma, all the way to f/2.8.
7) Ghosting and Flare
In most cases, the Sigma 50mm f/1.4 handles flares and ghosting well. When shot against the sun, with the sun in the corner, there is a single flare that shows up as a straight line with a couple of ghosts. Stopped down to f/8, the line becomes thinner, but more obvious. Compare that to Nikon 50mm f/1.4G, which has large green and blue flares. Here are some image samples at f/1.4 and f/8.0:
Note that the above were shot without a lens hood. If you keep the lens hood on the lens, you will get even better results when shooting against a bright source of light. Please note that the above images were taken without any filters. Using UV and other filters can potentially introduce more flares and ghosting to your images.
Here is a sample image shot at f/8, against the sun:
Similar to other 50mm lenses, the Sigma 50mm f/1.4 has a slight amount of barrel distortion when mounted on a full-frame camera. On DX, distortion is not noticeable and practically non-existent. As noted earlier, Lightroom already has a lens profile for the Sigma 50mm f/1.4 in the latest version (3.5), so you can easily take care of any distortion issues with a single click. Here is how the image looks like without any distortion corrections applied:
Note the curved lines on the top and on the bottom of the image.
9) Chromatic Aberration
Lateral chromatic aberration is very evident at large apertures, as shown on the next page. Stopped down to f/2.8 and smaller, CA disappears and is controlled well from that point on. Longitudinal chromatic aberration (which is the effect of color fringing in front of and behind the focused area) also does not look good. Take another look at the same LensAlign crop:
The above image was shot at f/1.4 and lit with 100 watt directional lamps. Unfortunately, stopping down the lens to f/1.8-f/2.0 still produces quite a bit of LoCA.
Let’s now move on to the good stuff – Sharpness tests. Select the next page below.
10) Sharpness Test
Some technical junk:
- White Balance: Auto, changed to “Custom”: 3200 Temp, +14 Tint in Lightroom
- ISO: 200
- EXIF information is preserved in the images
- Lens was mounted on Nikon D700 Camera and Gitzo tripod
- Focusing was performed through Live-View Contrast Detect
- Mirror Lock-Up mode with Exposure Delay set to “On” and remote cable release to completely eliminate camera shake
- Long exposure NR: Off
- Image Format: RAW
- Lightroom settings: Default settings
- Lightroom export: sRGB JPEG Quality 80
- Testing was performed at f/1.4, f/2.0, f/2.8, f/4.0, f/5.6 and f/8.0 apertures
- Nothing was moved during testing
11) Sharpness Test – Sigma 50mm f/1.4 Center Frame
The Sigma 50mm f/1.4 has good center sharpness, but with a heavy amount of purple fringing at largest apertures between f/1.4 and f/2.0:
Stopping down the lens to f/2.8 gets rid of the nasty fringing, but the image is still not as sharp at f/2.8. By f/4.0, however, sharpness improves dramatically:
The center sharpness does not change when the lens is stopped down to f/5.6 and f/8.0:
I am not including smaller apertures, because stopping down the lens beyond f/11 reduces image quality due to diffraction.
12) Sharpness Test – Sigma 50mm f/1.4 Corner Frame
The corner performance of the Sigma 50mm f/1.4 at largest apertures is quite poor. Wide open and at f/2.0, the lens yields soft corners as seen below:
Stopping down the lens to f/2.8 does not improve sharpness and by f/4 details start to clear up a little:
By f/5.6 the sharpness is greatly improved, but the peak performance is reached only by f/8.0:
To make the comparison more usable, I had to adjust the exposure of the first several crops in Lightroom (due to vignetting).
Overall, the sharpness results for the Sigma 50mm f/1.4 are disappointing, especially in the corners. See the next few pages for more detailed comparisons of the Sigma 50mm f/1.4 against other Nikkor lenses.
Compared to Nikon 50mm f/1.4G
The Nikon 50mm f/1.4G is currently Nikon’s fastest 50mm AF lens and it is a direct competitor to the Sigma 50mm f/1.4. Before I go over the test results, I would like to point out that the Sigma 50mm has a wider field of view compared to Nikon 50mm primes – equivalent to approximately 45mm in focal length. I had to move my setup about 6 inches closer to the target in order to get a similar field of view. Let’s take a look at how it performs against the Sigma at different apertures, both in the center and in corners.
13) Sigma 50mm f/1.4 vs Nikon 50mm f/1.4G Center Frame
14) Sigma 50mm f/1.4 vs Nikon 50mm f/1.4G Corner Frame
15) Sigma 50mm f/1.4 vs Nikon 50mm f/1.4G Vignetting and Distortion
As I have already shown on the first page of the review, the Sigma 50mm f/1.4 has less vignetting at small apertures due to its massive front element:
Distortion-wise, both lenses have a slight amount of barrel distortion on FX as noted on the first page of the review.
16) Sigma 50mm f/1.4 vs Nikon 50mm f/1.4G Conclusion
As you can see from the image samples above, the Sigma 50mm f/1.4 performs about the same in the center as the Nikon 50mm f/1.4G (minus the color fringing issues at large apertures). The corner performance, however, is quite poor in comparison. The Sigma has a hard time catching up with the Nikon and its corners get acceptably sharp only at f/8. Overall, the Nikon 50mm f/1.4G is clearly sharper. Both lenses have about the same amount of distortion, but the Sigma shines with lower levels of vignetting. It also handles flares and ghosting better than the Nikon both at large and smaller apertures. Lastly, the autofocus performance of the Sigma 50mm f/1.4 is about twice faster than that of the Nikon 50mm f/1.4G. I don’t know why Nikon decided to use a very slow AF motor on the 50mm f/1.4G – the new Nikon 50mm f/1.8G has a much faster AF-S motor. The area of debate is bokeh. As I have demonstrated on the first page of the review, Sigma produces better bokeh at f/1.4 when the out of focus area is behind the subject that is in focus. Stopped down and when focus is behind the bokeh area, the Nikon 50mm f/1.4G produces better bokeh. The same is true when background highlights are very bright – the Sigma seems to have more defined “Onion Rings”.
Taking all of the above into account (especially sharpness), the Nikon 50mm f/1.4G is overall a better lens, in my opinion. It is lighter, smaller and cheaper.
Compared to Nikon 50mm f/1.8G
As I have already shown in my Nikon 50mm f/1.8G Review, the new Nikon 50mm f/1.8G is a stellar performer. Below is a repost of the comparison.
17) Sigma f/1.4 vs Nikon 50mm f/1.8G Center Frame
18) Sigma f/1.4 vs Nikon 50mm f/1.8G Corner Frame
The corner performance of the Sigma f/1.4 is clearly its weakest point – it performed worse than all other Nikon primes, including the older Nikon 50mm f/1.8D.
19) Sigma f/1.4 vs Nikon 50mm f/1.8G Vignetting
As I have pointed out before, the Sigma’s strength is in the low amount of vignetting, largely due to the large front lens element and lens barrel. As you can see below, the vignetting levels wide open are like the Nikon 50mm f/1.8G stopped down to f/2.0. Sigma leads all other 50mm lenses in terms of vignetting here:
It is also worth noting that vignetting is even less pronounced on DX sensors – all of the above tests were performed on an FX sensor.
20) Sigma f/1.4 vs Nikon 50mm f/1.8G Distortion
21) Sigma f/1.4 vs Nikon 50mm f/1.8G Conclusion
The Sigma f/1.4 fails to deliver when compared to the new Nikon 50mm f/1.8G, which is even cheaper and lighter than the Nikon 50mm f/1.4G. Sharpness, CA/LoCA, flare/ghosting levels and bokeh are better on the Nikkor; distortion and AF speed is about the same. The only area that Sigma is better at is vignetting, which is easily correctable in post-processing software like Lightroom and Photoshop.
Summary and Image Samples
While being the largest, heaviest and the priciest of all 50mm lenses I have tested, The Sigma f/1.4 EX DG HSM simply fails to deliver. Its high levels of purple fringing and relatively low sharpness in the center frame are disappointing, while the corners are clearly the worst in the group. Longitudinal chromatic aberration levels are the highest as well, and as you have seen on the first page of this review, the rendering of bokeh is not great either, except when shot at f/1.4. In addition, the Sigma f/1.4 I tested was the only lens in the group that was heavily front-focused, which shows just how bad the QA of third party manufacturers can be. I would personally send it back to Sigma for readjustment and calibration right away, but I did not bother, since it was loaned to me for a month anyway. Sure, its vignetting level and AF performance (when properly calibrated) are impressive when compared against the slower Nikkor 50mm f/1.4G, but those are the only two positives I can think of. Considering the size and weight, it almost feels like an 85mm prime rather than a 50. Its corner sharpness looks better on a DX camera, but not by a huge margin.
Don’t waste your money on this lens – it is simply not worth the $500 Sigma is asking for. When compared to other 50mm lenses currently available on the market, the Sigma 50mm f/1.4 has the worst price-performance ratio. Even the much cheaper and lighter Nikon 50mm f/1.8G performs better in most tests in comparison.
22) Where to buy and availability
23) More Image Samples
EXIF data is embedded into all sample images.
All Images Copyright © Nasim Mansurov, All Rights Reserved. Copying or reproduction is not permitted without written permission from the author.