Sigma 50mm f/1.4 EX DG HSM

Gary Wolstenholme takes a look Sigma's first f/1.4 aperture standard lens, which sports a silent HSM focusing motor.

Sigma's 50mm f/1.4 EX DG HSM costs around £380 and sports a silent HSM focusing motor. This is the first time Sigma have attempted a lens of this type, and it has garnered quite a bit of interest as a result.

Canon users already have plenty of own-brand alternatives to choose from at this focal length. Whether it's the lowly and quite basic EF 50mm f/1.8 II, which costs around £90, or the EF 50mm f/1.4 USM, which costs around £290 and sports silent focusing just like the Sigma. Those with a taste for the exotic (and the wallet to match), may also be interested in Canon's top-line EF 50mm f/1.2L USM. This lens costs a whopping £1250, but for that you get one of the fastest production lenses currently available, weather sealed professional build and a silent USM focusing motor.

Nikon camera owners have only two 50mm lenses to choose from. Their 50mm f/1.8 AF-D costs around £105 but has the older screw-driven focusing system that isn't compatible with Nikon's latest entry-level bodies. Their direct equivalent to this Sigma is the AF-S 50mm f/1.4G, which costs around £295.

Pentax currently offer two lenses that would make a suitable alternative. Their SMC 50mm f/1.4 FA lens lacks silent focusing and costs £460. Their slightly more exotic SMC DA* 55mm f/1.4 SDM lens costs around £600 and has a silent focusing motor and weather sealed construction.

Sony users shooting with one of the crop-sensor Alpha SLRs have the budget DT 50mm f/1.8 SAM lens as an option. This optic costs around £150 and has a fairly basic, but lightweight design. A hangover from Sony's Minolta-flavoured past is the 50mm f/1.4 AF lens, which has screw-driven autofocus and costs around £325.

And finally, four-thirds standard camera owners looking to use a wide aperture 50mm as a 100mm equivalent telephoto have the Olympus Zuiko 50mm f/2 Macro as an option, which costs around £580.

As you can see, the Sigma isn't the cheapest 50mm f/1.4 available, but is still priced competitively, especially if you're a Pentax camera owner. With the lens being priced higher than the Nikon and Canon equivalents, I would hope that the lens shows characteristics that justify the extra expense.

Sigma 50mm f/1.4 EX DG HSM: Handling and features
The design of Sigma's 50mm f/1.4 is quite unique when compared to similar lenses. The lens is physically larger and noticeably heavier than equivalent lenses, due to the large diameter front element, which promises to provide more even illumination towards the edges of the frame. Also the filter size is 77mm, which will suit those who already have filters for a professional grade standard zoom lens.

Although this lens doesn't have an internal focus design, the movement of the optics is enclosed within the lens barrel, so the length of the lens doesn't change and the filter thread does not rotate. This will make the lens especially well suited for use with a polarising filter.

The look and feel of the lens is typical of their top-line EX range. The materials used feel like they can take a fair bit of use and abuse and the gold ring around the filter thread finishes off the look nicely. A textured powder coated finish has been applied to much of the exterior, which also looks very smart, but I find this finish can show marks easily.

As the lens has Sigma's silent HSM focusing motor, manual focus adjustments can be made at any time. The focus ring has a nice weight to it, making fine adjustments easy to achieve. Autofocus is performed quickly and accurately on the Nikon D700 used for testing, which is especially important when dealing with shallow depth of field at bright apertures.

Handling-wise, I really enjoyed using this optic. It feels every bit a premium product, although the extra weight and size can sometimes be as much a burden as a blessing at times.

Sigma 50mm f/1.4 EX DG HSM: Performance
Overall this optic proved itself capable of producing fantastic sharpness, especially in the centre of the image. Those after a technically perfect lens may be slightly disappointed with the performance towards the edges, but for portraiture at wide apertures, the high levels of centre sharpness should produce great results.

When shooting wide open images are reasonably sharp across the frame, although I have seen better from other similar lenses wide open. Stopping this optic down even a third of a stop causes a massive jump in centre sharpness. At f/2 the sharpness in the centre reaches excellent levels, but the quality towards the edges still lags behind somewhat.

Stopping the lens down continues to increase the sharpness in the centre to superb levels, but it isn't until f/5.6 that the quality towards the edges reaches good levels. Depending on your use for the lens, this isn't necessarily a bad thing. I tend to find the centre sharpness much more important for work at wider apertures.

Peak quality across the frame is achieved at f/11, where the sharpness across the frame is approaching superb levels. Even at f/16, the resolution recorded across the frame is more than excellent, making this a very versatile lens.

Resolution at 50mm

How to read our graphs The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column. The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple. For this review, the lens was tested on a Nikon D700 using Imatest.

Chromatic aberrations are at a low enough levels to not really be a cause for concern at every aperture. Even when printed very large the levels recorded by Imatest should not pose many, or any issues.

Chromatic Aberrations at 50mm

How to read out charts Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software. Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more. For this review, the lens was tested on a Nikon D700 using Imatest.

Sigma have made many claims about the peripheral brightness of this lens, and the results are technically better than what you would expect from a wide aperture lens such as this. At f/1.4 the comers are only 1.85stops darker than the image centre and illumination across the image area is visually uniform by f/2.8.

Barrel distortion is often present on wide aperture prime lenses like this, but the level this lens produces will be more noticeable than most. Imatest recorded 2.32% barrel distortion, which should pose any issues for most shooting scenarios, but may do so for more critical applications, such as copystand work. Luckily the distortion pattern is uniform across the frame, which should make it easy to correct in image editing software afterwards.

Click on the thumbnails for a high resolution image.
At smaller apertures, this lens is capable of producing images with superb resolution across the frame.		At wider apertures the centre sharness is very good and out of focus highlights are smoothly rendered.

Flare and ghosting were rarely an issue during testing, even when shooting into quite harsh light. A decent hood is supplied which does an excellent job of reducing flare caused by extraneous light.

DxOMark provides objective, independent, RAW-based image quality performance data for lenses and digital cameras to help you select the best equipment to meet your photographic needs. Visit the DxOMark website for tests performed on the Sigma 50mm f/1.4 EX DG HSM.

Sony DT 50mm f/1.8 SAM: Verdict
Sigma are clearly marketing this optic as a premium alternative to manufacturer's own lenses. In some respects the higher price is justified, but in others it is not. How you use the lens as well as the camera system you use will be the biggest factors in determining whether this lens is good value to you.

Without a doubt, this lens out performs some manufacturer's 50mm offerings, but not all of them. The sharpness in the centre is this lens' strong point, so if you tend to shoot at wide apertures this could be the lens for you. Pentax users after a bright 50mm should certainly consider this lens.

Sigma 50mm f1.4 EX DG HSM: Pros
Excellent sharpness in the centre at most apertures
Low vignetting
77mm filter size is the same as most professional level zooms

Sigma 50mm f1.4 EX DG HSM: Cons
Maybe a little softer than I'd hoped at f/1.4
Heavier than any other 50mm f1.4 lens
Bigger than any other 50mm f/1.4 lens

FEATURES
HANDLING
PERFORMANCE
VALUE FOR MONEY
OVERALL

Sigma 50mm f1.4 EX DG HSM: Lens specification

Price	£380.00
Contact	http://www.sigma-imaging-uk.com/
Filter size	77mm
Format	Full-frame
Construction	8 elements in 6 groups
Angle-of-view	46.8 degrees
35mm equivalent focal length (on APS-C body)	75mm
Internal focusing	No
Image stabilisation	No
Minimum focus	45cm
Maximum aperture	f/1.4
Minimum aperture	f/16
Weight	505g
Size	84.5mm x 68.2mm
In the box	Lens Hood Front and Rear Caps Fitted Padded Case Instruction Manual

The Sigma 50mm f1.4 EX DG HSM costs around £380 and is available from Warehouse Express here:

Sigma 50mm f1.4 EX DG HSM for Canon
Sigma 50mm f1.4 EX DG HSM for Nikon
Sigma 50mm f1.4 EX DG HSM for Pentax
Sigma 50mm f1.4 EX DG HSM for Sony
Sigma 50mm f1.4 EX DG HSM for Four Thirds
Sigma 50mm f1.4 EX DG HSM for Sigma

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