Sigma 85mm f1.4 EX DG HSM Thomas, July 2012
 

Sigma AF 85mm f/1.4 EX DG HSM review

The Sigma AF 85mm f/1.4 EX DG HSM is a short telephoto lens with a bright f1.4 focal ratio. Announced February 2010, it's the only 85mm large aperture alternative to Nikon or Canon's own primes that offers auto-focus. The short telephoto lenses from Samyang and Zeiss are manual focus only. It is available for Canon, Nikon, Sigma, Sony, and Pentax mounts.

Sigma has priced its 85mm f1.4 lens in-between the budget and high-end 85mm options from both Canon and Nikon. So it's more expensive than the Canon and Nikon f1.8 models, but comfortably cheaper than the Canon f1.2 and Nikon f1.4 versions. As such anyone considering buying either of the big-brand options will naturally be wondering how the Sigma compares.

On both cropped and full-frame bodies the 85mm focal length is considered a preferred candidate for portrait-photography as it gives you some distance from your subject which leads to a flattering perspective. This, combined with the capability to render blurred backgrounds with a smooth bokeh, makes large aperture 85mm lenses very sought after. Another use-case for 85mm primes is street-photography where you need some reach and a fast shutter speed. But 85mm lenses may also be used for nature photography and capturing landscapes.

In this review I've taken a detailed look at Sigma's 85mm f1.4 prime to find out whether it can deliver the goods. To really push it to the limits I tested the Nikon F-mount version with a 36 Megapixel full-frame Nikon D800, although my results and conclusions are equally applicable to other mounts and systems.

   
   


Facts from the catalog

Here's the usual look at the technical data first with some comparison to its prime competitor for Nikon DSLRs, the Nikon AF-S 85mm f1.4G. I've rated the features with a [+] (or [++]), when it's better than average or even state of the art, a [0] if it's standard or just average, and [-] if there's a disadvantage.

   
 
   
   

Size (diam. x length): 85 x 88 mm (3.3 x 3.5 in.). This is not a small lens, but of similar size to the Nikon equivalent. It still fits harmoniously on a larger APS-C or FF-/FX-body. [0]

Weight: 719 g (25.4 oz) = 124 grams heavier than Nikon's. [0]

Optics: 11 elements in 8 groups vs. 10 elements in 9 groups on Nikon's 85/1.4G. This is still a small amount of glass compared to zooms that tend to have something like 21/16. That bodes well for contrast and flare-resistance. Sigma used two special glass-elements in this construction. [0]

Closest focus distance/max. magnification: 0.85 m (2.8 ft.) / 1:8.6. This does not come close to what I often need in nature (1:3-1:5). So no honorable mention for this performance, but other 85mm lenses don't focus closer either. When using a 2 diopter close-up filter (like the very good Canon 500D) you could reach a magnification around and beyond 1:5.8. [0]

Filter-thread: 77mm = standard with larger pro-lenses [+]

IS: No = a pity! Many zooms covering 85mm as well as the Sigma 105/2.8 macro lens have OS. You can only hope that with a 2 stops larger aperture you could crank up the shutter speed to where shake is less likely. And shake you see: Just look through the viewfinder! [--]

AF: AF with HSM (hyper sonic motor), so it does work on D60/3x00/5x00-bodies or Canon bodies w/o AF-motor, manual-focus override by turning the focus ring [+]

Covers full frame/FX or smaller = very good [+]

Comes with a nice soft-case that protects the lens better against banging around than the flimsy pouches that Nikon supplies. [+]

Price: around 860 EUR new (incl. 19% VAT) = much cheaper than Nikon's 85/1.4G at around 1400 EUR. Canon's EF 85mm 1.2 II L USM is around 1900 EUR but offers 1/3 of a stop larger aperture. [0]

The lens-caps are almost like standard Nikon's but the rear cap still can only be screwed on in exactly one position - not three like with Nikon's. [0] Lens-shade included and reversible for transport plus there is a APS-C/DX hood-extender that adds 3.5 cm to the hood for extra protection against light. [+]

Distance information is relayed to the camera, so the Nikon body can do all the advanced exposure-related stuff with this lens. But this is true for all the alternatives too. [+]

Aperture ring = no, just like all modern lenses. [0]

Sealing: no. [0]

So the score in the "features-department" is 2[-]/8[0]/6[+].

 

Motivation:

Large aperture 85mm lenses are for isolating your subject from some distance and/or getting faster shutter speeds when your subjects are moving. But I can use this as a nature shooter too because I love not having everything in equal sharpness.

Alternatives:

For getting at least f1.4 at 85mm there are really only four alternatives for Nikon users (and 3 for Canon users). But only 2 (resp. 1) offer AF:
- The old Nikkor AF 85/1.4D, can still be had, just a little more expensive, but supplanted by...
- The new Nikkor AF-S 85/1.4G which is much more expensive but provides excellent performance (see my Nikon AF-S 85/1.4G review)
- The Zeiss ZF.2 Planar T* 85mm 1.4 (manual focus only)
- The Samyang AE 85mm 1.4 Asph IF (manual focus only)
- The Canon EF 85mm 1.2 II L USM, which offers 1/3 of a stop larger aperture at more than double the price.
Or you go for the cheaper f1.8 lenses from Nikon (see my review of the excellent Nikon AF-S 85/1.8G) or Canon.

Testing: Longitudinal Chromatic Aberration

With large aperture primes one of the first tests I perform is for longitudinal CA (loCA, a.k.a. "axial color" or "bokeh CA") and it normally shows some pretty nasty coloration unless you have a very expensive apochromatic lens. The Sigma 85/1.4 is no exception and shows quite some amount of loCA as the following image reveals.

 
Sigma AF 85mm f/1.4 EX at f1.4 Longitudinal Chromatic Aberration (loCA)
100% crop, f1.4, left=closer, right=farther away

 

The effect looks pretty bad here, and it is not fully gone at f5.6. But you can eliminate the effect pretty easily in CaptureNX 2 or with the new tools in Lightroom 4.1.

The acid test is shooting trees against a glaring sky. In the case of the Sigma that does produce only a small amount of ghostlike magenta twigs. But that depends on AF Fine Tune: If I had focused just a tad closer the magenta CAs would have gone away completely.

Chromatic Aberration test: shot with Sigma AF 85/1.4 EX @f1.4 on a D800
f1.4, 100 ISO
 
   
f1.4, 100 ISO
 
f1.4, 100 ISO
  f1.4, 100 ISO

 

Sharpness and contrast

Let's have a look at the theoretical performance (MTF-charts) of the Sigma lens and its competitor from Nikon first:

 
85mm f/1.4 MTF at f1.4
The Sigma AF 85/1.4 EX DG HSM
  Its competitor from Nikon, the AF-S 85/1.4G

   

These charts show the lens-performance at the largest aperture, in this case for f1.4. To read these charts you only have to understand that higher values are better and that the closer the dotted and the continuous lines of each color are together the less astigmatism (= resolution depends on the orientation of the test-pattern) the lens has. The x-axis displays the distance from the optical axis (=center of the sensor) in mm. I'll show you the real-life performance at 4 mm (center), 13 mm (DX-corner), and 20 mm (FX-corner) on a D800.

From the charts the Sigma should perform similarly to the Nikkor. But Sigma's design has a little problem with astigmatism at sagittal structures (S10) from 15 mm onwards. But let's see how this theoretical performance translates into real life results in the sharpness test based on Siemens-stars.

I present near-center results (first column) followed by DX-corner results and FX-corner results on a D800. The results shown here should also be a very good approximation for performance on a 16MP DX/APS-C sensor. Just keep in mind that these results are not directly comparable to my previous reviews on a D300 and D700.

Processing was done in Lightroom 4 from RAW at camera standard settings. Noise-reduction is set to 0, sharpening to 70/0.5/36/10, with no extra tone, color, or saturation adjustment. White-balance was adjusted to a neutral white and I did some exposure compensation to make the brightness match. CA-removal is ON. Focus was achieved in live-view with some fine-tuning by hand and is optimized for different apertures in the FX-corner shots to get optimal sharpness. This unfortunately is something you would not achieve with simply using contrast- or phase-shift-based AF. More on this later.

These are all 100% crops!

 

Sigma AF 85mm f/1.4 EX with Nikon D800
100% crop from center
Sigma AF 85mm f/1.4 EX with Nikon D800
100% crop from DX-corner
Sigma AF 85mm f/1.4 EX with Nikon D800
100% crop from FX-corner
   
f1.4, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
         
   
f2.0, 100 ISO
f2.0, 100 ISO
f2.0, 100 ISO
         
   
f2.8, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
         
   
f4.0, 100 ISO
f4.0, 100 ISO
f4.0, 100 ISO
         
   
f5.6, 100 ISO
f5.6, 100 ISO
f5.6, 100 ISO
         
   
f8, 100 ISO
f8, 100 ISO
f8, 100 ISO

 

The Sigma produces very high resolution in the FX-corner wide open - but at the cost of low edge-contrast. A bad case of spherical aberrations / coma which also fooled the contrast-based AF of the D800: The camera chose a focus where the aberrations were lower and thus the contrast better - but at the price of sharpness. For the table above I corrected this by manually focusing considerably farther away than the AF suggested. Mind you, I even had to use different focus-corrections depending on the aperture.

The following row shows the FX-corner of the Sigma 85/1.4 when relying on the contrast-AF system of the D800 alone. This is what you'd get when the camera is aiming for the highest contrast, and as you can see it comes at the cost of sharpness.

Sigma AF 85mm f/1.4 EX
with Nikon D800
100% crop from FX-corner

Sigma AF 85mm f/1.4 EX
with Nikon D800
100% crop from FX-corner
Sigma AF 85mm f/1.4 EX
with Nikon D800
100% crop from FX-corner
   
f1.4, 100 ISO
f2.0, 100 ISO
f2.8, 100 ISO

This shows much less definition at thin lines than the crops I presented in the large table. But edge-contrast is much better.

The following row shows the FX-corner of the Sigma 85/1.4 with contrast-based AF on the center of the test-target:

Sigma AF 85mm f/1.4 EX
with Nikon D800
100% crop from FX-corner

Sigma AF 85mm f/1.4 EX
with Nikon D800
100% crop from FX-corner
Sigma AF 85mm f/1.4 EX
with Nikon D800
100% crop from FX-corner
   
f1.4, 100 ISO
f2.0, 100 ISO
f2.8, 100 ISO

This produces results that have better sharpness but with the effects of spherical aberrations / coma not as pronounced as in the long table earlier.

These 100% crops directly from a 36MP D800 sensor are proof that this lens can produce astonishingly sharp images. Even wide open, the center resolution is very high. Deterioration of image-quality in the FX-corner is mostly regarding overall contrast, but sharpness and definition is still very good. Stopping down to f2.0 does improve performance at the center and the DX-corner a bit. f2.8 almost eliminates the spherical aberrations at the DX-corner, and at f4.0 they are gone. But you need to stop down to f5.6 to get the FX-corner to sharpen up considerably with f8 improving the performance even further. So for highest contrast and sharpness in the FX-corner you need to stop down pretty far. Of course if your subjects are portraits where the detail tends to be towards the middle of the frame and not in the corners, it's hardly an issue, but those who intend to shoot landscapes or architecture will want to know how it performs right into the corners.

 

Sagittal coma flare and the cat's eyes effect

Sagittal coma flare is something that influences corner performance by producing odd shapes out of point-light sources. Most large aperture primes are quite prone to this effect. The Sigma 85/1.4 has some coma which is practically gone at f5.6.

         
Sigma AF 85mm f/1.4 EX
with Nikon D800
Sigma AF 85mm f/1.4 EX
with Nikon D800
Sigma AF 85mm f/1.4 EX
with Nikon D800
   
f1.4, 100 ISO
f2.8, 100 ISO
f5.6, 100 ISO

The cat's eyes test shows how circular out-of-focus highlights at the corners are rendered. It also is connected with the light fall-off in corners: the more the highlights are rendered as cat's eyes (elliptical) the less light the lens can provide in the corners.

         
Sigma AF 85mm f/1.4 EX
with Nikon D800
Sigma AF 85mm f/1.4 EX
with Nikon D800
Sigma AF 85mm f/1.4 EX
with Nikon D800
   
f1.4, 100 ISO
f2.8, 100 ISO
f5.6, 100 ISO

The Sigma 85/1.4 produces an almost circular shape from f2.8 onwards which is good and corresponds with a relatively low light fall-off in the corners. There is also only a little outlining of the red oof-dot which is a good sign for pretty bokeh.

 

 
Sigma AF 85mm f/1.4 EX with Nikon D800 in contra-light
From left to right: f1.4, f2.8 and f5.6
 

Behavior in contra-light

The image on the right shows a sequence of shots against a strong light-source shining directly into the lens but still outside the image circle of a FX-body. It shows how well the lens copes under these adverse conditions wide open and stopped down to f2.8 and f5.6.

Some lenses simply produce lower contrast when closing the aperture, although that should minimize stray-light in the lens. But unfortunately the reflections from the aperture itself sometimes cause some veiling glare.

You can judge the effect if you look at the shadows at the lower left of the camera body and the mounting-plate. The shadows become a little deeper when stopping down to f2.8 which is good. And at f5.6 the effect becomes a little more pronounced and the overall image contrast and dynamic range is increased further. The petal-shaped lens-hood seems to keep light away better than Nikon's lens-hoods.

 

Sigma AF 85mm f1.4 EX DG HSM sample images gallery

The following images were taken with the Sigma AF 85/1.4 on a D800. Each image was recorded in RAW and converted with Lightroom 4 at camera standard settings. Noise-reduction is set to 0, sharpening to 70/0.5/36/10, no extra tone, color, or saturation adjustment was used. Some images have White Balance set to a standard daylight value to make them comparable. You can click on each image to access the large original. Please respect our copyright and only use those images for personal use.

The first image shows what you can achieve in a typical landscape situation. That may not be a typical use of this lens but the Sigma AF 85/1.4 is fully capable of producing images at infinity that are full of fine details and sharp right into the corners of a very high resolution FX-sensor. Only the need to tune focus a bit farther away for maximum sharpness produced the tell-tale magenta CA at f1.4 in the center. But that is already negligible at f2.8.

Unremarkables: Infinity shot with Sigma AF 85/1.4 EX DG HSM on a D800
f5.6, 100 ISO; Below: 100% crops from main image at different apertures
 
   
f1.4, 100 ISO
 
f2.8, 100 ISO
  f4.0, 100 ISO

The next row shows 100% crops from the lower right corner. It's pretty impressive how this lens performs even wide open! And the vignetting is not that bad either.

Unremarkables: corner performance with Sigma AF 85/1.4 EX on a D800, 100% crops
 
   
f1.4, 100 ISO
 
f2.8, 100 ISO
  f4.0, 100 ISO

 

My second shot, below, should give you an impression of the bokeh that this lens can produce wide open. Very important for applications like portraiture. The 50% crops are from the background, the sharpest point, and the foreground in the overall image. They show the smooth rendering of out-of-focus elements with some slight outlining in the background. How the Sigma AF 85/1.4 performs against the mighty (and expensive) Nikon AF-S 85/1.4G will be shown in my upcoming 85mm primes shootout.

Flowers: bokeh shot with Sigma AF 85/1.4 EX @f1.4 on a D800
 
Main image and all 50% crops: f1.4, 100 ISO

 

The next shot is a portrait at f2.8. It shows excellent sharpness and contrast with some slight purple fringing on the chain (last crop).

Portrait: shot with Sigma AF 85/1.4 EX @f2.8 on a D800
 
Main image and all 100% crops: f2.8, 100 ISO

Other images shot with this lens can be found on my flickr set here in full resolution. Have a look if you like.

 

Focus and build quality

Focus accuracy and repeatability is especially critical for large aperture prime lenses with their shallow depth of field. Repeatability (=accuracy of focus on the same subject after repeated focus-acquisition) is pretty good with no real outliers over a series of 40 shots. But there is a clear focus-difference on phase-shift AF when the lens comes from infinity vs minimum focus distance (MFD). The following image presents the typical difference: on the left side focus was coming from infinity, on the right side from MFD. It is a clear indicator that the combination of this lens with my D800 over-shoots the target distance a bit.

 
 

This makes it advisable to let the lens pre-focus to get in the right ballpark regarding focus-distance and then focus a second time to nail the shot. It also makes it a bit frustrating when you try to find the correct micro-focus adjustment: one adjustment is optimal for focusing forward (i. e. to a more distant subject) and another setting is optimal for focusing closer. Best thing is to set the micro-focus adjustment somewhere in between those two values and use pre-focus as described above. The lens focuses pretty fast: around 0.5 sec from infinity to 0.85m.

The focus ring of the lens turns about 90 degrees from infinity to MFD. This throw is a little on the short side for critical manual focusing (in live-view or movies) at large apertures and the movement of the focus-ring is a bit stiff. But there is no slack/play between the focus-ring and the focus-action and AF-operation is quiet. This is supporting the general impression of solid build quality that this lens conveys: Weighty, a rubber-coated exterior giving a good grip, metal lens-mount, and nine rounded aperture blades.

 

Overall Sigma's AF 85mm f/1.4 EX DG HSM delivers some impressive performance, so let me wrap things up in my Sigma AF 85mm f/1.4 verdict.

 
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