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Portrait lenses explained
Professional portrait photographers may favour top-money lenses such as the Canon EF 85mm f/1.2 or Nikon 85mm f/1.4G. But for those of us who don't want to use this type of lens on a daily, money-earning basis, the respective prices of £1,700/US$2,000/AU$2,300 and £1,200/US$1,450/AU$1,800 put them beyond sensible reach.
At the other end of the scale, lenses such as the Canon EF 50mm f/1.8 cost a mere £80/US$120/AU$130, but come up short in terms of features, performance and build quality. Thankfully, there's plenty of choice to be had in the middle ground, with a range of prime (fixed length) lenses that are affordable but capable. So what makes a good portrait lens?
The first thing to consider is focal length. If you're using a camera with an APS-C format image sensor, a 50mm lens will give an effective focal length of around 75mm to 80mm. This is very close to the 85mm focal length that's considered ideal for portraiture. It enables half-length portraits to be taken from a comfortable distance of around 3m, so you can direct your subject without crowding in and making them feel awkward.
Use an 85mm lens on an APS-C camera, and you'll be able to take head-and-shoulders portraits from about the same distance. One particular advantage of using an 85mm lens for portraiture is that the short telephoto focal length has the effect of slightly compressing any prominent facial features (think noses and chins) for a bit of added flattery.
Generally, prime lenses offer superior image quality to zoom lenses, which makes the optics on test instantly appealing. Their killer feature, however, is a wide maximum aperture that's usually between f/1.4 and f/1.8. This enables a tight depth of field, so you can blur fussy backgrounds and make the person you're shooting really stand out in an image.
The lens's 'bokeh' is all-important. This is the quality of defocused areas within the image, and the aim is to produce a smooth and creamy-looking blur effect. When shooting at anything other than a wide-open aperture, one thing that helps with this is for the lens to feature a well-rounded diaphragm.
Wider apertures also help if you're taking indoor or twilight portraits and you want to make the most of ambient lighting effects without using flash. The key benefit is that you can use faster shutter speeds to enable handheld shooting, as well as freezing any slight movement in the person you're photographing, without having to greatly increase your camera's sensitivity (ISO) setting.
That said, boosting the ISO is less of an issue than it was just a few years ago, since most current cameras offer very good image quality at high sensitivity settings.
At their widest available apertures, very fast lenses often suffer from a significant drop in image sharpness. That's not always a bad thing, since it can give a soft, dreamy look to portraits. It's a good anti-wrinkle feature, for reducing the signs of premature ageing. The only real downside is that the eyes may not be as sharp as you'd like them. You may also need to use a Neutral Density filter in bright lighting conditions, to avoid exceeding your camera's fastest shutter speed.
Portrait lenses aren't just about large apertures. So-called environmental portraits are perennially popular, featuring people in their home or working environment.
When shooting, say, a craftsman in his workshop, you may want to use a small aperture to give a larger depth of field, giving clarity to the surroundings. Sharpness at small apertures can therefore also be an important consideration. As always, maximum sharpness is usually achieved at mid-range aperture settings of around f/8.
Medium apertures are useful when using studio flash lighting as well as for general portraiture. Bear in mind that if you use a very wide aperture for a head-and-shoulders portrait, the person's ears may be slightly defocused when you're focusing on their eyes.
In most portraiture, sharpness is crucial in the central region of the frame. It's a frequently used composition trick to have the person off-centre in a portrait image but, even so, sharpness at the extreme edges and corners is usually unimportant. The exception is when taking group portraits, where people on the periphery may be quite close to the corners of the frame.
It's tempting to use a wide-angle lens for group shots, for the sake of convenience, but the problem with this is that the people near the sides of the image will end up with stretched heads. It's much better practice to stand further back if possible, and to use a lens with a more standard focal length.
Fast autofocus isn't as crucial as it is for action sports or wildlife photography, but it can still be a factor. Nobody wants to miss a fleeting expression or classic moment because they're waiting for autofocus to crawl into place. Quietness of autofocus is also a bonus for shooting candid portraiture.
Canon EF 50mm f/1.4 USM - £280/US$360/AU$470
Compared with Canon's range-topping EF 50mm f/1.2L USM, this lens is much more compact, only half the weight and less than a quarter of the price. It still feels pretty robust and the front element is quite well recessed within the inner barrel.
This helps to reduce ghosting and flare, along with Canon's Super Spectra coatings, but it's still worth spending a little extra on the optional lens hood. The inner barrel extends at shorter focus distances but doesn't rotate during focusing.
Based on an eight-blade diaphragm, the aperture is well rounded, and the maximum available aperture matches the best in class at f/1.4.
Autofocus is of the Micro USM variety, involving a motor and gearwheels. This type of system is slower than ring-type ultrasonic autofocus but the Canon offers full-time manual focus override, which is normally only available in the company's ring-type USM lenses.
You can tweak the focus setting in One Shot autofocus mode without having to switch between AF/M on the lens barrel.
Autofocus is actually faster than in the Nikon 50mm f/1.4, which is fitted with a ring-type ultrasonic system. Sharpness and contrast aren't very impressive at f/1.4, and sharpness is worse than with other lenses in the group throughout the rest of the aperture range. Even so, as a portrait lens for Canon users with APS-C sensor cameras, it gives pleasing results.
Sharpness test
Full ISO 200 image, see the cropped (100%) version below.
There's a distinct lack of sharpness at f/1.4, and unfortunately it's unimpressive at any point throughout the aperture range.
Fringing test
Poorer than most competing lenses in this group at any given aperture, and colour fringing is most noticeable at around f/8.
Distortion test
It's not particularly obvious in the images, but there is some barrel distortion, which is a little high for a 50mm prime lens.
Image test verdict
Unfortunately the Canon 50mm f/1.4 doesn't really excel in any specific area of image quality and, overall, it's merely an average performer.
Canon EF 85mm f/1.8 USM - £300/US$385/AU$585
While it's understandably bigger than the Canon 50mm f/1.4 lens, this 85mm optic is still compact and has the same filter thread of 58mm. Both Canon lenses look quite similar at a glance, but the 85mm has a larger front element that isn't recessed within the barrel, making the purchase of an optional ET-65 III lens hood all the more important.
Build quality is good and the lens benefits from a ring-type autofocus system that's very fast and almost silent. It's a significant step up from the Canon 50mm's Micro USM system, both in speed and the smoothness of full-time manual focus override.
Autofocus is fully internal, so the barrel doesn't extend during shorter-range focusing. The eight-blade diaphragm gives a well-rounded aperture, similar to that of the Canon 50mm f/1.4 lens.
There's noticeably more sharpness and contrast than with the Canon 50mm lens when using the widest available aperture, albeit at f/1.8 as opposed to the 50mm's f/1.4.
Sharpness is also improved at medium apertures of around f/5.6 to f/8. The lens is almost completely free of distortion, while colour fringing and vignetting are well controlled.
With its improved autofocus system and superior image quality, this lens is better value than the Canon 50mm lens, since it's only a little dearer to buy. It's an ideal portrait optic for full-frame DSLR bodies and very useful for telephoto portraiture on APS-C cameras.
Sharpness test
Good rather than excellent throughout most of the aperture range, this lens does better than the Canon 50mm at large apertures.
Fringing test
Colour fringing is quite low and remains consistent through most of the aperture range, although it peaks at f/1.8.
Distortion test
There's very marginal barrel distortion and it's all but impossible to see in images. It's on a par with the Nikon 85mm lens.
Image test verdict
Sharper and with less colour fringing or distortion than the Canon 50mm lens, the 85mm delivers very good image quality for the money.
Nikon AF-S 50mm f/1.4G - £280/US$400/AU$550
This G-mount lens is a major update of the somewhat antiquated 50mm f/1.4D. As such, it ditches the aperture control ring, adds AF-S (Silent Wave) autofocus and has completely redesigned optics.
The good news about autofocus is that, unlike the previous lens, it works on all Nikon DSLRs, even bodies like the D3200 and D5200 that don't have a built-in AF drive.
The bad news is that, despite being a ring-type ultrasonic system, it's sluggish and slower than when using old D-mount lenses on bodies like the D7000 or any Nikon full-frame DSLR. At least the full-time manual override works well, with smoothness and precision.
The lens feels robust and well put together, complete with a weather-seal ring around the metal mounting plate. Like the equivalent Canon lens, the front element is well recessed within the inner barrel, although it does extend towards the front of the lens's outer barrel at shorter focus distances. Unlike the Canon lens, the overall physical length of the lens doesn't alter through the focus range.
Images look quite soft at wide apertures between f/1.4 and f/2.8, but sharpness improves at f/4 and is consistent across the whole frame. Barrel distortion is slightly noticeable, slightly more so than with any other lens here. Bokeh is very pleasant, thanks in part to a well-rounded nine-blade diaphragm.
Overall, it's a significant improvement over the old D-mount lens.
Sharpness test
It's poorest in the group at f/2.8, where sharpness is marginally worse even than at f/1.4. It's respectable at apertures of f/4 and smaller.
Fringing test
There's a spike in colour fringing at f/2.8, but it's fairly minimal at f/1.4 and at medium to small apertures in the range.
Distortion test
A little disappointing for a lens in this class, the Nikon 50mm does have some barrel distortion, but it's not normally noticeable.
Image test verdict
Very good overall at apertures of f/4 and narrower, the lens is let down by a lack of sharpness at wider apertures between f/1.4 and f/2.8.
Nikon AF-S 85mm f/1.8G - £380/US$400/AU$680
A relative newcomer to Nikon's range of lenses, this is a direct competitor to Canon's EF 85mm. Both lenses feature nine optical elements and ring-type ultrasonic autofocus.
The Nikon's autofocus isn't as fast as that of the Canon lens, but it's much quicker than the Nikon 50mm f/1.4G. There are only seven diaphragm blades, compared with eight in the Canon 85mm and nine in the Nikon 50mm, but the aperture is still well rounded and bokeh is nice and dreamy.
Both this lens and the Canon 85mm feature full internal focusing, so the front element remains completely fixed throughout the focus range. The diameter of the front element is about the same in both lenses, but the Nikon's is slightly further recessed and the filter thread is larger at 67mm as opposed to 58mm.
The Nikon also comes with a lens hood, rather than it being an optional extra. The mounting plate features a weather-seal ring, which is absent on both Canon lenses in the group. Handling is very refined, with smooth manual focus and full-time focus override delivered by a comfortably large focus ring.
Sharpness and contrast are impressive, even at the widest aperture of f/1.8, and both of these image attributes are excellent at apertures of between f/2.8 and f/16. Distortion is practically non-existent and there's almost no colour fringing whatsoever. Overall, it's an excellent performer that's well worth the price.
Sharpness test
There's plenty of sharpness and contrast even when shooting wide-open at f/1.8, and consistency is good through the aperture range.
Fringing test
Colour fringing is absolutely minimal at any aperture, from f/1.8 to f/16. It's the most impressive lens in the group in this respect.
Distortion test
There's just the faintest touch of pincushion distortion, but it's negligible and goes unnoticed in the vast majority of images.
Image test verdict
All-round excellence in image quality makes this a worthy new addition to the Nikon lineup and it's great value at the price too.
Olympus M Zuiko 45mm f/1.8 - £220/US$400/AU$500
Four Thirds and Micro Four Thirds cameras have a reputation for struggling to give a tight depth of field, due to their 2x focal length multiplier. However, with its moderately large f/1.8 aperture, this Olympus lens makes it feasible to blur defocused areas in images.
Compared with most of the 50mm optics in the group, this lens is a tiny thing, with a filter thread of just 37mm and weighing only 116g. From a distance, the lens barrel looks like high-grade metal, but it's actually made of plastic with a metal-like finish. Even so, build quality feels solid.
As an extra gimmick, the front 'decoration ring' can be swapped for rings of different colours. The ring also needs to be removed when fitting the official lens hood, which is an optional extra.
The MSC (Movie & Stills Compatible) autofocus system is driven from an in-camera motor. It's practically silent and, in stills mode, as fast as the quickest ring-type ultrasonic lenses here.
Full-time manual focus override is available via in-camera settings, but there's no focus distance information on the lens.
Sharpness is outstanding, even at the widest available aperture of f/1.8, but this aperture is two-thirds of a stop slower than with the 50mm f/1.4 lenses in the group. Colour fringing is a little above average and pincushion distortion is slightly noticeable.
Overall, the Olympus packs big portraiture potential into a tiny package.
Sharpness test
The maximum aperture of f/1.8 is two-thirds of a stop slower than some 50mm lenses in the group, but wide-open sharpness is superb.
Fringing test
Not quite a match for most of the lenses on test, there's some colour fringing in evidence, mostly at large aperture settings.
Distortion test
There's a little pincushion distortion with this lens, however its actual severity is less than with any of the 50mm lenses on test.
Image test verdict
Razor-sharp, especially at wide and medium apertures, the Olympus boasts very good all-round image quality with fairly minimal distortion.
Pentax SMC DA 50mm f/1.8 - £220/US$250/AU$270
Pentax's 55mm f/1.4 lens is outside the price bracket of this group, costing a hefty £600/US$800 (around AU$880). That leaves the 50mm f/1.8 but, on a direct comparison of maximum aperture, it's three times more expensive than the Canon 50mm f/1.8. So what do you get for your money?
Build quality is quite tough overall but the mounting plate is plastic rather than metal. The lens is fairly compact and lightweight, as you'd expect from a 50mm optic with a maximum aperture of f/1.8 rather than f/1.4.
There's no lens hood, but the front element is well recessed at the infinity focus setting. However, it ends up quite close to the front of the lens at the shortest focus setting, as the inner barrel extends as you focus down.
The lens doesn't have an internal autofocus motor, instead being screw-driven from a motor in the camera body. It's not particularly fast and is very noisy.
One plus point of the 'quick-shift' focus system is that you get full-time manual focus override, but it's stiff to operate unless you switch to manual focus mode on the camera body. At least the aperture is quite well rounded, based on a seven-blade diaphragm.
Sharpness is very good at f/1.8 and is excellent in the range between f/2.8 and f/11. Colour fringing is fairly low and barrel distortion is slightly less apparent than with the Canon and Nikon 50mm lenses on test.
Sharpness test
The upside of a reduced maximum aperture is that the Pentax offers extremely good sharpness at wide and medium apertures.
Fringing test
Colour fringing is impressively low at large apertures, although it rises slightly as you progress through the aperture range.
Distortion test
Like the Canon and Nikon 50mm lenses, there's a little barrel distortion, but the amount is a bit less and barely noticeable.
Image test verdict
It's rather expensive for a 50mm f/1.8 lens with only a basic feature set, but all aspects of image quality are very pleasing.
Sigma 50mm f/1.4 EX DG HSM - £360/US$450/AU$480
The Sigma 50mm f/1.4 costs more than the equivalent Canon and Nikon lenses. It's a big and heavy lens, having a 77mm filter thread and weighing in at 505g. That's getting on for twice the weight of the Canon and Nikon lenses, but it's certainly not uncomfortably heavy, and build quality feels particularly strong.
The ring-type ultrasonic autofocus system is ultra-quiet and impressively fast, with similar performance to the Canon 85mm lens in the group. Full-time manual focus override is silky-smooth. The inner lens barrel extends at shorter focus distances, putting the front element almost flush with the front of the lens at the closest focus distance.
However, the lens comes with a good quality petal-shaped lens hood plus a padded carry pouch. Matched only by the Nikon 50mm lens on test, the Sigma has nine diaphragm blades that produce a very well-rounded aperture.
The Sigma retains sharpness at f/1.4 slightly better than the Canon and Nikon 50mm lenses. However there's a blip at f/2.8 where sharpness drops to the same level as the Canon, and the Nikon runs it close at f/11.
Apart from at f/2.8, sharpness is consistent throughout the aperture range and across the whole frame, from the centre to the corners of the image. Helped by the oversized front element, vignetting is negligible. For a prime 50mm lens, pincushion distortion is a bit on the high side.
Sharpness test
There's a dip in sharpness at f/2.8, but the Sigma acquits itself very well at f/1.4-1.8 and at medium to small apertures.
Fringing test
Colour fringing is extremely low at either end of the aperture range, and the only real peak is at f/2.8, where it's still minimal.
Distortion test
As with the other 50mm lenses on test here distortion is low, but slight pincushioning can be apparent in some images.
Image test verdict
Apart from at f/2.8 where there's a dip in sharpness and a peak in colour fringing, this Sigma lens delivers very good image quality indeed.
Sony 85mm f/2.8 SAM - £200/US$300/AU$300
Suitable for portraiture on full-frame bodies such as the Sony Alpha a99, as well as for tightly framed portraits on APS-C cameras, this 85mm lens is the cheapest here.
It's light in weight but feels a bit flimsy and only has a plastic mounting plate. It's also the 'slowest' lens in the group, with a maximum aperture of a mere f/2.8. Sony does also make an 85mm f/1.4 lens but, typical of this focal length and aperture combination, it's nearly six times the price.
As a 'SAM' lens, it features a built-in Smooth Autofocus Motor. In practice, autofocus is fairly quiet but slow. You can manually override autofocus but, as with the Pentax lens, operation is uncomfortably stiff unless you switch to manual focus mode. It's a shame the small focus ring isn't textured but at least it has a distance scale printed on it.
The inner barrel extends at shorter focus distances but the front element remains well recessed at all focus distances. Sony also supplies a hood with the lens. Thanks to a seven-blade construction, the diaphragm is quite well rounded.
The maximum aperture of f/2.8 is entirely usable as sharpness is excellent from corner to corner of the frame, and contrast is impressive. However, this is a plus point we'd expect from a lens that offers a relatively small maximum aperture.
There's a little pincushion distortion, whereas colour fringing is worse than with any other lens in the group.
Sharpness test
Corner-to-corner sharpness is excellent even at the largest available aperture, although this is a relatively disappointing f/2.8.
Fringing test
Colour fringing can be quite noticeable towards the edges and corners of the frame, increasing at medium to small apertures.
Distortion test
It can't quite match the near-zero distortion of the Canon and Nikon 85mm, but there's precious little pincushion to be seen.
Image test verdict
All aspects of image quality are very impressive, with the exception of colour fringing, where the Sony comes bottom of the group.
Verdict: Best portrait lenses
As is often the case, the very fast lenses with extra-wide maximum apertures don't tend to be quite as sharp as the slower lenses.
This is amply demonstrated in our lab test results by the Canon, Nikon and Sigma 50mm f/1.4 lenses when compared with the Olympus and Pentax f/1.8 lenses in this group. The same holds true when comparing the Canon and Nikon 85mm f/1.8 lenses with the Sony f/2.8 lens.
Distortion isn't much of an issue with any of the lenses on test, but the Canon and Nikon 85mm are the most impressive, exhibiting practically no distortion at all. The Canon and Nikon 50mm lenses both have a little barrel distortion, and the Sigma 50mm has the most noticeable pincushion.
Colour fringing is also very well controlled by almost all the lenses in this group test. The Olympus scores a little worse than most, however it's the Sony that is the least impressive.
Verdict
Full of refinement, the Nikon 85mm f/1.8 boasts ring-type ultrasonic autofocus with smooth full-time manual override, and is our favourite portrait lens. It's sharp even at its largest aperture setting and sharpness is both very impressive and consistent throughout the rest of the aperture range, from corner to corner of the frame.
The provision of seven diaphragm blades is less than with the competing Canon lens, which also has slightly faster autofocus, but bokeh is beautiful.
The Sony 85mm lens has very good overall image quality, apart from noticeable colour fringing, but it has a more basic feature set, build quality feels a bit flimsy and the maximum aperture of f/2.8 is somewhat less useful.
Moving down to the 50mm mark, which is often more ideal for general portraiture with cameras that have an APS-C format image sensor, quality is mixed. Neither the Canon nor Nikon lenses give very convincing sharpness at their maximum apertures of f/1.4, and the Nikon fails to improve much even at f/2.8. Even so, both lenses give a pleasant, dreamy look to portraits taken with wide apertures.
The Sigma 50mm gives greater sharpness at f/1.8 and is impressive at medium to narrow apertures, although there's a dip in sharpness at f/2.8. Overall, it's our 50mm portrait lens of choice.
The Olympus and Pentax lenses offer great sharpness, even wide-open, but they're expensive to buy, considering they have a reduced maximum aperture of f/1.8.
