Fast lenses group test

A major bonus of fast lenses is that they allow you to use faster shutter speeds in low light, fending off the problems of both camera shake and motion blur, the latter of which can’t be fixed with any amount of optical image stabilisation. Large apertures also create a shallow depth of field, which is especially good for blurring the background in portraits.

With this in mind, a ‘standard’ 50mm focal length equates to about 75mm to 80mm with most D-SLRs, which use APS-C rather than full-frame sensors. Therefore they offer a perfect effective focal length for taking portraits. As well as offering a two-stop increase in speed at focal lengths of around 50mm, compared with most standard ‘kit’ zoom lenses, the fast zooms on test also boast constant aperture, so the maximum aperture is available throughout the zoom range.

The downside is that while zooms are unbeatable for versatility, there’s an inevitable compromise in optical quality. Go for a fast prime lens and you can generally expect a further two-stop increase in speed, with a maximum aperture of around f/1.4, negligible distortion at the fixed focal length and supreme sharpness.

Canon EF 50mm f/1.4 USM
Street price: £290

This model firmly occupies the prime lens middle ground between Canon’s rather basic 50mm f/1.8 and the massively expensive 50mm f/1.2L USM, costing nearly £1,300. It delivers a more standard f/1.4 maximum aperture and fast, near-silent USM (Ultrasonic Motor) Autofocus, complete with full-time manual override.

Rugged but fairly light in weight, it’s easy to live with. As with most Canon lenses, however, you have to pay extra for a lens hood, which will set you back £25. Optical performance proved respectable in our tests; the lens produced reasonably crisp images even under very low indoor lighting, but the drop-off in sharpness was more obvious at the maximum aperture than with some other lenses here, especially towards the corners of the frame.

Outdoors, the Canon’s resistance to flare was average but, even so, image quality is a big step up from Canon’s cheaper kit zoom lenses.

At its largest aperture, the Canon EF 50mm isn’t the sharpest tool in the box, but a major plus point of this is that the lens can give an attractive ‘dreamy’ look to your portraits. Stopped down a bit for this studio-lit shot, there’s plenty of detail throughout most of the image, but it could be a little better in the corners of the frame. Even so, there’s certainly a lot to like about this lens.

Verdict: Features **** / Build quality **** / Handling ***** / Image Quality **** / Value for Money **** Overall *****

Nikon AF-S 50mm f/1.4G
Street price: £280

Nikon’s reasonably priced 50mm f/1.8 lens only costs about £100, but is so sharp you can practically cut yourself on it. At nearly three times the price, this f/1.4 lens has its work cut out to justify the outlay, but it’s still the cheapest lens here.

As well as the slightly larger maximum aperture, the newer f/1.4G is much more of a 21st-century lens, dropping the antiquated aperture ring that is largely superfluous on D-SLRs, and adding Nikon’s Silent Wave AF-S autofocus system. As with Canon’s USM, this means you get whisper-quiet autofocus with full-time manual override, although autofocus speed isn’t as rapid as with some of Nikon’s other AF-S lenses.

At apertures of f/2.8 and smaller, sharpness proved great across the frame and, even wide open at f/1.4, it’s way above average. The quality of bokeh was also particularly pleasing, and overall the f/1.4G is worth every penny.

Every tiny nuance is captured by the razor-sharp Nikon and, when viewed at 100% magnification on a computer screen, this test shot reveals a level of detail that simply can’t be seen with the naked eye. For portraiture, it’s perhaps a little too sharp and accentuates every wrinkle and flaw in the skin. This can be easily fixed in Photoshop though, and we’d rather have too much detail to start with than not enough.

Verdict: Features ***** / Build Quality ***** / Handling ***** / Image quality ***** / Value for money ***** / Overall *****

Click through the next pages to see how the other lenses in our test fared.