BEST
LENSES
It’s not all about sharpness. Here, we compare four legendary
lenses that will give you blurred vision, in a good way...
If you think about the key attributes of
high-quality lenses, sharpness is probably
one of the first things that springs to mind.
But for portrait and still-life images, bokeh can be
even more important. This is a term for the pictorial
quality of defocused areas within an image. Ideally,
photographers look for a really soft and creamy
appearance to blur fussy backgrounds and make the
main point of interest really stand out.
The first thing you’ll need in the pursuit of beautiful
bokeh is a tight depth of field. ‘Fast’ lenses with a wide
aperture rating are therefore the order of the day,
and a longer focal length is helpful. When shooting on
a full-frame camera, 85mm lenses with an aperture
rating of f/1.4 or f/1.8 are often preferred, some of
which we covered in a group test back in issue 220.
This time, we’re going further still, looking at Canon
85mm f/1.2 lenses (old and new), along with 105mm
f/1.4 lenses from Nikon and Sigma.
But there’s more to beautiful bokeh than just a
tight depth of field. Although lenses with matching
focal lengths and aperture rating technically givean identical depth of field, the quality of bokeh can
be very different in terms of smoothness – both for
defocused areas and in transitional regions between
in-focus and out-of-focus points.
Colour fringing is another factor to look out for. It’s
not just lateral chromatic aberration that’s a concern,
as fast prime lenses can be notorious for longitudinal
or ‘axial’ chromatic aberration too. This can produce a
coloured fringe around objects in front of or behind the
point of focus. Unlike lateral chromatic aberration, it
can occur at any point across the image frame, instead
of being mostly limited to the edges and corners.
Ideally, lenses should give a well-rounded
appearance to defocused lights and bright spots in an
image. A well-rounded diaphragm in a lens, typically
based on nine or more curved blades, helps to retain
this when stopping down. This is important when you
can’t shoot at the widest aperture because the depth
of field is too tight for the area you want to keep in
focus, or the lighting is so bright that your fastest
shutter speed is insufficient to avoid overexposure.
Let’s take a look at our contenders...