What to look for...
Get the key ingredients for effective portraiture
DIAPHRAGM
BLADES
The Nikon AF-S 85mm
f/1.8G has seven
diaphragm blades,
whereas all the other
l e n s e s o n te s t h ave
nine, enabling a more
well-rounded
aperture when
stopping down.
STABILIZATION
O n l y th e Ta mro n l e n s i n
this test group features
an optical image
stabilizer. Unless you’re
shooting with a Z-series
body with internal
stabilization, you’ll
n e e d to b e w a r y of
camera-shake.
THE Z LIST
Budget alternatives for Z-mount lenses are
very thin on the ground, but Samyang makes
a n i n tr i g u i n g M F 8 5 mm f/ 1 .4 Z l e n s w i th f u ll
manual focusing and aperture control.AUTOFOCUS
SYSTEM
Most have ring-type
ultrasonic systems, but
the Samyang and Nikon Z
lenses have a stepping
motor with an
electronically coupled
manual focus ring,
enabling for precise
adjustments.
ELECTROMAGNETIC
AT TRACTION
Apart from the Nikon 85mm lenses
on test, all have electromagnetically
controlled apertures, making them
incompatible with some older DSLRs.APERTURE RATING
A wider aperture equates
to a tighter depth of field,
so an f/1.4 lens can give
you more creative freedom
than an f/1.8 lens, but it’s
likely to be bigger and
heavier.ome 85mm lenses go wider than
others in terms of aperture,
most budget-friendly options
have an f/1.8 rating. For head-
and-shoulders – and even half-length- portraits the DoF is tight enough to blur
subjects’ ears when you’re focused on the
eyes. Moving up to an f/1.4 lens, the DoF
becomes tighter still and you’ll often find
that only one eye is sharp in portraits.
You can also upsize to a 105mm f/1.4; the
extra 20mm in focal length and retention
of the same fast aperture rating deliver an
even tighter DoF. It’s great for when you just
want to focus all the attention on a person’s
eye and blur out everything else. Nikon and
Sigma make competing 105mm lenses,
designed to deliver ultra-smooth bokeh.
There can be problems with fast prime
lenses that could be seen as advantages
for portraiture. At their widest apertures,
sharpness towards the edges and corners
is sometimes compromised, but you may
want the outer edges of the frame to be
defocused anyway. Secondly, vignetting
can be an issue when shooting wide open,
but this results in more attention being
focused on the main subject of the portrait.
A more adverse issue is that fast primes
can serve up two flavours of colour fringing.
Lateral chromatic aberration can be an
issue with any type of lens. It shows up as
coloured lines around high-contrast edges
towards the corners of the frame. For
example, it’s sometimes visible around dark
tree branches against a bright sky. Autoin-camera corrections for this are available
in all current and recent Nikon DSLRs and
Z-series bodies when shooting in JPEG
mode, and in the View NX-i and Capture
NX-D apps when processing Raw files.
Axial or longitudinal chromatic
aberration, also known as bokeh fringing, is
a problem more associated with fast prime
lenses. It’s a failure of the lens to focus
different wavelengths of light at the same
point, and can be noticeable as coloured
borders around the borders of in-focus
objects and their defocused surroundings.
It can show up anywhere across the image,
but generally only occurs when using very
wide apertures. Some fast lenses are worse
than others for axial fringing, but it’s much
improved by stopping down a little.The cream of the crop
Here are the finesses that make some portrait lens stand above others
S
People in isolation
Shrinking the depth of field enables
you to isolate your subjectThe quality of bokeh isn’t just about the tightness of the
DoF. The design of the lens and the quality of its elements
are critical in delivering a smooth nature to background
blur, especially for bright and detailed defocused objects,
and points of light. A well-rounded diaphragm helps retain
the quality of bokeh when stopping down. The above shots
shows how it lengthens with narrowing apertures.f/2f/1.8f/2.8f/4 f/5.6f/1.4BIG TEST