N-Photo

STANDARD DX ZOOMS

Step by step: Get sharper handheld shots

1 Auto ISO
Give optical stabilisation a helping hand by
switching to Auto ISO. Your camera will then
sense when shutter speeds are getting slow
for any given zoom setting and increase the
sensor sensitivity automatically, but only by
as much as is required to keep things sharp.

2 Aperture-priority

For good front to back sharpness, you’ll

need to extend the depth of field. Switch to

aperture-priority shooting mode and dial in

a fairly small aper ture of around f/1 1 to f/16.

Again, Auto ISO will increase the sensitivity

as required.

3 Shutter-priority

When you need to freeze moving subjects,

you’ll need a fast shut ter speed. Switch to

shutter-priority mode and set a speed of

around 1/250 sec or faster. Beware of

exceeding the limits of Auto ISO under dull

lighting, which will result in dark images.

BOOST THE EFFECT OF STABILISATION WITH THESE IN-CAMERA SETTINGS

10 things we learnt during this test

1

MIND YOUR FINGERS

In all the lenses except those

with ring-type ultrasonic systems

(see table, page 134), the focus ring

rotates during autofocus.

2 FASTER MEANS BIGGER

Standard zooms with a

relatively wide constant f/2.8

maximum aperture tend to be

bigger and heavier.

3

GOING LONG

There can be a big difference

in the amount of telephoto reach

on offer – from 50mm to 105mm

(75mm to 157.5mm effective).

4

GOING WIDE

The Nikon 16-80mm and

16-85mm rule the roost when it

comes to delivering a really wide

maximum viewing angle.

5

EXTENDING BARRELS

Unlike many constant-

aperture zoom lenses, all of the

lenses in this test physically

extend at the longer end (or

sometimes both ends) of

the zoom range.

6

INTERNAL FOCUSING

All of the lenses in this group

apart from the Nikon 18-55mm have

fully internal focusing mechanisms,

so the front element neither extends

nor rotates.

7

FILTER FRIENDLY

Even though the Nikon

18-55mm extends at shorter focus

distances, the front element doesn’t

rotate, so circular polarisers and ND

grads can still be used.

8

FILTER THREADS

The diameter of filter threads

for lenses in this group ranges from

a small 52mm to a fairly large 77mm.

9

DISTORTION CORRECTION

All current Nikon D-SLRs

have a menu option for automatic

distortion correction, but only for

Nikon lenses.

10

ROUNDED APERTURES

Typically, standard DX lenses

feature seven diaphragm blades to

give a well-rounded aperture. The

Nikon 17-55mm goes two better,

with a nine-blade diaphragm.

THERE ARE PROS AND CONS TO COMPETING STANDARD ZOOMS

How we do our tests

WE COMBINE RIGOROUS LAB TESTS

WITH REAL-WORLD SHOOTING FOR THE

MOST ACCURATE RESULTS POSSIBLE

To test real-world performance, we use lenses in

wide-ranging lighting conditions on a variety of

different camera bodies. We check for good build

quality and handling, smooth and precise operation

of zoom and focus rings, and test the speed and

accuracy of autofocus, and the effectiveness of

optical stabilisation (where featured).

We also run a full range of lab tests under

controlled conditions, using the Imatest Master

software. Photos of test charts are taken across the

range of apertures and focal lengths and analysed

for sharpness, distortion and chromatic aberration

(colour fringing). A summary of these results is

shown with each review, but we also take data from

a wider range of settings into consideration. Finally,

we combine the lab tests and real-world shooting

results to give overall ratings.

http://www.digitalcameraworld.com March 2016 129