N-Photo - The Nikon Magazine - USA (2019-07)

What to look for...

Keep these on your superzoom wish list

LONG REACH
The DX format lenses on
test stretch to 200mm,
300mm or 400mm. After
applying the 1.5x crop
factor, the ‘effective’
focal length becomes
300mm, 450mm or
600mm respectively.

OPTICAL

STABILIZATION

All but essential in

superzoom lenses,

competing stabilization

systems include Nikon

VR (Vibration Reduction),

Sigma OS (Optical

Stabilizer) and

Tamron VC (Vibration

Compensation). A lens

with a built-in optical

stabilizer has a dedicated

group of elements with

computer-controlled

movement to counteract

physical vibrations.

FOCUS DISTANCE

SCALE

M o s t l e n s e s i n th i s g ro u p

have a focus distance

scale, either mounted

under a viewing window

or printed on the focus

ring. However, they are

lacking in the Nikon

18-300mm and Tamron

18-200mm lenses.

ULTRASONIC MOTOR

U n li ke i n r i n g-t yp e s ys te ms , a n u l tr a s o n i c

motor assembly uses drive shafts and

gearwheels to drive autofocus. They’re

generally slower and louder in operation.

AUTOFOCUS
SYSTEM
T h e l e n s e s o n te s t w i th
ring-type ultrasonic
systems have the fastest
and quietest autofocus,
whereas motor-based
systems enable a smaller
more lightweight lens
construction.

SEALED MOUNTING PLATE

All of the Nikon and Tamron lenses on

te s t h ave a we a th e r-s e a l r i n g o n th e i r

mounting plates, to avoid the ingress of

dust and moisture. It’s lacking in both

of the Sigma superzooms.

SHORT STUFF
Most superzoom lenses
for DX format cameras
have a shortest focal
length of 18mm,
equivalent to a 27mm on
a full-frame camera.
The Tamron 16-300mm
shrinks to an effective
24mm focal length.

ny zoom lens represents a bit of

a compromise in image quality,

compared with a fixed focal

length prime. It’s only natural

that the bigger zoom range of a superzoom

lens tends to result in a greater

compromise, especially in terms of

sharpness and distortions. But, recent

designs aim to capitalize on advances

in tech, maximizing performance.

A key element in the design of

superzoom lenses is the use of ‘aspherical’

elements. Instead of having the natural

curve of a section of a sphere, these

specially moulded, or ground elements,

have irregular shapes. A single aspherical

element can replace multiple spherical

elements, greatly reducing the size and

weight of a camera lens, while also

potentially increasing quality.

Given that Nikon DSLR cameras don’t

feature sensor-shift stabilization, another

key ingredient in superzoom lenses is

optical stabilization. If you want a lens that

you can use for shooting on holiday or while

travelling, you don’t want to be lugging a

clunky tripod around with you everywhere.

Effective optical stabilization can be a major

asset in getting consistently sharp handheld

shots, especially at long telephoto focal

lengths. All of the lenses in this Big Test

feature stabilization.

We’ve come to accept autofocus as a way

of life in digital photography. However, there

are various competing systems on offer. All

of the Nikon lenses on test use ring-type

ultrasonic AF systems. They’re based on a

pair of large rings within the lens that are

driven electromagnetically at ultrasonic

frequencies. Performance tends to be quick

and whisper-quiet and there’s a handling

benefit too. The focus ring doesn’t rotate

during AF, so you don’t need to keep your

fingers clear while handholding the camera

and lens. Full-time manual override of AF is

also available, without the need to switch

from AF to MF.

The Sigma lenses on test use ultrasonic

motor-based AF systems. These enable a

smaller, more compact physical

construction but the focus ring rotates

during AF and doesn’t allow full-time

manual override. AF tends to be slower

and more audible as well.

Superzoom design

Superzooms use a lot of tech to ensure image quality remains stellar

A

Zoom extremes

Here’s how the major focal length

differences look in practice

The above series of photographs shows the approximate

difference in wide-angle potential between the varying focal

lengths of 16mm and 18mm on an APS-C format body, as

well as the longest competing zoom settings of 200mm,

300mm and 400mm. On a full-frame body, the Nikon AF-S

28-300mm f/3.5-5.6G ED VR lens gives just roughly the

same zoom range an 18-200mm lens allows for APS-C

format cameras.

28mm

18mm

200mm

300mm 400mm

16mm

BIG TEST