N-Photo

http://www.digitalcameraworld.com March 2016 103

Secondhand Superstar

Tamron SP AF 17-50mm f/2.8

XR Di II LD Aspherical [IF]

THIS IS A TOP-VALUE STANDARD ZOOM,

IF YOU CAN LIVE WITHOUT STABILISATION

RELEASED: 2008 (WITH AF MOTOR)

PRICE NEW: £250/$500

PRICE USED: FROM £100/$150

This is the forerunner to the

stabilised version of Tamron’s

17-50mm lens that’s featured in

this month’s Big Test (page 126).

It lacks Tamron’s ‘VC’ (Vibration

Compensation) system, but

it’s surprisingly compact and

lightweight for a constant-

aperture f/2.8 standard zoom.

Indeed, it measures a mere

74x83mm, has a 67mm filter

thread and weighs just 440g.

If you’re considering buying

the lens for a D3XXX or D5XXX

series body, you will need to go

for the A16NII edition, which was

launched in 2008. This replaced

the original version, which had no

internal autofocus motor and can

only autofocus on bodies like the

D90 and D7XXX series cameras.

Centre sharpness isn’t as good

as from Tamron’s stabilised lens

at apertures wider than f/5.6, but

corner sharpness bears up well.

There’s a touch more colour

fringing and pincushion distortion

at the long end of the zoom

range, but overall image quality is

pretty good. The big attraction is

that constant f/2.8 aperture.

KEY POINTS

Advanced optics

The optical design incorporates

an XLD (Extra Low Dispersion)

element, similar to top-grade

fluorite glass, plus an LD element

to boost contrast while reducing

chromatic aberration.

Internal focus

The front element neither rotates

nor extends during focusing,

making it easy to use filters like

circular polarisers and ND grads,

which attach via a 67mm thread.

Autofocus motor

The autofocus motor is a fairly

basic electric model, which is a

bit sluggish and noisy compared

to Nikon’s AF-S (ultrasonic

Silent-wave) actuators.

SPECS

Equivalent focal length

(on DX bodies): 25.5-75mm

Internal zoom/focus: No/Yes

Min focus distance: 0.27m

Max reproduction ratio: 0.22x

Supplied accessories: Hood

GOT A QUESTION? Email us at [email protected]

To extend the Nikon 200-500mm VR’s

telephoto reach while also retaining autofocus,

would it be better to use crop modes in the D600

or D7200, or to use teleconverters?
Mark Gniewyk, via email

JASON SAYS... The central seven points of the D600’s
autofocus system can work at f/8, enabling the 20 0-50 0mm
f/5.6 to be used with a 1 .4x teleconver ter, giving a focal leng th of
700mm. However, the widest available aperture of f/8 can make
it difficult to achieve the fast shutter speeds you usually need for
sharpness in super-telephoto shooting. In DX crop mode, the
D600 gives a 750mm effective reach at f/5.6, but the maximum
image size shrinks from 24. 3 megapixels to just 10. 3 megapixels.
You’re better off utilising the whole of the D7200’s DX-format
sensor, which gives 24-megapixel images and an effective
750mm reach. The D7200 also has a 1.3x crop mode, stretching
the reach to 975mm while still delivering 15.4-megapixel images.
The D7200’s central AF point works at f/8, so you could also add
a 1.4x teleconverter as a last resort.

Can I empty my D750’s

internal memory?
Andy Andreadelis, via email

JASON SAYS... Nikon
D-SLRs have no ‘internal
memory’ for storing images.
The internal memory
operates as a buffer, holding
data until it’s been written to
the memory card. You’re only
likely to notice a slow-down in
the maximum continuous
drive speed when capturing
long sequences of more than
15 to 3 3 images in R AW
quality mode.

How does the Sigma

105mm macro stack up

against Nikon’s equivalent?

John Young, via email

JASON SAYS... We’ve

tested both lenses

extensively. In our

experience, the performance

of the Nikon AF-S 105mm

f/2.8G IF ED VR Micro isn’ t

any better than that of the

Sigma 105mm f/2.8EX DG

OS HSM in any respect,

although it’s substantially

more expensive. Overall, the

Sigma is a much better buy.

YOUR QUESTIONS ANSWERED