Digital Camera World - UK (2019-08)

K i t Z o n e

esigned in Switzerland

and built in Korea, the

full-frame compatible Irix

15mm is available in Firefly

and Blackstone options. They’re

optically identical, but the Blackstone

has a magnesium alloy rather than

plastic casing, four weather-seals

instead of three, and fluorescent

engraved markings for easy reading.

As a manual-focus lens, the focus

ring has a smooth, precise operation.

A secondary ring enables you to lock

the focus ring at any position. Another

nice touch is that you can fine-tune the

focus ring so that the distance scale

is calibrated to your camera body.

Performance

Image quality is excellent, with minimal

aberrations. Vignetting isn’t too bad at

f/2.4, but coma and astigmatism are

pronounced, giving an irregular shape

to stars. Both factors are improved by

narrowing the aperture by an f/stop.

his manual-focus Samyang

has an astro-friendly

‘effective’ focal length

on crop-sensor cameras,

ranging from 15-16mm on APS-C

format bodies to 20mm on Micro Four

Thirds. It’s available in many mount

options, but only the Nikon fit has

built-in electronics. This enables the

aperture to be set from the camera.

Compared with most prime lenses

for crop-sensor cameras, this one is

unusual in combining a wide viewing

angle with a fairly fast f/2.8 aperture.

Manual focusing is precise and

assured. Build quality feels solid,

but there are no weather-seals.

Performance

Performance is good in terms of coma,

spherical aberration and vignetting,

helping stars to retain their natural

shape across the image frame, even

when shooting wide-open at f/2.8.

Sharpness isn’t fabulous, however.

DT

Irix

15mm f/2.4

Blackstone

£574/$675

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Lens mounts Canon EF,

Nikon FX, Pentax K

Samyang 10mm

f/2.8 ED AS NCS CS

£379/$399

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Lens mounts C a n o n E F - S ,

Canon EF-M, Fujifilm X, Micro Four

Thirds, Nikon DX, Pentax K, Sony A,

Sony E, Samsung NX

Sharpness

Sharpness is excellent across

most of the frame, even at the

widest aperture.

Sharpness

Centre sharpness is pretty

mediocre, but it doesn’t drop

off much towards the edges.

Fringing 0.79

Chromatic aberrations are

minimal, but coma and

astigmatism can be severe.

Fringing 1.61

Colour fringing can be more

noticeable than usual towards

the image corners.

Distortion -2.15

The Irix does well to minimise

barrel distortion, giving one

of the best lab results here.

Distortion -3.62

There’s a fairly typical amount

of barrel distortion for this

type of wide-angle prime.

Digital Camera verdict Digital Camera verdict

4.0 Excellent 4.0 Excellent

4.5 3.5

Features Features

3.5 4.0

Performance Performance

4.5 5.0

Value Value

4.5 4.0

Build &

handling

Build &

handling

It’s a great wide-angle

prime for general

shooting, and comes at

a very attractive price.

Coma and astigmatism

at the widest aperture

are the only spoilers

for astrophotography.

This lens works well

for Micro Four Thirds

and APS-C format

astrophotography,

where the lack of

autofocus isn’t really

a drawback. It’s great

value at the price.

120 DIGITAL CAMERA^ AUGUST 2019 http://www.digitalcameraworld.com

0

500

1,000

1,500

2,000

2,500

3,000

f/2.4 f/4 f/5.6 f/8 f/11 f/16 f/22

Centre Edge

Corner

0

500

1,000

1,500

2,000

2,500

3,000

f/2.8 f/4 f/5.6 f/8 f/11 f/16 f/22

Centre Edge

Corner

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