Amateur Photographer - UK (2019-07-27)

subscribe 0330 333 1113 I http://www.amateurphotographer.co.uk I 27 July 2019 53

At a glance

● Lens mount converter

● Fits L-mount mirrorless bodies

● Versions for Canon EF and

Sigma SA lenses

● Fully electronic communication

IN SEPTEMBER 2018 Leica, Panasonic and Sigma

formed the L-Mount Alliance, to produce cameras and

lenses based on Leica’s existing full-frame mirrorless

platform. But one problem with this nascent system is

that there are no affordable native AF lenses, with the

cheapest being the Panasonic 24-105mm f/4 at

£1,300. It goes without saying that this will put off

some potential buyers.

Help is now at hand in the shape of the Sigma MC-21,

a fully electronic mount converter that allows L-mount

camera owners to use Canon EF or Sigma SA SLR

lenses. The two versions come at radically different prices:

£249 for the EF-mount version tested here, but just

£99 for SA. Sigma has to be applauded for

recognising the loyalty of its SA mount users and

easing their transition to mirrorless.

Outwardly, the device is deceptively simple. It has

an L mount at one end for attaching to the camera

body and an EF mount at the other, separated by a

24mm metal tube to place the lens the correct

distance from the sensor. Arrays of gold-plated contacts

transmit commands between the camera and the lens,

and all the cleverness is hidden inside, with the

instructions translated from Leica to Canon-ese by

internal electronics.

Offi cially, the adapter is only fully compatible with

Sigma’s ‘Global Vision’ lenses made since late 2012

• in other words, its Art, Sports or Contemporary
  line-ups. Some may need a fi rmware update to work
  correctly, which requires Sigma’s USB Dock (£39).
  In practice, though, almost any Canon EF-mount
  lens will physically fi t and can be used to take
  photographs. However continuous AF is disabled, so
  it’s only suitable for static subjects, and electronic
  fi rst-curtain shutter mode is also unavailable.

Ve r d i c t
I tested the MC-21 on the Panasonic Lumix S1 (see page
42), using a range of lenses of various vintages right back
to 1986. With the MC-21 adapter, the camera clearly
only uses contrast detection for autofocus, so it’s
noticeably slower compared to using a native lens.
However, all my Canon and Sigma lenses worked
correctly in terms of electronic aperture control and
passing the focal length to the camera’s IS system,
including an old Sigma 400mm f/5.6 that gives aperture-
operation errors on Canon EOS DSLRs. The main catch is
autofocus; lenses with ultrasonic-type motors usually
work acceptably well, but those with micromotors are
painfully slow and inaccurate, and better used with
manual focus. But if you can live with its limitations, the
Sigma MC-21 makes the L-mount system look much
ALL PRICES ARE APPROXIMATE STREET PRICESmore appealing, especially for existing EOS users.

Sigma MC-21 Canon

EF-L converter

Andy Westlake tries out Sigma’s lens

adapter for L-mount mirrorless

● £249 for Canon EF version; £99 for Sigma SA version

● http://www.sigma-imaging-uk.com

Lens release

A large sliding release

switch on the side is used

for changing lenses.

Tripod foot

With a standard ¼in

socket, this allows better

balance on a tripod when using

larger lenses, along with

reduced strain on the

camera’s mount.

ACCESSORIES Testbench

Recommended

Shot using an old

Sigma 400mm f/5.6 APO,

with manual focus

Panasonic Lumix S1, Sigma 400mm

f/5.6 APO, 1/1000sec at f/8, ISO 800

Status light

A small LED on the side

lights up green if a lens is

compatible, or orange if a

firmware update is needed.

If the lens isn’t compatible

it won’t light up at all.

Felt lining

An anti-reflective lining

inside the adapter, along with

matte-black paint on either

face, minimises the risk of

flare from internal

reflections.