Review of the Sigma 20mm F2 DG DN


Introduction

The Sigma 20mm F2 DG DN is a fast wide-angle lens for full-frame Sony Alpha and APS-C E-mount mirrorless cameras, where it provides a 30mm equivalent focal length. It is also available for Leica / Panasonic / Sigma L-mount cameras.

This new lens is part of the Sigma I series of compact, high-performance, impeccably constructed lenses for mirrorless camera systems, which feature premium all-metal weatherproof construction, an magnetic metal lens and a metal lens hood.

The Sigma 20mm F2 for Sony was launched in February 2022, joining the 24mm F3.5 DG DN, 24mm F2 DG DN, 35mm F2.8 DG DN, 45mm F2.8 DG DN, 65mm F2. 8 DG DN and 90mm F2. 8 DG DN lenses.

It features 13 elements in 11 groups, with a special low dispersion (SLD) element to reduce chromatic aberrations and color fringing, an FLD glass element that helps correct axial chromatic aberrations, and three aspherical elements molded in high precision to help reduce the size and weight of the lens.

There’s a super multi-layer coating to minimize internal reflections so flare and ghosting don’t occur.

This lens features a dust-proof and splash-proof structure and has a minimum focusing distance of 22cm / 8.7 inches with a maximum magnification of 0.15x.

It has a rounded 9-blade diaphragm that creates attractive blurring of out-of-focus areas of the image, and an internal focusing mechanism that means the lens barrel doesn’t move.

There’s a stepping motor for fast, quiet, and precise autofocus, while the focus ring allows precise manual focus control.

A traditional aperture ring goes from f/2 to f/22 in third-stop increments with auto adjustment also available for camera-based aperture selection.

The Sigma 20mm F2 DG DN lens is available now for £649 / $699 in the UK and US respectively.

Ease of use

Sigma 20mm F2 DG DN

Weighing 370g / 13.1oz. and measuring 70mm x 74.4mm / 2.8 inches. x 2.9 inches, the all-metal Sigma 20mm F2 DG DN is quite light for such a high-end full-frame lens.

Its overall size is well suited to a camera like the Sony A1 we tested it with, as seen in the product photos.

Even with the supplied lens hood, it remains quite discreet for a 20mm lens.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

The other 20mm lens offered by Sigma is the significantly faster but much, much bigger and heavier Sigma 20mm F1.4 DG HSM, which weighs over 1kg.

Sigma’s primary target lens is the very similar Sony FE 20mm f/1.8 G, which is about the same size and weight, but is significantly more expensive.

The Sigma 20mm F2 DG DN is heavier than the comparable Tamron 20mm F/2.8 Di III OSD M1:2 lens, which weighs just 215g and is also smaller, measuring 64mm x 73mm.

The build quality is simply superb, far exceeding what you might expect from a mid-range prime lens.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

Sigma has really gone to town on the new I-Series, so much so that they’ve detailed just how much thought has gone into it.

It incorporates a brass bayonet mount which is said to be more durable than a normal metal mount.

A rubber seal is incorporated into the lens mount design to make it dust and splash resistant.

The Sigma 20mm F2 DG DN lens has a metal lens mount and accepts 62mm filters via metal threads on the front of the lens.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

The lens lacks built-in optical image stabilization, instead relying on the camera body’s stabilization system (if it has one).

The Sigma 20mm F2 DG DN lens has an adequately sized ribbed motorized focus ring that is very well damped. Manual focus is possible by using the focus mode switch to switch between AF and MF.

There are no hard stops at either end of the range, which makes focusing at infinity a bit more difficult. Polarizer users should be pleased that the 62mm filter thread does not rotate on focus.

The manual focus ring is positioned a little too close to the lens hood when installed, so much so that my right thumb rubbed the edge of the lens hood as I turned the focus ring. A minor detail, perhaps, but still of some importance on a lens where attention to detail is the defining feature.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

The Sigma 20mm F2 DG DN lens uses a stepping motor that produces quiet, near-silent and smooth focusing, making it well suited for still and video shooting, the full length of the lens remaining constant during development.

As for autofocus, it proved to be fast on the Sony A1 camera we tested it with.

We didn’t experience much “hunting” either in good or bad lighting, with the lens focusing accurately almost all the time.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

Sony’s near-flawless Eye AF works flawlessly with this lens, quickly locking on and tracking the subject’s eye despite the wide-angle view, and it fully supports Sony’s DMF and AF+MF shooting modes. Sony.

The Sigma 20mm F2 DG DN lens features a 1/3 EV aperture ring ranging from f/2 to f/22 and auto adjustment if you prefer to set the aperture via the camera body. ‘camera.

Unfortunately, there’s no Click switch on the lens barrel that lets you de-click it for silent operation during video recording.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

The Sigma 20mm F2 DG DN lens does not come with a lens case, but does come with a very good quality plastic and metal hybrid petal shaped lens hood (LH656-02) that extends the ribbed texture of the lens barrel, as well as an innovative magnetic metal lens cap (LCF62-01M), in addition to a normal plastic cap.

This dedicated metal lens cap attaches magnetically to the front surface of the lens, and there’s even an optional magnetic metal lens cap holder (CH-11) that can be attached to a bag or belt.

Note that the magnetic lens cap cannot be used with filters, and is also quite difficult to use when the lens hood is attached.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

Focal range

The 20mm focal length provides a 94.5 degree angle of view on a full frame camera.

Sigma 20mm F1.4 DG HSM

Chromatic aberrations

Chromatic aberrations, usually seen as blue or purple fringing along contrasting edges, were somewhat apparent in our test shots, showing up in very high contrast areas. The examples below illustrate the worst case scenario.

Sigma 20mm F2 DG DN

Light attenuation

With the lens set to its maximum aperture of f/2, there is very obvious light falloff in the corners, forcing you to stop by at least 3 f-stops to completely prevent it.

Sigma 20mm F2 DG DN

Distortion

There is a lot of distortion evident in JPEG and RAW files that you will need to correct in post-processing. Alternatively, most Sony Alpha cameras can automatically and successfully apply lens distortion corrections to JPEG files, but not to RAW files.

Sigma 20mm F2 DG DN

JPEG

Sigma 20mm F2 DG DN

Raw

solar stars

The Sigma 20mm F2 DG DN is capable of producing very nice sun stars when stopped at f/16 and f/22, as shown below.

The lens is, however, susceptible to flare when shooting directly into the sun, even with the supplied lens hood.

Sigma 20mm F2 DG DN

Macro

The Sigma 20mm F2 DG DN isn’t really a macro lens, offering a minimum focusing distance of 22cm / 8.7in. and a maximum magnification ratio of 1:6.7. The following examples show how close you can get to your subject.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

bokeh

Bokeh is a word used for out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth/creamy/hard, etc.

In the 20mm F2 DG DN lens, Sigma used an iris diaphragm with 9 circular blades, which resulted in attractive bokeh for what is after all a wide-angle lens.

We realize, however, that bokeh assessment is subjective, so we’ve included several examples below for your perusal, all shot wide-aperture at f/2.

Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN
Sigma 20mm F2 DG DN

Acuity

In order to show you how sharp this lens is, we provide 100% crops on the next page.

Next page
Sharpness: 1″

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