Introduction

Ease of Use

Weighing in at a mere 215g / 7.5oz. and measuring 4.6cm in length, the Sigma 45mm F2.8 DG DN is a very compact, lightweight lens that's well suited to everyday shooting.

It's significantly smaller and lighter than most of the other standard prime lenses that are currently available for Sony mirrorless cameras.

As seen in the photos below, it's a very good match for a small full-frame mirrorless camera like the Sony A7 III that we tested it with.

Build quality is excellent, which is a real bonus given the relatively affordable price tag. The lens has a metal shell, a brass mount and an aluminium lens hood.

In terms of features, the Sigma 45mm F2.8 DG DN offers most of the things that you need from a prime lens.

The main exception is the lack of built-in Vibration Reduction, although it can take full advantage of the camera's in-body image stabilisation system, if it's available (as on the Sony Alpha A7 III camera that we tested this lens with).

Focusing is usefully internal and manual focusing is possible when set via the Focus switch on the lens barrel.

Full-time manual focus override is also available at any time simply by rotating the focus ring, with the lens employing a focus-by-wire system.

There is no distance scale on this lens, though, which is a shame but not that surprising given its compact dimensions.

The Sigma 45mm F2.8 DG DN lens has a very narrow focus ring. There are no hard stops at both ends of the range, making it a little more difficult to set focus at infinity.

Polariser users should be pleased that the small, affordable 55mm filter thread doesn't rotate on focus.

When it comes to auto-focusing, the Sigma 45mm F2.8 DG DN lens is a quick performer, taking about 0.15 seconds to lock onto the subject when mounted on the Sony A7 III camera that we tested it with.

We didn't experience very much "hunting" at all, either in good or bad light, with the lens accurately focusing virtually all of the time.

It's also a very quiet performer, thanks to the built-in HSM (Hyper Sonic Motor), which makes this lens well-suited to video recording.

The Sigma 45mm F2.8 DG DN lens has a traditional aperture ring on the lens barrel, which allows you to set the aperture in 1/3 steps, complete with markings for the full apertures and every 1/3 step.

The aperture ring is nicely damped and makes a distinctive click as you change the setting. You can toggle it between auto aperture control (when the ring is set to A) or manual aperture control (the ring is set to one of the aperture values).

Unfortunately the aperture ring cannot be de-clicked, making it less well-suited for video use.

The Sigma 45mm F2.8 DG DN ships with an excellent round lens hood that's made of aluminium (LH577-01), although no case is included. It accepts 55mm filters.

Focal Range

At the 45mm focal length the angle of view is 51.3 degrees.

 

Chromatic Aberrations

Chromatic aberrations, typically seen as green or blue fringes along contrasty edges, could be detected in a few of our test shots, but they are not very prominent at all.

Vignetting

With the lens set to its maximum aperture of f/2.8, there is a little light fall-off in the corners. Stopping-down to f/5.6 virtually eliminates this.

Macro

The Sigma 45mm F2.8 DG DN isn't claimed to be a macro lens, but it delivers quite good performance nonetheless.

It has quite a usefully close minimum focusing distance of 24cm / 9.4in. and a maximum magnification ratio of 1:4.

The following example demonstrates how close you can get to your subject.

Bokeh

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

In the Sigma 45mm F2.8 DG DN lens, Sigma have employed an iris diaphragm with seven rounded blades, which has resulted in quite nice bokeh in our view when shooting wide open at F2.8.

We do realise, however, that bokeh evaluation is subjective, so we've included several examples below.

Sharpness

In order to show you how sharp this lens is, we are providing 100% crops on the following page.