Introduction

Ease of Use

Weighing in at 435g and measuring 6.3cm in length, the Sigma 30mm F1.4 DC A is a relatively compact lens given its fast f/1.4 aperture. As seen in the photos below, it complements a camera like the Canon EOS 70D / Rebel T5i very well.

The Sigma 30mm F1.4 DC A lens mounted on a Canon EOS 70D

The Sigma 30mm F1.4 DC A lens mounted on a Canon EOS 70D

The Sigma 30mm F1.4 DC A lens mounted on a Canon EOS 70D

Build quality is excellent given the relatively affordable price tag. The lens has a plastic shell with a mixture of metallic parts and a new compound material, TSC (Thermally Stable Composite), used inside. It also incorporates a brass bayonet mount that's supposed to be more durable. The optical elements are made of high-grade glass. The focus ring is wide enough given the size of the lens and ridged for easier grip.

The Sigma 30mm F1.4 DC A lens alongside the Canon EOS 70D

Side of the Sigma 30mm F1.4 DC A lens

Front of the Sigma 30mm F1.4 DC A lens

Rear of the Sigma 30mm F1.4 DC A lens

In terms of features, the Sigma 30mm F1.4 DC A offers all the basics that you need from a standard prime lens. The main exception is the lack of built-in Vibration Reduction, although the very fast maximum aperture of f/1.4 makes up for this.

Front of the Sigma 30mm F1.4 DC A lens

Rear of the Sigma 30mm F1.4 DC A lens

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.

A clear distance scale in both feet and meters runs from the closest focusing distance of 0.3m / 0.98 ft to infinity.

Surprisingly given its price, the Sigma 30mm F1.4 DC A ships with a good quality soft case and also a plastic circular-shaped lens hood. It accepts 62mm filters.

The Sigma 30mm F1.4 DC A lens in-hand

The Sigma 30mm F1.4 DC A lens fitted with the supplied LH686-01 lens-hood

Focal Range

At the 30mm focal length the angle of view is 50.7 degrees.

 Field of view at 30mm

Focusing

The Sigma 30mm F1.4 DC A lens has a fairly wide focus ring. There are hard stops at both ends of the range, making it easier to set focus at infinity. Polariser users should be pleased that the 62mm filter thread doesn't rotate on focus.

When it comes to auto-focusing, the Sigma 30mm F1.4 DC A zoom is a pretty quick and reliable performer, taking about 0.20 seconds to lock onto the subject when mounted on the Canon EOS 70D that we tested it with.

We didn't experience much "hunting", either in good or bad light, with the lens accurately focusing almost 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.

Chromatic Aberrations

Chromatic aberrations, typically seen as purple or blue fringes along contrasty edges, can be detected in quite a lot of our sample shots - this is definitely one of the Sigma 30mm F1.4 DC A's weak points in terms of image quality.

Vignetting

With the lens set to its maximum aperture of f/1.4, there is significant light fall-off in the corners at both ends of the zoom range. Stopping-down to f/4 virtually eliminates this. There is also some quite obvious barrel distortion.

Macro

The Sigma 30mm F1.4 DC A isn't claimed to be a macro lens, but it delivers reasonable performance nonetheless. It has a minimum focusing distance of 30cm/11.8in and a maximum magnification ratio of 1:6.8. The following example demonstrates how close you can get to your subject, in this case a Compact Flash memory card.

Close-up performance

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 30mm F1.4 DC A lens, Sigma employed an iris diaphragm with nine rounded blades, which has resulted in very nice bokeh in our view. We do realise, however, that bokeh evaluation is subjective, so we've included several 100% crops for your perusal.

Sharpness

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