Our eyes have a focal length of around 50mm, in terms of the 35mm film equivalent. It is the reason so many photographers prefer to shoot with a standard prime 50mm lens.
The Sigma 30mm f1.4 DC DN Contemporary prime lens provides such a focal length. It gives a focal length of 60mm for Micro Four Thirds (MFT) cameras, and 45mm for Sony E-mount cameras.
For this review, I tested the MFT version, using a Panasonic Lumix DMC-GX85 mirrorless camera.
Made mostly of metal, the lens is quite well built but yet lightweight. There are no physical buttons on the lens. Everything is controlled electronically via the mirrorless camera.
The lens construction consists of nine high-grade glass elements in seven groups. Sigma claims that the lens construction design helps to minimise flare and ghosting.
The lens unit also comes with a long lens hood that helps to reduce glare. It incorporates a stepping motor for quick and quiet autofocusing (AF), making it great for video recording.
PRICE: $488 (Micro Four Thirds mount, version tested; Sony E-mount)
FOCAL LENGTH: 30mm
MAXIMUM APERTURE: f/1.4
MINIMUM APERTURE: f/16
MINIMUM FOCUSING DISTANCE: 30cm
VALUE FOR MONEY: 4/5
I found the AF to be quick and accurate. It secured a focus in less than 1sec in both bright light and low lighting conditions.
It lacks a built-in image stabiliser, but its big f/1.4 aperture should more than make up for it.
Having such a large aperture not only minimises camera shake, but it also produces a beautiful bokeh effect - the deliberately blurred out-of-focus areas in an image. With this lens, I was able to get a bokeh effect that has the wow factor.
Images produced through this lens were sharp and crisp - especially in the centre - even at f/1.4 where images tend to be soft. I found that the best edge-to-edge sharpness was achieved when the aperture was stepped down to f/8.
Vignetting is a slight problem at f/1.4, but it is an issue almost all prime lenses have at this large aperture. Adjusting the aperture size to f/4 eliminates most of the vignetting. However, I spotted slight chromatic aberrations, or purple fringing, in images across all aperture settings. But it is not really noticeable unless you blow up the picture to "pixel peep".
Considering that a Canon 50mm f/1.4 lens costs $618, this Sigma prime lens is really great value for money.
Also, if you have an MFT camera, there is not much of an option when it comes to an f/1.4 fast lens.
•Verdict: If you are looking for an affordable fast prime lens for your MFT or Sony E-mount cameras, you should seriously consider the Sigma 30mm f/1.4 DC DN Contemporary.