Sigma 45mm f/2.8 DG DN Contemporary lens
The Sigma 45mm f/2.8 DG DN Contemporary lens is a very nice bit of gear; robustly built and compact and light enough to be easy to carry.
The metal barrel and lens hood have a ‘quality’ look and feel and the presence of an aperture ring and nicely tuned focusing ring are icing on the cake.
Its near-silent focusing makes it a good choice for video work, particularly on a camera with phase-detection AF.
The lack of stabilisation and partial weather sealing are the only areas that could merit criticism, although this would be negated by using the lens on a camera with sensor-shift IS.
The Sigma 45mm f/2.8 DG DN Contemporary lens was first released in July 2019 with an E-mount for Sony’s ‘full-frame’ mirrorless cameras and, more recently with an L-mount to coincide with the launch of the Sigma fp camera. Relatively compact and light for a full-frame lens, it has an all-metal body and comes with a matching metal lens hood (LH577-01). We received this lens with the L-Mount and tested it on the Sigma fp camera, which is reviewed separately.
Side view of the 45mm f/2.8 DG DN Contemporary lens with the supplied lens hood. (Source: Sigma.)
The optical design of this lens is straightforward, with eight elements in seven groups, among them two aspherical elements. Sigma’s Super Multi-Layer Coating has been applied to reduce flare and ghosting and the lens is compatible with in-camera corrections for peripheral illumination, chromatic aberrations and distortion.
The optical design showing the positions of the two aspherical elements. (Source: Sigma.)
Focusing is driven by a stepping motor which is fast and near-silent, although it means there’s little in the way of tactile feedback when focusing manually. The lens is supplied with the usual front and end caps plus a metal cylindrical lens hood with a bayonet mounting and ribbed outer surface.
Who’s it For?
The 45mm focal length covers an angle of view of 51.3 degrees, which fits into the ‘standard’ category but is a little wider than the traditional 50mm standard lens. On a full frame camera, this focal length is well suited to street photography but a little limited for general-purpose shooting and travel photography when compared with the kit zooms bundled with many cameras.
The minimum focus distance of 24 cm is also a bit restricted when it comes to close-ups. It’s fine for medium-to-large flowers and similarly-sized subjects but the lack of stabilisation means care is required when shooting in dim lighting with low ISO settings, where slow shutter speeds will be required.
Note: The E-Mount version of this lens can also be used on Sony’s APS-C cameras, where it would cover a focal length equivalent to 67.5mm on a 35mm camera, which is close to ideal for portraiture.
Build and Ergonomics
Aside from the lack of stabilisation, in general the build quality of this lens is outstanding, as you’d expect from its ‘Made in Japan’ label. Its all-metal construction – including the supplied lens hood – puts it ahead of other similarly-priced prime lenses for full-frame cameras and it feels very nice to use.
The provision of an aperture ring, something that has become less common in modern lenses, is another bonus. And while there’s a nice band of ribbing on the ring to provide a secure grip, there’s no distance scale since focusing is controlled by the camera.
Angled view of the 45mm f/2.8 DG DN Contemporary lens without the supplied lens hood. (Source: Sigma.)
Physically this lens is relatively small and a good match for the Sigma fp camera we used for our tests. The focusing ring is 7 mm wide and positioned just behind the bayonet fitting for the lens hood. Most of its surface is clad in fine ridging.
Roughly 4 mm behind it is the aperture ring, which is approximately 10 mm wide and carries a 5 mm wide band of ridging around most of its trailing edge. Aperture settings from f/2.8 to f/22 plus an ‘A’ (Auto) setting are situated in an un-ridged section of this band. Click-stops are provided at 1/3EV intervals to allow easy adjustments.
The lens barrel runs straight for about 13 mm before stepping outwards in a 4-5 mm wide band that surrounds the brass mounting plate. An AF/MF slider switch is located in this section of the barrel where it’s easily reached by the thumb when the lens and camera are cradled in the left hand.
The metal lens mount is solid enough to match the rest of the lens and it’s surrounded by a thin rubber seal. Although this is the only weatherproofing provided, it should provide some dust- and splash-resistance, although not as much as full weather-sealing.
The review lens performed well in our Imatest tests, delivering centre-of-frame resolution that was above expectations for both JPEGs straight out of the camera and DNG.RAW files, which were converted into 16-bit TIFF format with Adobe Camera Raw. Edge resolution was slightly below the expected level, as shown in the graph of the results of the JPEG tests below. (This was also true for the raw files.)
The highest centre resolutions occurred between f/2.8 and f/5.0, after which there was a steady decline to f/22, the minimum aperture for this lens. As expected differences between centre and edge resolution reduced as the aperture was stopped down. Diffraction began to take effect from about f/6.3 on but was evident by about f/9.
Lateral chromatic aberration remained entirely within the ‘negligible’ band for both JPEGs and DNG.RAW files, with JPEGs showing the effects of in-camera corrections for this issue. In the diagram of the JPEG results, below, the red line marks the border between ‘negligible’ and ‘low’ CA.
Rectilinear distortion was low, with very slight pincushion distortion just detectable when no in-camera corrections were applied. Vignetting was apparent as corner darkening at f/2.8 in uncorrected files. Stopping down reduced the darkening gradually but it didn’t completely disappear until around f/5.6.
Bokeh quality depends a lot on the brightness of the background. With relatively dark, low-contrast backgrounds, tonal transitions were generally soft and smooth. Foreground blurring tended to be a little ‘harder’.
Bright highlights in backgrounds tended to be rendered as circular blobs, which became more diffuse with distance from the focused subject. Outlining was common in smaller highlights but undesirable ‘onion rings’ were barely visible.
Because autofocusing is driven from the camera, on cameras with hybrid or phase-detection AF systems, it would probably be consistently fast and accurate. But the Sigma fp’s contrast-based system wasn’t totally consistent and focusing in Cine mode was often slow to find and track subjects. Performance was better with stills, where the main problems were with low-contrast subjects.
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Picture angle: 51.3 degrees
Minimum aperture: f/22
Lens construction: 8 elements in 7 groups (including 2 aspherical, elements)
Lens mounts: L-Mount
Diaphragm Blades: 7 (circular aperture)
Focus drive: Stepping motor
Minimum focus: 24 cm
Maximum magnification: 0.25%
Filter size: 55 mm
Dimensions (Diameter x L): 64 x 46.2 mm
Weight: 215 grams
RRP: AU$825; US$559
Distributor: C.R. Kennedy & Company, (03) 9823 1555, www.crkennedy.com.au/photo
Based on JPEG files taken with the Sigma fp camera.
Vignetting at f/2.8.
This pair of images shows the differences in depth of field between shots taken at open aperture (top) and with the lens stopped down (below). ISO 400.
ISO 100, 1/125 second at f/8.
Crop from the centre of the above frame magnified to 100%.
Crop from the edge of the above frame magnified to 100%.
Backlit scene photographed at ISO 100, 1/250 second at f/8.
Crop from the above image magnified to 100% to show no coloured fringing.
Two versions of a shot taken under strong backlighting. The top shot is from a JPEG file and the lower one from a DNG.RAW file captured simultaneously. ISO 400, 1/1000 second at f/8.
Close-up; ISO 400, 1/3200 second at f/2.8. JPEG file.
Crop from the above image at 100% magnification.
Close-up of a subject with a relatively evenly-lit dark background showing smooth bokeh. ISO 200, 1/500 second at f/2.8.
Close-up of a subject with bright points in the background showing circular highlights, even with the lens stopped down. ISO 100, 1/320 second at f/5.
Close-up of a subject with a relatively evenly-lit bright background showing mixed bokeh. ISO 100, 1/400 second at f/2.8.
ISO 100, 1/2500 second at f/2.8.
ISO 100, 1/320 second at f/9.
ISO 100, 1/50 second at f/11.
ISO 100, 1/30 second at f/10.
ISO 400, 1/400 second at f/5.6.
ISO 100, 1/250 second at f/8.
Additional image samples can be found with our review of the Sigma fp camera.
- Build: 9.2
- Handling: 9.0
- Image quality: 8.9
- Versatility: 8.8