Sigma 28-45mm f/1.8 DG DN Art Lens Review
Sigma continue to forge ahead, this time with the first full frame zoom lens with a constant aperture of f/1.8, quite an achievement. Available in Sony FE and L mount versions, we have the FE version, so let’s couple it up to the 42MP Sony A7R III and see where it leads us. Can quality be maintained with such an ambitious specification? We find out.
Sigma 28-45mm f/1.8 DG DN Art Handling and Features
Apart from the f/1.8 maximum aperture, the spec is relatively modest at just 28-45mm, basically covering a modest wide angle to a wide standard lens. The first price we pay is the relatively large lens, weighing in at 960g (L Mount) or 950g (FE Mount) and measuring 87.8mm x 151.4mm (L) or 87.8mm x 153.4mm (FE). The lens is dust and splash resistant, but not waterproof, and the front element has a water repellant coating.
Starting our tour of the lens, there is a supplied petal lens hood that bayonets cleanly and securely into place, with a locking catch for added security. The catch is well recessed and is unlikely to be accidentally pressed. Within the bayonet fit for the hood is a standard 82mm filter thread.
First up is the electronic manual focusing ring, and as expected this is totally smooth in operation. The usual Sony focusing features are supported, including DMF (Direct Manual Focus). Just behind the focusing ring we have two AFL buttons, and these can be programmed on some bodies. The focusing is internal and does not affect the length of the lens. AF is driven by an improved High Response Linear Actuator and is certainly fast and accurate, whilst being virtually silent in operation. This near silence is particularly useful for videographers, as is the suppression of focus breathing. Focusing is down to 0.3m (11.9”) at all focal lengths and at 45mm this gives a maximum magnification of 1:4, a very useful close up facility to have.
Next up is the zoom ring, and the zooming action is also internal, so again the length of the lens does not change as we zoom. As a consequence, there is no zoom creep and the balance of the lens does not change. There are clear and accurate markings at 28mm, 35mm, 40mm and 45mm. This is quite a restricted range and in general use quite often the need could be felt to have a longer zoom, but that would presumably increase the size and perhaps cost of the lens considerably.
There is a very nicely designed aperture ring, with clearly marked one third of a stop clicks. There is a de-click switch for those who prefer it, especially useful when shooting video. There is also a lock switch. The ring can be locked into the A setting so it cannot be dislodged when using the camera to set the aperture. It can also be locked out of the A setting for situations where the aperture ring is being used, preventing A being accidentally engaged. Finally, there is the usual AF/MF switch.
Optical construction is 18 elements in 15 groups, including 5 SLD (Super Low Dispersion) and 3 Aspherical. The diaphragm comprises 11 blades, giving a rounded aperture for enhanced bokeh. There is a magnet within the lens, and the magnetic field does extend approximately 2 inches, so it is wise to avoid placing credit cards with magnetic strips and similarly vulnerable items close to the lens.
Finally, we have Sigma’s usual beautifully engineered brass mount, available in Sony E fit and L mount. The L mount version is compatible with the USB Dock UD-11.
For Image Stabilisation we look to the camera body as there is none built into the lens itself, and this works well, enhancing the possibilities for low light photography. The f/1.8 aperture is also a huge advantage in low light, although the depth of field at very wide apertures will be quite slim.
Sigma 28-45mm f/1.8 DG DN Art Performance
At 28mm, central sharpness is excellent at f/1.8 and f/2, outstanding from f/2.8 to f/8 and excellent at f/11 and f/16. The edges are very good through the entire range from f/1.8 to f/16.
At 35mm, central sharpness is excellent from f/1.8 right through to f/16. The edges are very good at f/1.8 and f/2, excellent from f/2.8 to f/11 and very good at f/16.
At 45mm, central sharpness is excellent right through from f/1.8 to f/16, and the edges are also excellent from f/1.8 to f/16.
This is a great performance, and the lens is fully usable at all apertures and focal lengths for beautifully sharp and crisp images.
Sigma 28-45mm f/1.8 DG DN Art MTF Charts
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How to read our MTF charts
The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges.
For this review, the lens was tested on a Sony A7R III using Imatest. Want to know more about how we review lenses?
CA (Chromatic Aberration) is very well controlled throughout, both centre and edge, but especially at the centre. It is unlikely that further correction will be needed.
Distortion is minimal throughout and gives us an approaching rectlinear zoom. Barrel distortion at 28mm measures just -0.28%. As we zoom in this changes to a small amount of pincushion, measuring +0.03% at 35mm and +0.23% at 45mm. This is really excellent and architectural shots will keep straight lines nicely straight.
Bokeh is smooth and satisfying, the gradation being beautifully subtle.
Sigma 28-45mm f/1.8 DG DN Art Chromatic Aberration Charts
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How to read our CA charts
Chromatic aberration (CA) is the lens’ inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.
Apochromatic lenses have special lens elements (aspheric, extra-low dispersion etc) to minimize the problem, hence they usually cost more.
For this review, the lens was tested on a Sony A7R III using Imatest.
Flare is very well controlled, even with very severe backlighting. It is very difficult to generate any artefcats, but some slight signs of flare can be seen under the harshest lighting. This is not likely to be a problem.
Vignetting is modest for a zoom lens, but if the slight corner darkening should be noticed, then there are always software solutions.
| Aperture | 28mm | 35mm | 45mm |
| f/1.8 | -1.4 | -1.1 | -1.7 |
| f/2 | -1.3 | -1.1 | -1.7 |
| f/2.8 | -1.2 | -1 | -1.4 |
| f/4 | -1.2 | -1 | -1.4 |
| f/5.6 | -1.1 | -1 | -1.3 |
| f/8 | -1.1 | -1 | -1.3 |
| f/11 | -1.1 | -0.9 | -1.3 |
| f/16 | -1.1 | -0.9 | -1.3 |
Sigma 28-45mm f/1.8 DG DN Art Sample Photos
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Sigma 28-45mm f/1.8 DG DN Art Aperture range
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Value For Money
The [AMUK]Sigma AF 28-45mm f/1.8 DG DN Art|Sigma+AF+28-45mm+f/1.8+DG+DN+Art[/AMUK] lens is priced at £1299.00
Alternatives might be:
- [AMUK]Samyang AF 24-70mm f/2.8|Samyang+AF+24-70mm+f/2.8[/AMUK], £828
- [AMUK]Sigma 24-70mm f/2.8 DG DN Mk II|Sigma+24-70mm+f/2.8+DG+DN+MK+II[/AMUK], £1179
- [AMUK]Sony FE 24-70mm f/2.8 GM II|Sony+FE+24-70mm+f/2.8+GM+II[/AMUK], £1999
None of these approach the f/1.8 aperture, but they do have wider zoom ranges. Clearly the choice is there, but if the speed (brightness) of the new lens is needed, then the choice is pretty clear.
Sigma 28-45mm f/1.8 DG DN Art Verdict
Very fast lenses do have their place, often justified by the low light possibilities, but also for the ability to throw backgrounds out of focus for gorgeously smooth bokeh. Of course nothing is free, so the price is in the cost, the size and the necessity to focus extremely accurately at the widest apertures. For those who shoot mainly in fairly bright daylight, then the need may be reduced, but for those who venture out after dark there will be huge potential in the new lens and many new creative possibilities. The lens is quite big and heavy, although to be fair, Sigma’s claim that it is quite compact and is held at under 1kg weight also has validity – they have achieved something special in keeping it as trim as they have.
All in all a very exciting lens that is a dream to use, and one that can be happily awarded the accolade of Editor’s Choice.
Sigma 28-45mm f/1.8 DG DN Art Pros
- Excellent to outstanding sharpness
- Super-fast f/1.8 constant aperture
- Well controlled CA
- Very low distortion
- Dust and moisture resistance
- Moderate vignetting
- Close focusing to 1:4
- Excellent AF performance
- De-clickable aperture ring
- Ultra-smooth bokeh
- Virtually no flare
- Fair price
Sigma 28-45mm f/1.8 DG DN Art Cons
- Quite large and heavy
- Modest zoom range
[REVIEW_FOOTER]R_features=4.5|R_handling=5|R_performance=5|R_value=4.5|R_overall=5|A_level=5|A_text=Editor’s Choice – Superb results from this super-fast zoom lens that opens up new low light and creative possibilities|E_id=8027[/REVIEW_FOOTER]
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Source: Photography News
Sigma 28-45mm f/1.8 DG DN Art Lens Review
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