Marc Alhadeff tested the Sigma 28mm F/1.4 FE lens:

The Sigma 28m F1.4 DG HSM Art (1250 euros) is a excellent lens 

Pros

• Excellent sharpness ,
• Fast, silent reliable AF
• Superb background blur and very beautiful 3D effect at F1.4
• Very good bokeh balls
• Low distorsion ,
• Low CA,
• Lightroom Lens profile available to correct vignetting and distorsion
• No Flare 

Average

• Price (1250 euros)

Cons

• Size 123mm
• Weight (985g)

Optically it is much better than the Sony 28mm F2 , and if you like the 28mm focal length and are ready to support its weight and size it is a highly recommended lens

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Sigma 28mm f/1.4 at Bhphoto, Amazon, Adorama.

Sigma 45mm f/2.8 FE at Adorama, BHphoto, Amazon, FocusCamera, Henrys.
In EU at Calumet DE, ParkUK, WexUK.

I know the new Sigma 45mm f/2.8 FE lens lacks some of those exciting technical specs people like. It has a moderate f/2.8 aperture and it has not the “ART” badge Sigma uses for their superfast and best lenses. But if you think it through this lens is quite unique in the FE lens lineups: It’s compact and it has an aperture ring. Probably an ideal lens for street shooters like me. Let’s check out the latest reviews of this lens:

Bjorn Petersen (Click here) tested the new Sigma 45mm f/2.8 DG DN Contemporary Lens

It’s the type of lens that excites me most since it is so practical and pragmatic, but not lacking on any valuable front. You’ll notice I’m often comparing or relating this lens’s attributes to Sigma’s Art series throughout this article, but I didn’t necessarily note that this is a Contemporary series lens. The reason I did this is because I truly felt like the quality of this lens more resembled that of an Art lens than my former impressions of their Contemporary series. The only distinguishing feature that keeps this 45mm f/2.8 from being considered an Art prime, in my mind, must be the f/2.8 design… which, in the end, is something I consider one of its strengths.

Fred Miranda (Click here) writes about this lens:

The 45/2.8 Contemporary gets many things right but what makes it unique is the butter smooth rendering.
It’s well-built, compact and light. The aperture ring stops down in one-third increments with great precision. The manual focus ring has linear coupling and is a joy to use. Optimized for mid and long distances, it is capable of high resolution across the entire image field. The f/2.8 maximum aperture restricts the amount of blur and subject isolation, however, starting at the transition zone, rendering is smooth and pleasant. It’s refreshing to see Sigma focus on rendering with their latest mirrorless designs for the E-mount.

Another strength is color aberration correction. I struggled to find color fringing in any of my test images even under high contrast lighting. Slight traces of longitudinal CA are still present – but overall, the lens is well corrected for CA.

The aperture mechanism is equipped with seven ’rounded’ blades which prevents the lens from rendering defined sunstars at mid-range apertures. However, when stopped down to f/18-22, it still produces defined 14-point sunstars.
Rounded blades are very popular with AF lenses because it maintains circular specular highlights at smaller apertures. In the case of the Sigma 45/2.8, bokeh is still circular at f/4.5. (This would not be possible if it was equipped with straight blades)

On the negative side, flare resistance is average with good retention of contrast while ghosting is visible under backlit situations. AF is a mix bag. It’s fast and quiet but there are issues with phase detection (AF-C). It consistently back-focuses and hopefully this is an easy firmware fix for Sigma. AF works great in AF-S mode (contrast-detection). The lens is not equipped with a floating element system so expect image degradation at close distance.

For those looking for a light and compact walk-around AF lens with superb rendering and color correction, the new Sigma 45/2.8 Contemporary may be what you’re waiting for.

New Sigma FE lenses:
Sigma 35mm f/1.2 FE at Adorama, BHphoto, Amazon, FocusCamera, Henrys. In EU at Calumet DE, ParkUK, WexUK.
Sigma 14-24mm f/2.8 FE at Adorama, BHphoto, Amazon, FocusCamera, Henrys. In EU at Calumet DE, ParkUK, WexUK.
Sigma 45mm f/2.8 FE at Adorama, BHphoto, Amazon, FocusCamera, Henrys. In EU at Calumet DE, ParkUK, WexUK.