This lens produces a strong change in subject size through a full-extent focus distance adjustment.

Wide open there is noticeable light falloff of roughly 2.2 EV, stopped down to f/2.0 this improves to 1.7 EV, stopped down to f/2.8 it is 1.1 EV and further improves to 0.8 EV at f/8.0. You can either correct this in Lightroom or directly in camera. How does this lens handle shooting towards bright light sources such as the sun, or the street lights of a busy cityscape? I have always found Sigma to have excellent lens coatings that prevent sun flare and a general loss of contrast, shooting toward bright lights.As first seen in the recently introduced Sigma 60-600mm F4.5-6.3 DG DN OS Sports Lens, Sigma's HLA (High-response Linear Actuator) is featured in the 50mm F1.4 DG DN Art Lens. Axial CA remains somewhat persistent when stopping down, with the color misalignment effect increasing with defocusing. One-stop of shading is often used as the visibility number, though subject details provide a widely varying amount of vignetting discernibility.

The Sigma 40mm 1.4 Art does feature a floating elements design and the performance at the minimum focus distance can be described as decent at f/1.4, good at f/2.0, and excellent at f/2.8. Across frame performance is really good, there is only minimal field curvature visible. Flare resistance Sony A7rII | Sigma 40mm 1.4 Art | f/11 Spherical aberration, along with spherochromatism, or a change in the amount of spherical aberration with respect to color (looks quite similar to axial chromatic aberration but is hazier) are other common lens aberrations to observe. On a full-frame body, a 50mm focal length provides an angle of view that seems natural, and that aspect brings great general-purpose usefulness. Autofocus is handled by Sigma’s Hyper Sonic Motor (HSM). It’s a smooth and quiet system, but I did notice the 40mm performed slower than the 28mm Art. Again, because I was shooting these lenses on different camera bodies, I can’t say for sure if the 40mm itself was at fault. Still, the 40mm Art’s performance was strong, and most photographers won’t find flaw with its autofocus speed. Our TakeUnfortunately, removal is sometimes very challenging, and in some cases, flare effects can destroy image quality. Extension tubes are hollow lens barrels that shift a lens farther from the camera, allowing shorter focusing distances at the expense of long-distance focusing. The score in the “features-department” is 2[-]/5[0]/7[+], the most distinguishing features of the lens being its huge size and heavy weight – unfortunately. On a mirrorless body it looks and feels grotesquely unbalanced with the lens weighing twice as much as the body. On the positive side the lens seems well built and its coating and weather sealing should make for trouble-free operation under demanding conditions. Plus Sigma offers the unique option to get the lens-mount swapped. I think people who will most appreciate this lens are astrophotographers, for its edge-to-edge sharpness at wide apertures. Portrait photographers will also love it, although wedding and event shooters may find its size and weight hard to work with. With the right lens profile and software, lateral CA is often easily correctable (often in the camera) by radially shifting the colors to coincide.

Closest focus distance is 0.36m (14in.) in manual focus with a magnification of 1:5.6. This results in a working distance of 18cm when the lens hood is removed. A magnification of 1:10 is achieved at 0.55m distance. The Sony ZA achieves a similar magnification of 1:5.3 but the Zeiss Batis goes down to 1:3.1 at 0.24m with a working distance of 14cm. [0] You can also have a look at my comparison of Sigma 35mm 1.2 Art, 35mm 1.4 Art and 40mm 1.4 Art to see how these lenses compare. Mount an extension tube behind this lens to significantly decrease and increase those respective numbers.

crops from center, A7rII, because of focus shift (see corresponding section) I refocused for every shot Weighing in at 1.2kg and measuring 13.1cm in length, the Sigma 40mm F1.4 DG HSM is a massive lens given its focal length, signficantly larger and twice the weight of the very similar Sigma 35mm F1.4 DG HSM. Samples taken from the outer extreme of the image circle, full-frame corners, can be counted on to show a lens's weakest performance. The Sigma 50mm F1.4 DG DN Art Lens vs. Sigma 50mm f/1.4 DG HSM Art Lens comparison shows the DN lens is slightly narrower, slightly longer, and modestly lighter.