Out of Sigma’s freshly reorganised lens line-up comes a new ‘Art’-branded 50mm f/1.4 with claims of superb design and image quality. Richard Sibley puts it through our rigorous testing procedure to discover what truth these rumours hold
Sigma 50mm f/1.4 DG HSM | A reveiw – Image quality
The only surprise with the Sigma 50mm f/1.4 DC HSM | A is just how good it is. Having compared its test results to those of the 50mm lenses that we tested in AP 20 July 2013, the Sigma 50mm f/1.4 lens performs better than the twelve lenses in that test, in all areas and in every respect. At its centre, it is sharper than all of the other lenses, including the older Carl Zeiss Planar T* 50mm f/1.4, which was even tested on a slightly higher-resolution Nikon D600.
As can be seen in the images here and on the test chart, the lens performs at its best at f/5.6-8, and manages to resolve quite a staggering amount of detail. Even more impressive is the performance of the lens at its edges. At f/5.6 there is not much difference between the sharpness at the sides and centre of the frame, and it is only in the very corners that the quality drops. Again, it beats nearly all other 50mm lenses in this regard, although we have not yet tested the £3,500 Carl Zeiss Otus 55mm f/1.4, something that we hope to do in an upcoming issue.
Traces of chromatic aberration were noticeable in some raw images taken with the Sigma 50mm f/1.4 GD HSM | A, but this was only visible at 100% and was removed with the merest nudge of the slider in Adobe Camera Raw.
Tested on a Canon EOS-1D Mark IV
This set of graphs is one of the best that we have seen from any lens that has been through our new lens test. At f/5.6, centre resolution is better than in all of the 12-50mm lenses we tested in our round-up in AP 20 July 2013, as is vignetting. As can be seen in the shading diagram, the vignetting grid is almost flat, showing little difference between centre and edge brightness. The distortion graph shows slight pincushion distortion, whereas most 50mm lenses suffer from barrel distortion. However, it is so minimal that it should be of no concern. This lens is on a par with the best 50mm optics we have tested.