Friday, 6 December 2013

Nikon's new 58mm F1.4g is a disappointment

If Nikon's aim was to better Sigma's 50mm f1.4 and Canon's 50mm f1.2 with the new 58mm f1.4g then I think Nikon has probably succeeded. Tests indicate that the new Nikon beats the Sigma as far as Coma correction is concerned. See the links below for comparative tests carried out by Thomas Rubach - whose lens tests are published by CameraLabs.
The new 58mm is also superior to Nikon's 50mm f1.4g, which exhibits significant coma at f1.4 as evidenced below, again thanks to testing done by Thomas.
Clearly the 58mm is an improvement. My disappointment though stems from the fact that Nikon has claimed that Sagittal coma flare is effectively minimised across the entire frame with the result that point light sources such as city lights are reproduced as fine rounded points, even at the periphery of the image, enabling unparalleled nightscapes. Yet clearly as demonstrated by the test above, this is not the case. Even Nikon's own sample below exhibits coma at the edges were point light sources are distorted.
If the Zeiss Otus 55mm f1.4 had not been present, we might have consoled ourselves with the thought that perhaps it was not physically possible to do better than what the 58mm f1.4 achieves in coma correction. Except that the Zeiss Otus is better corrected for coma than the Nikon as can be seen in example below (again from Thomas Rubach's testing):
Not only is the Zeiss better corrected for coma, it is also much sharper. 

The question is in what way can the 58mm f1.4g be justified, given its price tag. If one wants the best performance then clearly the Zeiss Otus is the undisputed choice. If better bokeh is desired then perhaps the 85mm is a better focal length anyway.