Some of our readers have been asking about the performance of the Sigma 50mm f/1.4 Art lens on the Nikon D810, particularly about its autofocus speed and accuracy, especially in low light situations. Lola and I recently shot a wedding with this combo and I had a chance to test out the lens in various conditions – from broad daylight to very dim indoor environments. In this article, I want to talk about my experience with the lens and talk about its pros and cons when using it with the Nikon D810.
There are three important aspects to talk about: autofocus speed, autofocus accuracy and color reproduction.
The Sigma 50mm f/1.4 has a very fast and silent “HSM” hyper-sonic autofocus motor. When compared to Nikkor primes like 50mm f/1.4G, the time it takes for the lens to snap into focus was noticeably faster, whether shooting in broad daylight or low-light conditions. In very low-light conditions when shooting indoors, the lens did occasionally get the camera confused resulting in failed focus acquisition, but using the center focus point and finding a more contrasty area to focus on seemed to help.
The Nikon D810 comes with the latest generation EXPEED 4 processor, which in my experience, makes autofocus noticeably faster when compared to EXPEED 3. Our team first noticed it on the D4S (when compared to the D4) and I noticed the same improvement in autofocus performance between the D810 and the D800 / D800E. This autofocus performance improvement is not only applicable for the actual speed of AF acquisition, but also tracking of subject movement. It feels like the D810 snaps onto the subject quicker and tracks movements noticeably better when compared to the D800 / D800E. By how much? It is hard to say, but our estimate has been somewhere between 15-30% better. You might not notice these improvements when shooting portraits, but if you shoot anything that moves fast (sports and wildlife, for example), you will surely feel the difference.
The Nikon D810 is not as forgiving as the Nikon Df / D4S and other lower resolution cameras. If you do not use a proper hand-holding technique and watch your shutter speed, the blur is going to be more visible at pixel level. So the first thing you need to get out of the way is potential blur due to camera shake. Once you get that out of the way, you can evaluate the AF accuracy of the setup. During my testing, I did not want to see any camera shake as a result of my hand-holding, so I set my “Minimum shutter speed” in “Auto ISO” settings to be one bar faster, which basically doubled the shutter speed. In the case of the Sigma 50mm f/1.4, it meant that my shutter speed was at least 1/100 and I found to be adequate in most situations when photographing the wedding.
During the wedding day, I shot with four different lenses – Nikkor 24mm f/1.4G, Nikkor 50mm f/1.8G, Sigma 50mm f/1.4 Art and Nikkor 70-200mm f/2.8G VR II. All three Nikkor lenses were pretty much nailing every shot – the keeper rate was above 90%, whether I was shooting still or moving subjects. Note that this is noticeably better than what I used to get with the D800E, which struggles with fast aperture lenses like 24mm f/1.4G. I was not the only person who noticed this – John Bosley also felt that the number of keepers increased significantly with the D810, as he reported in his D810 summary for wedding photography.
AF accuracy of the Sigma 50mm f/1.4 Art seemed to be a bit worse when compared to the above-mentioned Nikkor lenses. During the wedding, I noticed that the Nikkor 50mm f/1.8G was nailing almost every shot, while the Sigma 50mm f/1.4 seemed to struggle a bit in low light indoor environments. I felt like Nikon lenses were more consistent in this regard and performed better in low light. It is hard to say how much worse the Sigma was in comparison, but it is not by a big margin. When I compared the Sigma 50mm f/1.4 Art on the D810 to its older sibling, the non-Art Sigma 50mm f/1.4, AF speed and accuracy seemed to be noticeably superior on the Sigma 50mm f/1.4 Art.
This particular shot was the only sharp one out of a sequence of three images, captured in low light environment with a flash, while the bride was dancing with her father:
Looking at the images from the wedding, I am quite pleased by what I see in terms of colors – the rendering of colors looks good, I would say quite similar to what one would get with a Nano-coated Nikkor lens. Since the Sigma 50mm f/1.4 handles flare well, you don’t get a hazy / cloudy effect in images. So if you like backlighting your subjects with the sun, you can certainly do that without hesitation. Seems like Sigma did a good job with lens coatings – those certainly make a difference in difficult lighting conditions.
Also, the Nikon D810 seems to produce colors more naturally than the D800 / D800E. The latter cameras seem to saturate colors more (especially the greens), while the D810 does not do that. At first I thought it had to do with different white balance performance, but it turned out to be the sensor, since matching white balance still resulted in different colors.