Autofocus Performance
As I have already pointed out, I have received a number of requests from our readers, asking me to thoroughly assess the autofocus performance and accuracy of the Nikon D600, especially when compared to the Nikon D800/D4. Since the D600 uses a very similar phase-detect AF system as the Nikon D7000, the big question is if there is any AF performance difference between the two. I split the answer to multiple sections, since people are considering the D600 for different environments.
Autofocus Performance: Daylight
In daylight situations, the AF performance of the Nikon D600 is excellent. I was able to obtain accurate focus on my subjects most of the time and I honestly could not tell a difference in AF performance between the D600 and the D800. I used lenses like Nikon 24mm f/1.4G, Nikon 50mm f/1.8G, Nikon 24-70mm f/2.8G and Nikon 70-200mm f/2.8G VR II – all worked very well without any issues. Daylight conditions are not really a challenge for most modern autofocus systems though – even entry-level DSLRs like Nikon D3100 do quite well when there is plenty of light. It is obviously a different story when photographing fast moving subjects or in low-light environments.
Autofocus Performance: Low-Light/Indoors
All AF systems start to suffer in low light situations, simply because very little light gets to the phase-detect sensor (as explained in my “how phase detection autofocus works” article). In my experience, autofocus systems in full-frame cameras always seemed to outperform autofocus systems in cropped-sensor cameras, especially in low-light situations. For example, I had a lot more “keepers” with the Nikon D700 than I did with the Nikon D300/D300s. Since Nikon reused the 39-point AF system from the D7000 (MultiCAM 4800) on the D600, my first task was to see if there is any difference in AF performance between the two. After testing the AF system of the D600 alongside the D7000, I came to the conclusion that the MultiCAM 4800FX AF system is more accurate than the MultiCAM 4800DX AF system on the D7000, especially in low-light situations. While AF speed seems to be about the same on both, the D600 does not hunt for focus as much as the D7000 does and the hit/miss ratio is much better.
Autofocus Performance: Wildlife and Sports
I had a chance to do a rather demanding test on the Nikon D600’s AF system, photographing Colorado wildlife. I wanted to see if the camera would be suitable for photographing sports and wildlife since many of our readers have asked me to do that in the review.
I started out photographing birds first. Small birds can be tough to photograph since they move constantly and they fly fast. My primary subjects were Clark’s Nutcracker and Steller’s Jay – both were very active, so they were perfect for testing the speed, responsiveness and reliability of the AF system of the D600. I started out in AF-C mode, Ch release, Dynamic 39 points and Focus Tracking with Lock-On set to 3 (Normal). Focusing on perched birds was very reliable and I got a lot of keepers. I even used other focus points in the extreme corners while composing my shots and the images came out in perfect focus. However, the moment a bird would take off, I had a hard time tracking it in flight with my Nikon 200-400mm f/4 VR (hand-held), since they were too fast. Very often they were too close and too fast, which made it harder to get anything in the frame and in focus. Gladly, I was not the only person having this problem – Tom was standing right next to me with his Nikon D4 and Nikon 500mm f/4 VR and he was having similar issues. So I knew it was not the camera at fault.
Having photographed birds with the Nikon D3s before, one thing that I really enjoyed about the D600 was its new Auto ISO implementation with an “Auto” value for the “Minimum Shutter Speed” (previous generation cameras do not have this feature). When photographing birds, I set my shutter speed to be double the speed of the focal length and it worked out great. And when I needed to go faster than that, I set the “Auto” value to +2 (Faster) and my shutter speed would be tripled (3 full stops), giving me enough speed to get fast action. The nice thing about this setting is that I went back and forth between 200mm to 400mm and the shutter speed would be compensated automatically. At 300mm, setting Auto to +2 would give me 1/1250 shutter speed, which was often good enough for birds in flight. However, when I needed to go faster, I would switch to the desired shutter speed instead. I turned off VR most of the time, since my shutter speeds were fast enough.
As you can see from the images here, the Nikon D600 did really well with perched birds. All images posted here are very sharp and you can see individual feathers on birds at 100% view (none of the images were taken to Photoshop – these are crops out of Lightroom, with little sharpening applied upon export). Both the D4 and the D600 had a hard time tracking fast little birds in flight with Dynamic AF, so Tom and I both switched to 3D AF mode, with Focus Tracking set to 1 (Short). We then both started to get some shots of birds in flight in focus and the hit/miss ratio started to get better. My biggest challenge was to try to keep birds within the smaller AF zone (which is smaller on the D600). Overall though, the Nikon D4 still had the edge as far as AF performance and accuracy in my opinion. But I cannot say that the D600 was much worse either – it performed surprisingly well in this environment.
After photographing birds for about an hour, we took off to take some pictures of bighorn sheep and elk:
The detail level on each image is very high. Take a look at the below image of the Male Elk:
And here is a 100% crop:
Lastly, I took a couple of pictures after sunset of a running female elk. The first image was shot at ISO 3200 and the second one was shot at ISO 1600. Both images have plenty of detail and very acceptable noise levels.
If you shoot at higher ISO values, you might want to run some noise-reduction before you down-sample the image to get the best results.
Overall, I am quite impressed by what the D600 can offer to sports and wildlife photographers. While the AF system is not as robust as the one on the D4/D800, it is still a very good AF system that is far better than the one on the D7000 in my opinion. I have not performed any tests with Nikon teleconverters, but I am sure they will work just as well. More to come, since I am planning to visit Bosque Del Apache later this year and use the D600 for bird photography there!
Autofocus Performance: Landscapes
The Nikon D600 does quite well for photographing landscapes, but you do not really have to worry about AF performance/accuracy for landscape photography. If you shoot on a tripod, I would rely on the much more accurate contrast detect using Live View mode instead. You can also switch your lens to manual focus and use Live View while zoomed in to 100% to get the most accurate focus (see more on the Live View implementation below). During my fall landscape photography trip this year, I mostly relied on contrast detect via Live View for sunrise/sunset shots when I mounted the D600 on a tripod. During the day, however, I focused normally hand-held with Phase Detect and everything worked as expected.
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