With a wealth of external controls that put nearly any shooting adjustments a button-press away, the D610 is a nimble camera to operate. The on/off switch is placed around the shutter button for easy one-handed operation and powers on nearly instantaneously (about 0.13 seconds) so you're never waiting for the camera. Accessing menus systems is also quick using the eight-way controller. It has a vast array of custom settings and buttons, along with two custom setting banks that allow you to configure the camera any way you like.
At 6 fps, the D610's continuous shooting speed and buffer capacity is more than enough for most situations (see below for tests). Only dedicated sports or wildlife photographers may want faster speeds for critical work.
The capable 39-point AF is easily and directly accessible via the eight-way controller. AF quickly locked in on targets in most environments we shot it. Like many cameras, it only started to struggle in low-contrast, low light situations or when using lenses at maximum aperture.
The new shutter mechanism in the D610 increases the frames-per-second from 5.5 to 6. And when in the new Quiet Continuous mode, you can fire away at 3 fps. At 6 fps the D610 tops the D800 and stays on pace with the D7100. Compared to its competition, it beats out the Canon EOS 6D, but is still slower than the smaller sensor EOS 70D.
Dual SD card slots are found on the D610 and these can be configured to capture images in a number of useful ways, such as overflow and duplicate storage. When shooting in RAW+JPEG mode, raw files can be saved to card slot 1, with JPEGs recorded to slot 2. You can also shoot single shot images and access camera menus and shooting options while data is still being transferred to the card (as we'd expect with a camera of this price).
For the timing tests below we used a SanDisk Extreme Pro 16GB Class 10 UHS-I SD card (95MB/s). Active D-Lighting and lens distortion correction were disabled. Raw file output was set to the camera's default 14-bit, lossless compression settings.
FX Mode: Continuous Hi
The D610's 39-point AF system is inherited from the D7000. It's the same one found in the D600 and the Nikon Df. Although it's not as good as the 51-point AF system with 15 cross-type sensors found in the D7100 or D800, overall it's a capable system for most situations. The D610 comes with nine cross-type sensors in the center area and can configured in a variety of the usual Nikon AF modes: single-point, dynamic-area (9 points, 21 points, 39 points), 3D-tracking and auto.
As mentioned in our D600 review, the centralized AF coverage area may be a sticking point for sports or wildlife photographers. Since it borrows the same AF system from the D7000, a DX format camera, the D610's AF points are clustered more toward the center than its D800 full-frame sibling. Shooters using the D610 along side their D4 or D800 will most likely notice this difference quickly. This bias for the center area is also seen in the Canon EOS 6D.
Depending on your subject, one way to minimize this limitation is to use the "focus, recompose" technique or set the D610 to its DX crop mode. This reduces the size of the frame allowing the AF area to cover a larger proportion of the scene and produces a very usable 10.5 MP file.
In bright sun or high contrast situations the D610, like nearly all cameras, AF is excellent. Where the D610 AF system starts to be challenged is in low-light or low contrast scenes, but this is not uncommon for most AF systems. In my time shooting with the D610, I found the low-light AF performance working well enough that I didn't have to change my shooting habits or compositions.
Overall, subject tracking performance with the D610 is good when shooting in continuous drive mode. However, there are situations where the D610 may cause some doubt in accuracy. In the example below we set the camera on 3-D tracking AF-area mode and followed the on-coming bicyclist with the outer right most AF point. As you can see in the 6-frame sequence, the D610 locks focus in the first two frames, but in frame 3 it completely blows focus on the subject. Frame 4 is usable, but at 100% the image is still soft. By frames 5 and 6, the AF has relocked on the subject.
In the course of our testing, we found greater AF acquisition consistency using with the center-9 AF points that have cross-type sensors than using the outer AF points. In the example below, the D610, in 3-D tracking AF-area mode, locks onto another bicyclist that is moving toward the the camera in the center of the frame. Despite any concerns with the outer AF points, the D610 is still a proficient camera for tracking moving subjects. It should be noted that our testing is limited in scope and you should test the D610 in the situations you're likely to be shooting the most. These were shot with the Nikkor 70-200mm F4 lens.
Shortly after the D600 was released in late 2012, some users reported a more than usual build up of dust and/or oil residue on the sensor, and we investigated this in our original review. Nikon responded by urging users experiencing this issue to send their cameras in for professional servicing, and only acknowledged 16 months later, that the D600 was prone to this problem. Although the company still characterizes the problem as a build-up of 'dust particles,' it appears that oil from the shutter mechanism could spit onto the sensor, making it hard to remove any dust that then stuck to it.
What we do know is that the D610 was released just a year later with a new shutter mechanism and, although in our time with the camera we found some dust and/or oil residue build-up, it was not a significant problem. Dust did accumulate on sensor after normal use, which included multiple lens changes and people handling the camera in a variety of conditions. However, a few pumps from our Rocket Blaster blew off most particles we found.
Below, is an image from just before we cleaned the D610's sensor with a Rocket Blaster. It's about 7,770 frames after the the last time we blew any dust off. As you can see there is a good amount of dust in the upper left of the frame. The second image shows the result of the our Rocket Blaster efforts. The image is much cleaner in the upper left region, but still has some spots. So, although the new shutter mechanism can still see dust getting stuck to the sensor, overall it doesn't appear to be the same amount being reported from some D600 users, and not enough for us to say there is a significant 'issue.' It should be noted that many other D610 users and reviewers have also concluded the problem has been resolved.
The D610 uses the EN-EL15 rechargeable battery, the same one used on the D800 and D7100. CIPA estimates about 900 shots per charge. We found we could go through a full day of shooting with regular use of the LCD and still have more than enough charge remaining. In our interval timer test, with no LCD use, we got more than 3,300 shots before the battery ran out. We found this very impressive.