Nikon Z 6II: What are the benefits of two processors?
1.12.2020
Translation: machine translated
Two processors instead of just one: how does this affect the performance of the camera? I tried it out with the Nikon Z6 II and am not particularly impressed.
The new Nikon Z 6II and Z 7II each have two Expeed image processors. I want to find out what this really achieves with a few tests.
Everything twice as good?
Nikon writes on the product page of the Z6 II: "Two Expeed processors double the available performance - from autofocus to buffer capacity." It doesn't say much more about the processors, but it sounds pretty impressive. Let's take a look at it.
The buffer memory is indeed impressive and does not limit me in any way when taking pictures. According to Nikon, it holds 200 JPEGs or 124 RAW files. This is a significant improvement on the Z6 with 47 JPEGs or 35 RAW files.
On closer inspection, it turns out that these specifications only apply to RAW files with 12-bit colour depth. A 14-bit RAW is about 25 per cent larger, so the buffer lasts less.
Let's move on to the continuous shooting speed. The data sheet already shows that the performance is by no means doubled. The continuous shooting speed of the Nikon Z 6II is a maximum of 14 photos per second. The Z6 with only one processor achieves 12 fps. Both values apply to JPEG and 12-bit RAW. With 14-bit colour depth, it is 10 and 9 images per second respectively.
I don't know why more doesn't come out. However, it seems obvious to me that the two processors have to coordinate their work, which leads to losses.
The autofocus
The autofocus should work faster thanks to the two processors. This makes sense, because recognising and tracking the subject requires a lot of computing power. Eyes and faces have to be recognised almost in real time. In addition to the image processor, the Nikon D850 has a separate processor for autofocus tracking. This means that the Z 6II and Z 7II are not the first cameras with two processors - but they are the first to double the existing processor.
But is the autofocus twice as fast or twice as good because of the two processors? Of course not. For one thing, speed depends on more than just computing power. For another, there are also likely to be losses due to the tuning of the two processors.
What does "twice as much performance" mean for autofocus? How can it be measured? I have no idea. I think the statement is nonsense for that reason alone.
Since I can't measure the autofocus performance, I rely on my gut feeling. This tells me: there is progress, but it's not a quantum leap. Even with the first Z6 I managed to take some good animal photos. At that time I was still using the adapter for SLR lenses. I used the following combination with the Z6 II:
The tracking is usable in many cases, but it fails with subjects that move quickly and unpredictably. With seagulls in flight, I had no chance of moving the tracking field to the right spot quickly enough. With slower subjects like a swan, it worked well.
However, this has nothing to do with the processing power. Rather with the operating concept. However, if the camera automatically recognises the eye or face, there is no need for tedious positioning of the tracking field. However, this only works with people, dogs and cats. It does not work with birds.
Of course, I can do without tracking and switch on the fully automatic autofocus instead. Then I have no stress, but also no control over what is focussed. Without face detection, the camera usually focuses on the closest subject. That's not always right.
In my opinion, the eye and face recognition works well for people. Unlike the Z6, it is also available for video recordings.
In addition, the Z6 II allows you to select an image area for face detection and thus exclude certain areas from focussing. Also nice: if the camera recognises several faces/eyes, this is indicated by a small arrow. Pressing the corresponding arrow button switches to the next eye or face.
The tracking sensitivity and AF speed can be adjusted. In the video above, I set the speed to high because I wanted to test the responsiveness. However, this looks far too nervous - I would set it slower for a serious shot.
Although this works perfectly, I have the impression that the Sony face detection works a little faster. The Canon EOS R5 also seems slightly better to me. But that's a subjective impression that can't be backed up with figures.
Video and overheating
The Z6 II can currently only record 4K videos at 30 fps, just like its predecessor. However, this is set to change with a firmware update, which has been announced for February 2021. Up to 60 fps will then be possible. That would actually be twice as good.
This means that the hardware is basically equipped for 4K60. And this must be due to the dual processor, because the sensor is the same as in the Z6.
The question is how quickly the camera overheats. I suspect that a camera with two processors will heat up less quickly when performing the same task. I imagine that the heat development is distributed over two locations and therefore there are fewer extreme values.
As the camera is not yet capable of 4K60, I am unfortunately unable to test it. However, to get an impression, I run 4K30 and Full HD at 120 fps in continuous mode.
The clip length of the Z6 II is limited to 30 minutes. In terms of heat development, however, this would not be necessary. I can record four clips in a row in both recording modes, i.e. a total of 2 hours each, without a warning or automatic switch-off. I haven't tried any longer than that.
According to this report, the predecessor Z6 only runs for just under an hour under similar circumstances. Unless Nikon has made significant changes to the cooling system, the dual processor has a favourable effect on heat development. However, the camera still has to pass the endurance test at 60 fps.
Battery life
Two processors consume more power than one. At least if they actually perform better. A negative effect on battery life is therefore to be expected.
This is also difficult to measure precisely, as battery life depends on countless factors. I can say with certainty that the two processors do not need twice as much power. Nikon has also increased the capacity of the battery. The new EN-EL15c battery has 2280 mAh and is backwards and forwards compatible with the older EN-EL15b (1900 mAh).
A half-day photo session is no problem with one battery. Depending on the situation, it can also last for a whole day. The two-hour video endurance runs required a battery change.
For marathon performances, this camera can also be connected to the mains via USB-C. There is also a battery grip that allows the battery to be changed during operation.
Conclusion: Not bad, but not twice as good
The claim that with two processors there is simply twice as much power available is rubbish. The big wow effect doesn't materialise. The advantage in terms of speed is small. The - presumably - more favourable heat development is more significant. However, the endurance test with 4K60 is still pending. It is pleasing that the battery does not drain noticeably faster than with just one processor.
I can't say to what extent this can be generalised and applied to other brands. But I very much doubt that two processors will be installed everywhere from now on. After all, two processors cost more than one. <p
David Lee
Senior Editor
David.Lee@digitecgalaxus.chMy interest in IT and writing landed me in tech journalism early on (2000). I want to know how we can use technology without being used. Outside of the office, I’m a keen musician who makes up for lacking talent with excessive enthusiasm.