A few weeks ago, ZTE had announced a new device in their flagship line-up, the new Axon 30. The phone is an interesting device for a few reasons: it’s one of the more rare devices this year that opted to use the Snapdragon 870 rather than the newer Snapdragon 888 chip, also pricing itself much more aggressively versus the higher-end Axon 30 Ultra which we reviewed also around a month ago.

What also makes the Axon 30 interesting is the fact that this is now the second-generation under-display camera implementation from ZTE. Although we never had the chance to experience the first-gen Axon 20, we’re now starting to see more vendors attempt to implement the new technology in their new devices, and the Axon 30 is a good opportunity to have a literal closer look at how these under-display cameras work.

ZTE Axon 30 Series
		Axon 30 Ultra		Axon 30
SoC		Snapdragon 888  1x Cortex-X1 @ 2.84GHz 3x Cortex-A78 @ 2.42GHz 4x Cortex-A55 @ 1.80GHz Adreno 660 @ 840MHz		Snapdragon 870 1x Cortex A77 @ 3.2GHz 3x Cortex A77 @ 2.42GHz 4x Cortex A55 @ 1.80GHz Adreno 650 @ ?MHz
DRAM		8/12 GB LPDDR5
Storage		128/256GB UFS 3.1
Display		6.67" AMOLED 2400 x 1080 (20:9) 144Hz 300Hz Touch		6.92" AMOLED 2460 x 1080 (20.5:9) 120Hz 360Hz Touch
Size	Height	161.53 mm		170.2 mm
	Width	72.96 mm		77.8 mm
	Depth	8.0 mm		7.8 mm
Weight		188 grams		189 grams
Battery Capacity		4600mAh 65W charging (PD3.0)		4200mAh 65W charging (PD3.0)
Wireless Charging		-		-
Rear Cameras
	Wide	64MP IMX686 0.8µm pixels (1.6µm 4:1 16MP) f/1.6 w/OIS 26mm eq.		64MP IMX686 0.8µm pixels (1.6µm 4:1 16MP) f/1.8 w/OIS 26mm eq.
	Main	64MP GW3 0.7µm pixels (1.4µm 4:1 16MP) f/1.9 35mm eq.		-
	Ultra-wide	64MP GW3 0.7µm pixels (1.4µm 4:1 16MP) f/2.2 13mm eq.		8MP f/2.2 13mm eq.
	Telephoto	8MP f/3.4 w/OIS (Periscope design) 120mm eq.		-
	Extra			5MP Macro 2MP DoF
Front Camera		16MP f/2.5		16MP (4MP 2.24µm) f/2.45
I/O		USB-C 3.1		USB-C 3.0
Wireless (local)		802.11ax WiFi-6E Bluetooth 5.2 LE + NFC		802.11ax WiFi 6 Bluetooth 5.1 LE + NFC
Other Features		Dual Speakers Under-screen optical fingerprint sensor		Under-screen optical fingerprint sensor
Dual-SIM		Dual nanoSIM		Dual nanoSIM
Launch Price		8+128GB: $749 / £649 / €749 12+256GB: $849 / £739 / €849		8+128GB: $499 / €499 12+256GB: $599 / €599

The Axon 30 as aforementioned is one of the rare devices this year released with the Snapdragon 870 SoC. As a reminder, the 870 is a higher binned variant of the Snapdragon 865 and 865+, this time increasing the CPU frequency on the fastest Cortex-A77 core to up to 3.2GHz – quite considerably faster than the 2.84GHz of the X1 cores of the Snapdragon 888, and still faster clocked than the 3GHz Snapdragon 888+. Due to the power efficiency regressions or non-progress of the Snapdragon 888’s manufacturing node, the Snapdragon 870 should still be a perfectly viable and competent SoC in a flagship device in 2021.

The device comes in either 8+128 or 12+256GB options, similar to the Axon 30 Ultra. Other device internals of the phone are a bit more conservative versus the Ultra variant, such as the lack of WiFi 6E, only USB 3.0 connectivity, and some notable features lacking such as only a single bottom-firing speaker.

The display is a very large 6.92” AMOLED at 2460 x 1080 resolution. It still features high refresh rate up to 120Hz, but even now increases the touch sampling rate to 360Hz to reduce latency and increase responsiveness.

The phone is extremely large; at 77.8mm width it’s considerably wider than even most “large” devices out there, and definitely dwarfs the Axon 30 Ultra. Because of the quite thin side frame design and curved back glass, as well as the quite thin 7.8mm body, the phone does still manage to have good handling and does feel smaller than what it really is.

The rear of the phone is defined by the camera setup: It’s mostly just a dual-camera device for all practical purposes. The main sensor is the same as on the Axon 30 Ultra, the IMX686 at 64MP resolution which bins down to 16MP 1.6µm in regular shots. The difference here is that the Axon 30 has a smaller f/1.8 aperture optics compared to the Axon 30 Ultra.

Alongside the main camera there’s also a small 8MP ultra-wide unit with f/2.2 optics. There’s also a 5MP macro and a 2MP DoF camera – but these are generally irrelevant for photography in most use-cases. In general, the Axon 30 evidently puts a much lower focus on the camera system than the Axon 30 Ultra.

The phone has one further pratical drawback compared to the Axon 30 Ultra and that is that it’s only featuring a single bottom firing speaker. The Axon 30 Ultra was able to use the earpiece speaker as a stereo unit, and although quality there wasn’t great at least it’s better than just a mono-speaker setup like on the Axon 30.

Naturally, the most interesting aspect of the phone is the fact that it’s one of the very rare devices today with an under-screen camera. While this isn’t ZTE’s first foray into the technology, it’s definitely a much more mature and interesting implementation we’ll be taking a closer look at.

The Axon 30 comes at much cheaper pricing than the Axon 30 Ultra, starting at only $/€499 – which very much puts it well below the usual flagship device price point, so we should adjust our expectations accordingly.

Under-Display Camera & Quality

Under-display cameras have been the holy grail of bezel-less display designs that every company is striving for. In the last few years, we’ve moved from camera notches, to hole-punch cameras, and today we’re seeing an increasing number of designs now attempt to commercialise the first or second-gen UDCs.

ZTE is partnering with Visionox to achieve the under-display camera implementation, a Chinese OLED panel manufacturer that we haven’t heard about too much to date.

Starting off with the subjective experience: how the UDC actually looks like and how good it’s hidden beneath the display: one has to note that while the implementation is quite remarkable, it’s still not quite invisible and fully hidden away.

The one aspect that I think betrays the UDC the most in everyday usage, is the fact that the “transparent” pixel area of the UDC appears brighter than the regular surrounding panel. It’s not a very large difference, but it’s always there on all kinds of colours and brightness levels, but is most noticeable on white. I have to wonder if ZTE would be able to correct for this brightness delta by simply creating a software overlay here that would calibrate things back down a bit – which would seem quite easy to do.

In darker scenarios, the transparent area of the panel is performing extremely well, however once the phone is in higher ambient light scenarios such as daylight, the UDC is more easily revealed. The easiest way this is visible is simply by looking at the panel from an angle, especially in sunlight. It appears here that the polarisation layer works well when the phone is looked at when in portrait mode, but has weaknesses in hiding the UDC at angles such as 45°. It’s not a practical issue, but just interesting to mention.

The above close-up has the panel turned off and we’re purely looking at the reflections of the underlying circuitry. Especially under a lot of light, the UDC is quite visible when the display is turned off.

What we see in terms of the circuit design is that things are extremely packed in the areas surrounding the middle “transparent” part, which only seems to have the actual OLED subpixels visible and non-transparent. Presumably what Visionox is doing is putting the supporting drive circuitry around the actual transparent panel “hole”. Unfortunately, I don’t have a microscope at hand to get a closer look at how exactly the structure here looks like.

The pixel matrix is evidently organised in vertical columns, however horizontally we see that there’s distinct repeating patterns of two different column types.

Once the panel is turned on, it becomes harder to observe the UDC as well as the general panel structure.

What’s quite interesting about Visionox’s panel UDC implementation is that it does not compromise on pixel density; we see the same resolution in the UDC area as on the rest of the screen. However, what does change, is the pixel fill ratio, with the UDC area having notably smaller OLED emitters compared to the regular panel. Generally, the higher the pixel fill compared to the background panel, the “smoother” a display will appear.

As we have also never seen a Visionox screen this close up, it’s also notable to remark the subpixel layout. The structure here is called a delta layout, a circumvention around Samsung’s patented diamond pentile structure that offers slightly less fill ratio and is a bit more regular (not what you want) as it appears that there’s 50°-pixel columns / non-fill gaps.

Camera Quality

While the UDC screen quality seems to be excellent, does the lower pixel fill ratio allow enough light for the front camera to be able to properly see through?

 
OpenCamera vs Stock Camera

Generally, the answer is no, however ZTE is making quite extensive use of software processing to be able to attempt to recover as much information as possible, and especially to counter-act some of the large optical compromises with the UDC.

Using a third-party camera app such as OpenCamera which doesn’t use any special post-processing shows just how bad the image quality out of the raw sensor is. What’s particularly evident here is the extremely large amount of ghosting and lack of natural contrast in the image. This is particularly visible if you have any kind of light source in the field of view of the camera.

ZTE’s post-processing is quite notable when you take a picture as it takes a second or two to kick in and be applied to the shot you’ve captured. After the processing, it quite a surprisingly competent job at eliminating the light ghosting as well as increasing the contrast of the scene. What’s not so good is that there’s a very large loss of tone gradations and it’s not very competitive in terms of dynamic range.

It appears that the camera here is capturing in the 4MP mode even though the camera outputs a 16MP image.

 
Axon 30 vs Axon 30 Ultra

Comparing the Axon 30 versus the Axon 30 Ultra, although the UDC is faring quite well, it’s evident that it’s nowhere near the quality of a regular front-facing camera.

 
Axon 30 vs Axon 30 Ultra

It’s mostly again the issue of what appears to be a inferior HDR implementation that is most handicapping the camera, as if it’s overexposing and then trying to reduce highlights too much, resulting in flatter tones.

Overall, the Axon 30’s key feature is interesting for people who actually do not use the front-facing camera much. The phone does a pretty good job of hiding it, and although not perfect, it’s amongst the best implementations we’ve seen to date. The camera, when needed, is still functional, however it’s clear that there’s a large quality compromise to be made when using it.

System Performance - Extremely Snappy

Featuring the Snapdragon 870, the Axon 30 should still be plenty competitive in terms of performance. The 120Hz screen and high touch sample rate also should allow excellent responsiveness.

The performance of the device in PCMark is excellent, and does end up managing to perform most of the time ahead of Snapdragon 865 devices (this is the first 870 we’ve had our hands on). What was a bit surprising is to see the Axon 30 outperform the Axon 30 Ultra in the writing sub-test, which could signify more aggressive scheduler settings on the Snapdragon 870 phone.

Unfortunately, ZTE is still doing benchmark detection and cheating in PCMark, increasing frequencies. We circumvent this in our testing.

Web Browser Performance

In the web-browsing tests, the Axon 30 lands in at around where we expected the Snapdragon 870, performing still quite excellently and keeping up with Snapdragon 888 devices, bar a larger gap in Speedometer.

Overall, the device is extremely responsive and the combination of 120Hz and high sample touch allows for a very snappy device experience.

GPU Performance

GPU performance should be a larger differentiator to the Axon 30 Ultra- the Snapdragon 870 should fall in line with Snapdragon 865+ devices such as the Note20 Ultra in our benchmark charts, however the end result will depend on the thermals of the device, notable because the Axon 30 Ultra was a device that was allowed to get quite hot.

The Axon 30 behaved quite differently to the Axon 30 Ultra, falling further behind in performance compared to its sibling. This difference however was not due to the inferiority of the Snapdragon 870 – but rather due to the fact that the Axon 30 throttles to peak skin temperatures of 39-40°C, significantly cooler than the 45-46°C of the Ultra.

The end result is actually a quite well-performing device that doesn’t get very hot, which is very much a positive in my book.

Battery Life - A Horrible Downgrade

With a 4200mAh battery, the Axon 30 has around 8% less capacity than the Axon 30 Ultra. The Snapdragon 870 is more power efficient than the newer Snapdragon 888 in our testing, so what that leaves out in terms of unknowns is the display panel from Visionox.

Unfortunately, in our web test at 120Hz, the Axon 30 falls face flat with one of the worst results of any device we’ve tested recently. The reason for this is I suspect the display panel. At 120Hz, the phone has a baseline black screen power consumption of around 800mW, and at 60Hz it’s still an abysmal 695mW, far above the norm of any other phone.

I don’t have confirmation on which DDIC vendor ZTE and Visionox are using here, but the behaviour here reminds me of the horrible power consumption characteristics of LG and BOE screens of the past.

The more SoC and CPU bound PCMark tests allows the Axon 30 to narrow the gap a little more as the display plays a smaller percentage of power used, and while adequate, it’s still quite behind the Axon 30 Ultra and other competing devices.

Generally, the battery life here is very likely tied to the choice of display panel provider as we’ve seen this story repeated quite a lot over the years as third-party OLED vendors besides Samsung Display struggle to achieve power efficient panels and DDIC solutions.

Conclusion & End Remarks

The Axon 30 is an interesting device, both in terms of specifications and also in terms of product category. First and foremost, I had to keep reminding myself that this is a $499 phone, and that’s also a quite important aspect of the device for US readers who usually have extremely little options in that price segment.

Design wise, it’s a relatively generic phone that’s more defined by its size than anything else; with a 6.92” display and 77.8mm body with, it’s a large footprint phone even though it manages to keep things quite reasonable at 189g. Build quality is decent but generally below that of the smaller, higher-end Axon 30 Ultra – which is actually not much of a surprise.

Performance of the phone is great, thanks to the still very competent Snapdragon 870 chip. Peak performance isn’t at S888 levels, however this chip is more power efficient and manages to keep the device cooler than the Axon 30 Ultra.

The defining characteristic of the device is the under-display camera and the screen by Visionox which enables it. There are two large conclusions to be made here:

Firstly, the visual implementation of the UDC is amongst the best we’ve seen so far. While not perfect, the phone manages to hide its under-display camera extremely well. If ZTE manages to even out the brightness differences between the UDC area and the regular panel when viewing the phone head-on, I would say that essentially, you’d be hard pressed to see it anymore.

From a camera quality perspective, I had low expectations, but I was actually still surprised at what ZTE managed to achieve thanks to software processing. Essentially, the camera acts as a 4MP unit, which is quite low res, so you should not really expect great details. Dynamic range and textures are also quite below the norm, however compared to the raw output of the camera, you can’t help but respect the image processing that the phone is achieving.

Overall, if you’re the kind that looks to hide away the front camera to achieve the bezel-less look, I think the Axon 30 is a success. If you still value camera quality – we’re not quite there yet.

The second conclusion of the UDC is related to the display panel itself. It’s the first time we’ve tested a Visionox panel, so I wasn’t sure what to expect, but I had rather low expectations. In terms of brightness, the panel is extremely competitive, however that’s about it when it comes to the positives. The panel differs quite a lot from the usual OLED contenders – when looking at it from extreme angles you can see the polariser shimmering in viridescent colours, something I haven’t seen in many years. The pixel layout, while not exactly visible to the eye, also does feel somewhat less sharp than the regular diamond pentile we’ve gotten used to from Samsung.

One could live with the aforementioned aspects; however, the large deal-breaker is the unsatisfactory power efficiency of the panel. At 423nits brightness, the phone uses 2.87W of power, which is significantly worse than Samsung Display OLED panels (S20U – 2.4W, S21U, 1.8W) Much like the many phones that got ruined by inefficient displays in the past, it also looks like the Axon 30 is also suffering from a larger battery life hit due to the display.

Given the choice of a UDC with an inefficient screen, or a hole-punch with an efficient screen, I’d always choose the latter.

Overall, I think the Axon 30 is an interesting phone, but I can’t help feel it’s still more of an immature technology showcase rather than a refined product. I think the Ultra sibling is still a much better phone, but at least ZTE is pricing the Axon 30 at a quite reasonable level.