Google Explains Decisions Made for Pixel 2 Camera: High ISO in Videos, 4K/60FPS, RAW and Manual Modes, and More

By | 20th November 2017

The Google Pixel 2 and the Pixel 2 XL may have faced their share of issues, but one thing which has not been a source of issue is their cameras. Their 12MP camera with fused video stabilization has been acclaimed by many to be currently the best smartphone camera, with excellent image and video quality. However, that doesn’t mean that the Pixel 2’s camera is perfect, as many features such as Pixel Visual Core are yet to roll-out; they will be enabled in future software updates.

To clarify some of the issues and doubts they had with the Pixel 2’s camera, NDTV Gadgets had a Hangout session with Brian Rakaowski, VP of Product Management at Google and Timothy Knight, who leads camera development for Pixel 2.

The first issue faced by NDTV Gadgets was that the Pixel 2’s 4K low light video is noisy. Mr. Knight from Google explained that this is intentional as the Pixel 2 tries to brighten up the scene as much as possible by using a higher ISO. This has the effect of having a brighter video, at the cost of an increased amount of noise.

That is a tradeoff we think a lot about. We tried to strike a balance of the two. If you compared the Pixel 2 camera to other mobile cameras, you’ll see that we’re brighter. It’s easy to make the noise go away if you just make the image dark. We decided that we rather let the user see the scene more clearly, by making it brighter, even if that means there is some more noise.

He added that 1080p video from the Pixel 2 should be a bit less noisy compared to 4K. This is because there’s more headroom to do heavy weight processing in 1080p as compared to 4K.

Another related issue is that the Pixel 2 can’t record 4K video at 60FPS. The iPhone 8 / 8 Plus and the iPhone X do have 4K-60fps capability thanks to the A11 SoC. Mr. Knight stated: “4K at 60[FPS], unfortunately, is not something we’re going to bring to Pixel 2. For future products, we’ll consider it certainly. But for Pixel 2, 4K30 and 1080 60 is the video we plan to support.” The statement implies that the next Pixel phone may have 4K60 support. The limitation for the Pixel 2 is because of the Qualcomm Snapdragon 835 SoC, which does not support recording 4K video at 60FPS.

Moving on, enabling manual control for HDR+ in the settings of the Pixel 2’s camera app gives users a second option in the camera preview: ‘HDR+ enhanced’. This was known as ‘HDR+ on’ in the first-generation Pixel. NDTV Gadgets 360 stated that when they tested the Pixel 2 and the Pixel 2 XL, they didn’t notice any quality difference between the two modes, other than the fact that it takes longer to process the HDR+ enhanced photo.

Mr. Knight’s response was to state that there is no difference in quality in the large majority of cases. HDR+ and HDR+ enhanced will “take the same photo from a user perspective. He noted that in a small number of conditions, HDR+ enhanced can take a photo that has slightly more dynamic range. The reason that HDR+ enhanced mode longer to process is because in standard HDR+, Zero Shutter Lag (ZSL) is on. On the other hand, it’s disabled in HDR+ enhanced. As ZSL results in photos taken with almost no delay, this means that HDR+ enhanced is naturally going to be at a disadvantage here.

NDTV Gadgets 360 assumed that the Pixel Visual Core imaging chip would help speed up the process of ‘HDR+ enhanced’ photos, but Mr. Rakaowski confirmed that this would not be the case, even when the chip would be enabled in Android 8.1. The Pixel Visual Core’s primary purpose will be to enable third-party camera apps to use the HDR+ feature through the camera API. (In Android 8.1 DP1, developers still can’t test HDR+ through the Visual Core; it is said to be enabled in the next developer preview).

Finally, Google also explained the rationale for the lack of manual controls and RAW file supports. Other Android manufacturers have included manual controls through the years, with sliders for ISO, shutter speed, focus distance, exposure compensation, and more. Most users do not need manual controls, but the choice to have the option is good.

Mr. Knight stated that simply putting sliders for ISO, exposure, and so on is not the best interface for a phone. He added that if Google added a manual mode, users who used it would not be able to take advantage of HDR+, which is the set of techniques used by Google to get excellent image quality from its smartphone cameras. Therefore, the image quality would deteriorate.

Mr. Knight said that Google may add some level of manual control in the future,  but people “[shouldn’t] expect to see a manual slider anytime soon“. Google is relying heavily on its machine learning and computational photography, and therefore the company isn’t willing to have a manual mode in its camera app, which would defeat the purpose of auto HDR+.

The same is applicable for the ability to shoot in RAW in Google Camera itself. Mr. Knight stated that the company has received similar feedback about the ability to shoot in RAW from other users as well. He concluded by stating that they didn’t have any updates as of now, but the company was looking into it.

Overall, the report was illuminating as we got to understand several decisions and tradeoffs which Google made with the Pixel 2’s camera. Ultimately, the decisions taken don’t make the Pixel 2’s camera sub-standard, but they do help prove that there is a still a long way to go in terms of improvement for smartphone cameras.

Source: NDTV Gadgets