The new iPhone XS and iPhone XS Max appear to smooth out skin and reduce shadows and other details in photos taken with its selfie camera.

The effect is pretty similar to "beauty mode" on other phones and apps.

Popular YouTube channel Unbox Therapy made a video about it and called it "beautygate."

Apple declined to comment.

One of the big selling features on the new iPhone XS and iPhone XS Max is the 8-megapixel front-facing selfie camera.

According to Apple, the selfie camera system on the iPhone X uses faster sensors, improved chips, and "advanced algorithms" to make your photos look better with a feature called "Smart HDR."

But some people who have received the new iPhone XS say that the new selfie camera makes them look too good — so good that they think Apple must have added a "beauty mode" filter to the camera's algorithms to smooth the subject's skin.

Beauty mode is a feature on a lot of phones and apps that are popular in Asia, like Samsung devices or apps like Meitu or FaceTune. It smooths out and brightens your skin so you look a little more polished on social media.

And now dozens of commenters on Reddit, MacRumors forums, and even popular gadget YouTuber Lewis Hilsenteger, known as Unbox Therapy, are theorizing that Apple must be automatically doing it on the new iPhone, given how their selfies look.

"I am so frustrated with this camera. I look stupid in snaps. It looks like I’m using an air brush filter," Redditor gray_13 posted.

"I just got my phone and love it, but when I opened the camera app to the front facing camera, my face looked like it had a Snapchat filter on it. My skin looks too smooth," w_illiam_ilson posted last week.

"It looks like I'm wearing foundation," Hilsenteger observed in a video posted on Wednesday, after trying the camera with the HDR feature turned on and off. He called the phenomenon "beautygate."

Here's his side-by-side test:

Selfies taken with iPhone XS and iPhone XS Max are in the middle. iPhone X on the left, and iPhone 6 on the right. YouTube/Unbox Therapy

"So it looks like, whatever processing is going on here, with the facial recognition, and this smart HDR and whatever extras are there — because it's even happening with Smart HDR turned off — is resulting in this almost covert beauty mode, this secret beauty mode," he speculated.

A Redditor's comparison shot. Reddit

But would Apple really introduce a beauty mode? It's not a feature listed on Apple.com, unlike other camera features like Portrait Mode, which Apple says can use machine learning to distinguish faces in the photo.

Apple declined to comment on the record when reached by Business Insider, but some people on the Reddit and MacRumors threads say the effect people are seeing isn't a beauty filter, but is instead part of the new iPhone noise reduction capabilities.

Aggressive noise reduction causing the phenomenon is also a theory advanced by Apple blog Cult of Mac,

When smartphone cameras take photos in low light, they introduce what's called "noise," or little bits of grain across the photo. Noise is one of the biggest problems with smartphone cameras because they have smaller lenses and sensors that can't let in as much light as professional rigs.

Apple's camera isn't just a camera — it's an entire system, and improvements to the system's chips have allowed Apple to reduce noise in photos, the company briefly mentioned when it launched the new iPhone XS. A beauty mode in the Meitu app. Kif Leswing

Sebastien Marineau-Mes, an Apple VP of software, also mentioned the improvement when speaking with journalist Lance Ulanoff.

"We set a reference frame and fuse in information from multiple frames," he told Ulanoff, referring to how the HDR features combines multiple photos to make one better photo.

"As you stack the frames, if you have the same image, you have lower and lower noise and better and better detail," he continued.

This suggests that perhaps if a photo is taken with more light, the smoothing would appear less prominent. A test run on Thursday in natural daylight did show a less pronounced smoothing effect.

Apple is unlikely to force a so-called "beauty mode" on iPhone camera users — after all, if people really want to apply filters like that to a photo, they can download any number of apps that do it, like FaceTune, which is one of the best-selling paid apps in the App Store.

Still, beauty filter features are popular in Asia, a region where Apple needs to excel to justify its $1 trillion valuation, even if the effects from apps like Meitu are far more pronounced than what online observers say is happening on iPhones.