Hidden features of the iPhone are exposed: finding bugs for pets. We gave it a try.

In the past two days, if you see someone rummaging through their dog's or cat's fur, making them open their mouths and spread their legs, and then taking a 360 - degree crazy photo with their phone. After taking the photo, they frown and stare intently at the strange photo on the screen for a while.

Don't be nervous. This is not animal abuse. Most likely, this person is using an iPhone to check if their pet has bugs.

iPhones can detect bugs, and Android phones have similar functions

This hidden function was discovered by netizens on Xiaohongshu.

On June 26th, a blogger who owns a dog posted a video saying that the built - in magnifier on an iPhone can quickly check if a dog has bugs.

The specific operation steps are to search for "Magnifier" on the iPhone and click to enter, then click "Filter" and select "Invert".

Then take a photo of the dog's fur. The areas with bugs will be unusually bright.

The blogger also mentioned that this method is particularly suitable for two types of pets.

One type is those "furry kids" that have a strong reaction to internal deworming, have little effect with external deworming medicine, and especially like to drill into the grass.

The other type is applicable regardless of the pet's coat color. When using it, you don't need to care about how the pet's fur looks in the filter. Just rummage through the roots of their fur, and the bugs will definitely be bright, making them easy to spot at a glance.

Actually, not only iPhones, some Android phones also have similar functions. For example, on OPPO or vivo phones, search for "Invert" in the phone's "Settings". After turning on this function, it can achieve the same effect.

This topic instantly caught the attention of many pet - owning netizens. They all joined the army of looking for bugs, and it even became a hot topic on Weibo.

In the photos of cats and dogs they shared, some were very strange, and some were like "cat life photos" taken with Polaroid - like effects.

Some people made jokes when they didn't find the right area while looking for bugs.

Some people were sitting in the office. Unable to hold back their curiosity, they grabbed their phones and took a photo of their colleagues next to them. Does this count as a work - related injury?

Netizens' creativity doesn't stop there. Some people used this function for checking banknotes by analogy, and they can also detect hidden cameras after setting the filter to red.

Editor Ke tested both iPhones and Android phones and found that both present details clearly. The pet's fur becomes distinct, and the ear canals are more transparent.

The biggest difference between the two lies in the operation.

iPhones can directly take photos, and users can view the details of the pet's fur through the photos.

Android phones turn on the system's invert mode. After turning off this mode, both screen recording and taking photos will show normal images. So users can only watch the phone screen while taking photos or turn on the invert mode again after taking photos to view.

Is it a gimmick or really useful?

In response to the heated discussion, Apple customer service staff replied that the function of the magnifier is to allow Apple users to magnify some small things. However, Apple has not admitted the function of using the magnifier to check bugs mentioned online.

However, in principle, this function has certain practicality for both iPhones and Android phones.

The magnifier function essentially optically or digitally magnifies an object through the camera, allowing us to observe the details more clearly.

The invert function reverses the color and brightness relationship of an image. Originally dark objects will become light after inversion, and the light background will become dark, thus enhancing the visual difference between different objects.

In the scenario of looking for bugs on pets, parasites such as fleas and ticks are usually dark - colored, like dark brown or black, while most of the pet's fur is light - colored or has a light - colored background.

When we use the magnifier to zoom in on the fur area and turn on the invert function, the contrast between the dark bugs and the light - colored fur will be greatly enhanced, making it convenient for the owner to find them.

But for tiny light - colored bugs, this function may not be as useful.

As for checking banknotes, some anti - counterfeiting features of banknotes, such as micro - printed text, watermarks, and security thread patterns, may be difficult to identify under normal light because their colors are similar to the main part of the banknote.

The magnifier can magnify these fine structures. After the invert processing, the originally light - colored watermark may become dark, forming a stronger contrast with the surrounding area, thus helping us observe.

It should be noted that the anti - counterfeiting designs of different currencies are different, and the effect of inversion is limited. In actual banknote checking, we still need to rely on formal tools.

Regarding the netizens' claim that "setting the filter to red can detect hidden cameras", this is because the infrared light emitted by the infrared fill lights of some hidden cameras is invisible to the human eye, but the camera sensor can detect it.

After setting the filter to red, the red filter may enhance the reflection effect of the infrared light, or make the lens show bright spots or red dots due to reflection under red light, thus helping us find hidden cameras.

However, this method depends on whether the camera uses infrared fill light and is also affected by ambient light, so it is not completely applicable.

All in all, although these methods are useful, they are just auxiliary means. You can just have fun with them, and professional matters should be left to professionals.

This article is from the WeChat official account "Technology Daily Push" (ID: apptoday), author: Huang Wanyi. It is published by 36Kr with authorization.