Which? tests show iPhone 4 proximity problemsiPhone 4 proximity sensor found 'less sensitive'

07 July 2010

Apple iPhone 4

The Apple iPhone 4 does suffer from a less sensitive proximity sensor than the iPhone 3GS, an independent lab test of the iPhone 4 has confirmed.

iPhone 4 users have been complaining that the proximity sensor on Apple’s new iPhone 4 is less sensitive than previous models – leading to the screen remaining active during calls when the iPhone 4 is held up to the face. The result, claim some users, is the accidental activation of on-screen buttons leading to calls being hung up, placed on speaker phone, new calls being made, or the switching on of Apple’s FaceTime video-conferencing feature.

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UK consumer champion Which? tested the iPhone 4’s proximity sensor in its labs against the iPhone 3GS. Initial findings show that the iPhone 4 has a significantly less sensitive proximity sensor compared to the iPhone 3GS – with a performance difference of nearly one third.

iPhone 4 proximity sensor

The Which? experts measured the distance the proximity sensor was triggered from a surface on both phone models – and found the proximity sensor on the iPhone 3GS blanked and deactivated the screen and on-screen buttons about 55mm from the target surface.

The iPhone 4 model was found to blank and deactivate the screen about 40mm from the target surface – a difference of nearly 30%.

The Which? labs test also found the iPhone 4 sensor is slower at deactivating the screen than the iPhone 3GS. It found the iPhone 4 took about a half-a-second longer to deactivate the screen when it reached the activation range of the test surface, compared to the iPhone 3GS.

Read the first look Which? iPhone 4 video review

iPhone 4 firmware fix?

Which? is recommending to Apple to release a firmware fix that addresses the proximity sensor issues, and is carrying out further research into the issue.

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