Finnish tech company OptoFidelity uses robotic technology to test the responses of smartphone touch screens. Courtesy OptoFidelity

EVER wondered why you can never type a certain word correctly or always mange to hit the wrong button on your iPhone?

Well, so have a bunch of tech gurus who set about proving it isn't always human error when things go wrong typing on your Apple device.

Finnish tech company OptoFidelity wanted to find out the difference for phone users when it came to performing common tasks including web browsing and opening a camera application.

To get their answer they pitted the performance of the Apple 5S and the cheaper 5C model against an older Samsung Galaxy S3.

The company then conducted a number of automated tests, one of which measured the accuracy of the touch panel and found what Apple users have probably long suspected - iPhones might be fast but they lag behind in touch accuracy.

Using OptoFidelity touch panel measurement devices, it compared the coordinates of touches by a robot with an artificial finger to coordinates from a touch device.

Still unclear what that means?

The picture below may help explain things better.

A pass or fail score was recorded when the actual touch position registered greater than 1mm off from the reported coordinates from the artificial finger.

Passes were marked with green dots while fails were noted in red.

This means that for an onscreen keyboard, with a QWERTYUIOP row, neither the iPhone 5S or the 5C would be able to properly detect whether you typed Q, I, O, and P if you're touching them close to the edge of each actual key.

The picture also shows that the Galaxy 3S only loses accuracy towards the very edge of the key, while the iPhones are substantially more inaccurate.

This may explain why iPhone users get a lot of typing errors on both devices and not because their screens are smaller than the Samsung rival.

For more information on the test go to the OptoFidelity report.

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