Which iPhone 4 Cases Won’t Fit the 4S?

Despite looking virtually identical, iPhone 4S owners are discovering that some cases made for the iPhone 4 don’t necessarily fit an iPhone 4S.

The biggest design change is that the ambient light sensor on the iPhone 4S was shifted a few millimeters to the left, CNET reports.

this doesn’t affect standard iPhone cases like those from Speck and Casemate, but it certainly matters to rugged cases that come with a partial screen protector. With the light sensor hiding behind the screen, the iPhone 4S thinks its always in a dark area and automatically dims the screen to conserve the battery. White or pink LifeProof iPhone cases are fine because enough light passes through the cases so as not to impact the sensor.

OtterBox came clean about its iPhone 4 and iPhone 4S case incompatibility. instead, it recommended customers buy one of its Defender or Impact Series cases designed for iPhone 4S, which have a larger opening around the camera and proximity sensor to accommodate both versions.

other rugged cases like the Griffin Survivor case for the iPhone 4 and Magpul Field Case for the iPhone 4 both work because of a larger cutout up front, according to readers.

Gizmodo Australia also noted that the iPhone 4S was modeled after a Verizon iPhone 4. If you’ll remember, the Verizon iPhone 4 moved the mute switch on the left side about a millimeter from the AT&T iPhone 4. Gizmodo’s writer rated iPhone 4 cases that worked on both the iPhone 4 and the iPhone 4S. According to Gizmodo, the most compatible iPhone 4/4S cases are: Griffin FlexGrip, Griffin Elan Form Graphite, Padacs Breeze, and Griffin Elan Form.

Last week iPhone 4S owners also reported seeing a yellowish tint in their screens, dubbed “yellowgate.”

For more, see the iPhone 4S case slideshow below, as well as Can the iPhone 4S Replace Your Digital Camera?

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