Apple support forums quote few users apparently having issues with iPhone 6 Plus OIS or AF actuator. The image appears blurry and wobbly and phone is audibly vibrating. It's not known how widespread is this defect, but many web sites talk about that: Phonearena, Daily Mail, BGR, and more. Only iOS 8.1 devices reported to be affected so far. A Youtube video shows the defect:
Other video demos are here, here, and here.
Awesome visual effect. Looks like classic feedback instability. I suppose the engineers at Apple are quite busy trying to figure out how to fix this without a phone recall. Hopefully it can be fixed via software.
ReplyDeleteIt does look like the OIS control loop is unstable (at some particular shake frequency? That's the sort of think QA may just miss if they don't get the conditions just right but I didn't the devs simulate the loop before coding to check for stability? Perhaps they did and the model they isn't quite faithful to the hardware).
DeleteAs this problem appeared with iOS 8.1 on iPhone 6 that were OK under iOS 8.0 I presume a firmware updated with a more stable OIS feedback loop will fix it without a hardware recall.
couldn't the wobbling be caused by a "beat frequency" between the rolling shutter frame rate and OIS movement?
DeleteBut what feedback? It is more a feedforward system. Gyro measures, current is applied.
DeleteAny feedback is from a positional sensor to the current. The gyro will not be involved. I think?
Could it be a sort of parasitic acoustic feedback where vibrations caused by OIS motor affect the gyro, and then feed back to the motor? The affected iPhones are reported to be audibly vibrating, so if gyro is close and not acoustically isolated, it could form a loop.
DeleteThe problem seems is not wide spread. Thus it is likely due to some bad components.
DeleteOn the modules I have seen, the gyro is on the camera module itself. Nokia used that gyro also for the application processor, but the Nexus 5 has a separate gyro for that on the main board. The OIS gyro is faster I think, and 2 axis, not 3 axis.
DeleteHaving them integrated makes for easier testing. But there could be an influence depending on the way the module is mounted.
Prolonged use of VCM movement as shown in the video will create thermal issues and cause irreversible damages.
ReplyDeleteApple is no longer Apple now. How can they skip such kind of phenomena?
ReplyDeleteDid someone leave the "rippling water" feature enabled? Surely a fantastic selling point of the camera.. ;-)
ReplyDeleteDoes any know which OIS Apple is using? TDK?
ReplyDelete