This is a guide on how to lock down the iPhone 7 or iPhone 7 Plus OIS system and eliminate almost all internal sensor shake. There is no way to lock the camera lens through the software because this is a mechanical floating sensor. PLEASE NOTE: in the video examples we are inducing some chatter into the handle of the gimbal to exaggerate the movement in the sensor.
Apple's Optical Image Stabilization (OIS) system is comprised of a floating camera sensor between 4 magnets inside the lens housing. This is great for handheld iPhone video and can significantly help to stabilize the video from low frequency movements in the phone body but it was not designed to compensate for high frequency movements or vibrations which are commonly found when mounting your smartphone to a hard mount or even to a 3 axis gimbal such as the Shift or SP-PRO Gen2.
The fix for eliminating almost all OIS induced camera sensor shake is to use a 8mm x 2mm magnet on the front side of the phone placed directly behind your iPhone's camera. This magnet is stronger then the 4 internal magnets and will force the sensor inside the housing to remain in a locked stationary position which will eliminate the sensor from shaking erratically inside the housing when the phone is subjected to high frequency vibrations.
This fix is not 100% but it does significantly improve video quality when using your iPhone for video. Please note that using this fix is AT YOUR OWN RISK. The magnets used in this example should not damage the phone at all (we've tested this for quite some time with no issues what so ever) but we just need to say it so you understand that this is not an Apple approved technique.
***Please note: DO THIS AT YOUR OWN RISK***
We have done this for several months with no adverse effects to our phones, electronics, compass or OIS system. The magnet used in this video is a relatively small 8mm x 2mm neodymium magnet which you can buy on Amazon. If you were to permanently installed the magnet on your phone then there is a small chance that the magnetic properties of your OIS camera system would change and some additional metals in the phone may over a long period of time become slightly magnetize which is why we removed the magnet after shooting video.
It is worth mentioning however that the magnet used in this example is far SMALLER and LESS powerful then the commonly used magnets found on magnetic dash mounts from popular brands such as Scosche - these are also powerful enough to carry the weight of your entire phone. In our humble opinion, if a magnetic dash mount has no adverse effects on your smartphone over a long period of time while commuting in your car, then this small 8mm diameter magnet with a fraction of the magnetic strength is not going to have an adverse effect on the OIS system.