title: Capturing a photo from only one lens, in dual-camera phones?
body: <p>Dual-camera smartphones are <a href="https://www.quora.com/How-does-dual-cameras-work-in-Android-phones" rel="noreferrer">relatively new in the market</a>, but I was wondering if a camera app could explicitly choose to use only one lens, or to manually retrieve separate input from each lens.</p>
  
  <p>I couldn't find any Android API documentation that is specifically designed for dual-lens phones, so I guess this is a hardware/OS-level implementation that would be difficult to override or bypass.
  <a href="https://source.android.com/devices/camera/camera3" rel="noreferrer">Android's Camera HAL documentation page</a> doesn't mention dual-lens devices as well, but it does seem to strengthen that assumption. 
  I don't have much experience with iOS, but I guess it wouldn't be easier.</p>
  
  <p>So the question is - how, if at all, would such task be possible on either Android or iOS?</p>
  
  <p><strong><em>Edit:</em></strong> seems that in iOS it is possible, <a href="https://stackoverflow.com/q/39385103/997940">as explained here</a> (thanks to <a href="http://the4kman" rel="noreferrer">the4kman</a> for pointing this out in the comments). So I guess the question remains for Android only. </p>