Detect When AVFoundation Camera Finishes Focusing

Question

I currently am using AVFoundation to run my camera, but I want to be able to detect when the camera finishes focusing. Is there any way to do this?

Thanks so much!!

Answer 1

According to doc

You can use the adjustingFocus property to determine whether a device is currently focusing. You can observe the property using key-value observing to be notified when a device starts and stops focusing.

If you change the focus mode settings, you can return them to the default configuration as follows:

Answer 2

In the initialisation:

[[[captureManager videoInput] device] addObserver:self forKeyPath:@"adjustingFocus" options:NSKeyValueObservingOptionNew context:nil];

and then:

bool focusing = false;  
bool finishedFocus = false;
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    //[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
    if( [keyPath isEqualToString:@"adjustingFocus"] ){
        BOOL adjustingFocus = [ [change objectForKey:NSKeyValueChangeNewKey] isEqualToNumber:[NSNumber numberWithInt:1] ];

        if (adjustingFocus) {
             focusing=true;
        }
        else {
           if (focusing) {
                focusing = false;
                finishedFocus = true;
           }
        }
    }
}