MKMapView custom pins change when I zoom in and out - iphone

Question

I'm making an app that uses MKMapView. I add custom pins (with image). And now when I zoom in and then zoom out, pins change back to default (red color).
Here is my code:
- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation
{
static NSString* SFAnnotationIdentifier = #"Kamera";
MKPinAnnotationView* pinView =
(MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:SFAnnotationIdentifier];
if (!pinView)
{
MKAnnotationView *annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation
reuseIdentifier:SFAnnotationIdentifier];
annotationView.canShowCallout = NO;
UIImage *flagImage = [UIImage imageNamed:#"pinModer.png"];
CGRect resizeRect;
resizeRect.size = flagImage.size;
resizeRect.size = CGSizeMake(40, 60);
resizeRect.origin = (CGPoint){0.0f, 0.0f};
UIGraphicsBeginImageContext(resizeRect.size);
[flagImage drawInRect:resizeRect];
UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
annotationView.image = resizedImage;
annotationView.opaque = NO;
UIImageView *sfIconView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"kameraNaprejModra.png"]];
annotationView.leftCalloutAccessoryView = sfIconView;
return annotationView;
}
return nil;
}

Answer 1

The code is not handling the case where the dequeue returns a non-nil pinView (meaning it is re-using a previous annotation view).
If pinView is not nil, the method ends up at the last line which returns nil for the annotation view.
When you return nil, the map view draws the default annotation view which is a red pin.
Adjust the code like this:
if (!pinView)
{
//no changes to code inside this if
//...
return annotationView;
}
//add an else part and return pinView instead of nil...
else
{
pinView.annotation = annotation;
}
return pinView;