Map camera position changes sharply without animation

I use google Maps SDK for iOS. I have markers on my map and want to set proper zoom so that markers are separate and also markers should be visible on screen all at once. I am able to do it.I have done using logic that if all markers are visible then zoom in. But the problem is that map camera is changing sharply. I tried a lot to animate this zoom but I failed to do to. I tried animateToCameraPosition, animateToZoom and UIView animation method.

- (BOOL)allCoordinatesVisibleWithLatitudes:(NSArray *)arrayOfLatitudes Longitudes:(NSArray *)arrayOfLongitudes
    {
    CLLocationCoordinate2D coordinate;
    for(int i=0;i<arrayOfLatitudes.count;i++)
    {
        coordinate = CLLocationCoordinate2DMake([[arrayOfLatitudes objectAtIndex:i] floatValue], [[arrayOfLongitudes objectAtIndex:i] floatValue]);
        if(![self.mapView.projection containsCoordinate:coordinate])
        {
            return NO;
        }
    }
    return YES;
}


- (void)setZoomToHaveProperView
{
    NSMutableArray * arrayOfLatitudes = [[NSMutableArray alloc] init];
    NSMutableArray * arrayOfLongitudes = [[NSMutableArray alloc] init];
    RS_SingleMatch * singleMatch = [[RS_SingleMatch alloc] init];
    float zoom = 0.0;

    // You may ignore this first for loop. it just takes coordinate of all markers in     arrays.

    for(int i=0;i<=self.userMatches.arrayOfMatches.count;i++)
    {
        if(i==self.userMatches.arrayOfMatches.count)
        {
            RS_Trip * userTrip = [[RS_Trip alloc] init];
            [arrayOfLatitudes addObject:[NSNumber numberWithFloat:userTrip.fromLat]];
            [arrayOfLongitudes addObject:[NSNumber numberWithFloat:userTrip.fromLon]];
            if(self.segmentedControl.selectedSegmentIndex == 1)
            {
                [arrayOfLatitudes addObject:[NSNumber numberWithFloat:userTrip.toLat]];
                [arrayOfLongitudes addObject:[NSNumber numberWithFloat:userTrip.toLon]];
            }
        }
        else
        {