I have simulated zoom out functionality in different way, What I have done is I reset to identity(bringing back to original size) and zooming in again to what position I want like this..
if (cameraTransformX == 2.0) {
preview_picker.cameraViewTransform = CGAffineTransformIdentity;
cameraTransformX -= 1.0;
} else if (cameraTransformX == 3.0) {
preview_picker.cameraViewTransform = CGAffineTransformIdentity;
preview_picker.cameraViewTransform = CGAffineTransformScale(preview_picker.cameraViewTransform, 1.0, 1.2499);
cameraTransformX -= 1.0;
} else if (cameraTransformX == 4.0) {
preview_picker.cameraViewTransform = CGAffineTransformIdentity;
preview_picker.cameraViewTransform = CGAffineTransformScale(preview_picker.cameraViewTransform, 1.0, 1.2499);
preview_picker.cameraViewTransform = CGAffineTransformScale(preview_picker.cameraViewTransform, 1.0, 1.2499);
cameraTransformX -= 1.0;
}
I know its not a proper way to go back to previous transform, but it will do the tricks. :)