I have just taken delivery of a new Nikon 24-70mm f2.8E ED VR lens. Having read some reviews that have discovered quality assurance issues, especially over AF accuracy and performance, with this lens can members recommend some simple tests to ensure I have a correctly functioning lens. It will be working with a D810. I will start taking pictures of a brick wall at various focal lengths, with and without VR, and at various focal points. Is this a correct approach and am I missing anything obvious? I do not have access to any complicated charts or graphics. Suggestions would need to be practical for an amateur! My thanks, as ever, in advance for any wise advice.