Steve, in one of your videos you spoke of a particular piece of lens testing gear that you use for determining and fixing back or front focusing on a lens. It seems like I could use the product. It had a target and also a rail to determine where the lens was actually focusing. I think it might help me stop blaming the equipment for my soft shots. Currently I just use a flat target on a wall. Could you either refer me to the video or perhaps discuss it a little more here. I’m guessing that each lens would have a different correction for each camera it’s used on. Where can it be purchased and is it difficult to use? And finally, do you recommend it or is field testing enough. Thanks.