Recently, I have been experiencing a major problem in focus for my images. Both my Nikon D750 and D300 were missing focus and even on subjects that were easy just days before. I chalked it up to hot weather or maybe it was just me being tired. Today, out at the wildlife reserve where I do my daily photo shoots of birds and wildlife, I happened to notice the the viewfinder image did not get sharp even on manual focus. Then almost out of desperation, I adjusted the diopter for the viewfinder. IT WORKED! The image was clear and I could achieve focus. So what happened?
A few days ago, I switched back to an older set of glasses which supposedly had the same prescription as my newer ones. I like the older ones for photography because of the large lenses as I get a wider view to scan for birds. I know that I had adjusted the diopter for the new lenses and assumed that nothing needed to be changed just be going back. Apparently, I was wrong. Both bodies needed the change and both immediately were far easier to focus.
This revelation points out the fact that while autofocus is fantastic, I do need verification that what I want focused on is in fact in focus before pressing the shutter button. I must have repeatedly overlooked this vital fact and assumed that the camera knew what I wanted. No more. Whew! Back to happy!