Before I go in to detail, I am fully aware duplicate image finding software exists; I am looking for something specific.
Rather than find all duplicates images (I already know I have duplicate images all over my filing system - this is intentional), I wish to select a particular image and then...
I registered to specifcally answer this question because I had a similar problem.
In addition to the points above, please refer to the image below and read on:
Have you accidentally moved this switch to 'L'? If so, it will lock whatever autofocus settings you had at the time of setting it...