I wanted to take a photo of my brother with traffic trails behind him. Now even when I was using a tripod, and A/F was correct, I still couldn't get the subject to be sharp, despite using a self timer of 5 seconds (didn't have a shutter release).
Why is the picture blurry? What can I do to capture the effect of a clear subject with no motion blur, with a motion-blurred background?
I am using a Nikon D3300, at 3 sec exposure, f/4.5, ISO 100.