Dear Wise Ones,
Slightly embarrassing question: I see the "focus distance" picker and have clicked on the nearest object. Depth of Field is "on" in render settings and I set the Blue Strength to 50% (with all four subsequent boxes checked) and yet when I render, I see no depth of field.
I'm sure this is something blisteringly simple, but I've been working on a project all day and my brain is a tad fried and the deadline is looming....
Thank you for your help.