I was out taking pictures of our landscape project today, so while I was snapping pics rather that stacking bricks, I took some 50mm shots of one of our tiki torches with my little Canon.  It's approximate of course, but as close to 50 as I could get.

Oh ... ummm ... about f4.0, as I recall.

"If your pictures aren't good enough, you're not close enough."  ...  Robert Capa