Saturday, January 10, 2009

January 10th - Bokeh Tapes

Looking at Eric's photo today, I noticed something about the focus and almost fired off an email to him to ask why, and then thought "No - I'll do an experiment to answer my question, and that will be my Bokeh photo for today". So here it is, but I think I need a different lens to really do this experiment. I could only stop down to 4.2 - my lens doesn't go very wide open. So someday when I have a lens that does, I'm gonna redo this experiment. What I expected was to see the 12" mark on the center tape measure be in sharp focus and then somewhere around the 10-1/2 and 11-1/2" marks on the outside tapes be in focus because their angular distance from the lens rather than their straight [linear?] distance from the edge of the table. But at f/4.2 it doesn't really look that way does it? Anyway, here's today's photo 1/20 sec. f/4.2 iso 200.


  1. Oooh, what a neat experiment! I'm gonna hafta try that too. COuld you send me a box of tape measures?

    Say, too bad this old Nikon 55 1.2 doesn't fit your D50, eh?

    Hey, I wonder if the focus behavior is because the 'film' plane is also flat?

  2. Great experiment and the contrast is fantastic. Hmmm I would think the anything 5.6 or greater should give you a pretty good DOF. Nicely done...and how weird would that have been if you posted horizontal instead? I would have been scratching my head over that one.

  3. I don't see a new header?
    did you forget to save?