Circle of Confusion

By: pbcmedia

Nov 25 2008

Tags: , , , , ,

Category: Creativity, Life, Personal, Photography


Focal Length:100mm
Shutter:1/0 sec
Camera:Canon EOS 5D

Oh, this is a beauty and I don’t mean pretty.

Think Jackie Gleason (if you go back that far) when he was suggesting to Alice that she might want to take a trip to the moon.  I mean beauty “pain in the rear” right at the moment.

This week’s SPACC theme was “depth”.  My series for this week, independent of SPACC, was “Behind the Wheel”.  So I,  of course,  went in search of photos about depth behind the wheel.

Each day I took more photos.  Each day I deleted more photos.  Nope.  Nothing.  Nada.

Then, I did what I should have done in the beginning: googled “depth”.  Thinking, well, I’ll find a poem or something.  But, curiously, this search led me to what a photographer really should have thought of right off the bat.  Depth of field.  And, a new term to me, but not new to the discussion of depth of field apparently, the “circle of confusion”.

I’m no stranger to confusion (particularly in the past two months) and I love circles so what’s not to love?

Besides, although I didn’t know the term, I usually am wrestling with this circle of confusion behind the wheel, perhaps, more than most photographers.  Let me explain.  Apart from this week’s series, where if I have anything in focus at 1/10th of a second in a moving vehicle, it’s a miracle,  I nearly always take photos of intersections at twilight or dawn regardless of what week it is.  See these past posts:

1 November

2 October




Often I am stopped at the light with my telephoto macro on manual, deliberately wanting the color fields and shapes that affords but also wanting something in focus.  That is why rain is my preferred weather condition at the stoplight.  I can focus on the raindrops on the windshield while the lights from the cars and traffic lights are enlarged and merge into fanciful shapes and patterns.

Well, this morning it rained.  In fact, it was pouring when I woke up before dawn.  O, Depth!  O, Circle of Confusion! I’ve got you this morning!  I’m gonna circle your confusion like the space shuttle.  I get my coffee and off I go draped in my Maine rubber slicker that makes up in waterproofing what it lost in attractiveness.

I parked in the CVS drugstore parking lot which faces an intersection with stoplights.  The store was closed but the lights were on.  If you look at the raindrops that are in focus (there aren’t that many but they are there and jpeg doesn’t help) you can see the bank of lights of the store and the trees in their reflection.  This was, in fact, the only shot of many where I had some of these drops in precise focus.   It is a balancing act in the macro mode with a curved windshield, low ISO (I like to blow these things up big big), wide aperture, and slow shutter speed.

At any rate,  this circle of confusion is used “to define how much a point needs to be blurred to be considered “unsharp”” and when it is defined, it is then considered to be outside the depth of field and no longer “acceptably sharp”.

So, as you can see, I’ve got me some circles in this here photograph, inside and out of that circle of confusion. Whether this makes a pleasing photograph is not the point this week, but it sure as hell demonstrates this: that depth of field and circles of confusion are a dynamic proposition when the photographer is slightly crazy.

I’ll leave you to become cross-eyed, as I have become, trying to pick out that moment when everything in front of or in back of one raindrop begins to lose sharpness.

Are we having fun, yet?

To the moon, Pat.  To the moon.


SPACC contributors. Deadline is Wednesday, November 26.







©Pat Coakley 2008


11 comments on “Circle of Confusion”

  1. You know how I love water. These droplets look almost like the mercury droplets out of an old fashioned thermometer. As kids when one broke open we’d play with the little steel colored balls of mercury. I don’t think I’ve mastered depth of field just yet, but you sure have…bravo :0)

  2. Very nice. Almost looks like one of those strobe shots that stops motion, that has captured falling rain.

  3. In German we call it “Diffusionskreis” which is a lot more technical, longer and less poetic than the “circle of confusion”. When I read the English word for the first time in my life, I could not believe what strange paths language can take, wonderful! circle of confusion…especially remembering my 1st year class film school, black and white lesson, colour was to follow in semester 3 only…you should have seen all this circled confused little faces of ours…
    The most poetic description of what technically happens, I found to be the one of two lines or dots, being close enough together to appear as one and merge for the human eye. did you know different lens manufacturers operate with a different number for the circle of confusion? and how much fun would it be to shoot once something for a birds or dragonflies eye…I wonder how big their confusion would be…

  4. Sweetiegirlz: Now, that you have your nice camera, you’ll have reason and capability to find out about “depth of field”. Am so glad you are going to do the weekly photo challenge!!

    Razz: god forbid I should have a flash or a tripod or anything that might help me in these situations! I’d like to have some nice tripod mounted on the dash!

    Sanne, This is so interesting to me. I have never heard of this term so it makes me smile to think about all your circled confused little faces in film school! No, I didn’t know different lens manufacturers operate with a different number for the circle of confusion! Now, that is…well…that is confusing! I’ll leave it to you to give us the dragonfly’s world view, though. That really would be wonderful.

  5. The mechanics of photography are better understood when I read the description of your process. And the start of your day in the dark, cold, rainy early morn. The ” focus ” of your determination to bring your experience and skill to higher levels.
    All so revealing Pat.

    Sweetiegirlzs’ comment is the first thing I thought of as I looked at it having the same experience once. Chasing elusive silver balls.

  6. I agree with sweetiegirlz – the first thing I thought of was mercury on a mirror. The liquid silver quality of the drops is very cool. They look to be on the inside of the glass…strange.

    Nice shot overall. Matte and frame a few – I bet they would sell.

  7. I wasn’t going to read the other comments but then I see Michael’s above about mercury & let out a big sigh. That’s what I thought! This is absolutely gorgeous. It is my new favorite of your behind the wheel series. When I look closely i can see the store & the tree. In some drops, they are very clear while others are more blurred even thought the drops look crisp. I am now going to have to google “circle of confusion.” That is a new one for me. Oh, also, I am proud to say that I got a traffic light to blur. It’s not good. I’m still working on it.

  8. Bonnie, I seem to be the only one who has never played with mercury as a child!!! Isn’t that dangerous? Anyway, determination is really just an investment in the whole creative process. (In these times, an investment that doesn’t lose money). It pays off dividends in sanity and balance. Without it, well, I don’t want to think about that.
    Mt. Brooks, They do appear to be on the inside of the glass, I agree. Maybe because there was some back light from the store? Perhaps, because there was illumination from both streets, as well. I can guarantee you this, I couldn’t duplicate it. I know this for sure. Thanks.
    Conni, Seriously, have you ALL played with mercury?? Some of the drops were not stationary as in dripping down the windshield. I think that accounts for some of the drops that appear in focus but are blurred. It was a downpour kind of rain so there was movement all the over the place. Excellent that you got that traffic light to blur! I know that feeling.

  9. Love the circles (of confusion), love the blurriness behind, love the feeling of wanting so much to see what’s beyond the frame… most of all, I’d like you now to do a MOON photo for us. It’s round (at times). I’m sure you can do it and make us look at the moon in a whole new way. Go for it, Pat! To the MOON and back, and then you can tell us the story of your lunar journey.

  10. This would absolutely sell! It’s beautiful Pat. I especially love the reflections of the scene in each droplet. Very Nice.

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