Exposure Triangle

[theantiquetiger]

I posted this image on another forum and said I bumped the ISO to get the faster speed (shot at 2.8 in AV).

Someone replied that if I had lowered the ISO, the people in the BG (behind the net) would have been OOF.

I replied and said ISO has nothing to do with DOF (directly), especially when shooting at max f-stop and AV mode. It would only slow the speed down, causing movement blur.

Someone else said to learn the Exposure Triangle. (I am not sure if that was directed at me or the other poster)

Am I correct or am I missing something?


courtney2 by Theantiquetiger, on Flickr

[Runmonty]

As far as I am concerned you are correct - aperture is key to DOF.


Although not a direct answer to your question - Bear in mind though that hyper-focal distance will vary depending on the focal length of the lens and the distance to the subject as well.

[Marko]

Someone replied that if I had lowered the ISO, the people in the BG (behind the net) would have been OOF.

Only if lowering the ISO also allows me to grow magic hair.

[theantiquetiger]

The guy that posted "learn the exposure triangle" has since replied with this (and still doesn't make sense to me)...

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"It was directed to you.

First, you shot the picture in question at 5.6, not 2.8, so User3977 suggested to drop both the iso down and the aperture down to 2.8 from 5.6 to further blur the background to make the subject pop and to keep it less distracting.

Second, correct, ISO has no affect on DOF, but I think you missed the point: If you added two stops more of light you could have lowered the ISO to ~100 without having to sacrifice any shutter speed.

Or alternatively you could have kept the ISO at 500 and just increased the shutter speed, since the 60D goes to 1/8000, to keep the same exposure."

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Now I am even more confused. How would closing the aperture and lowering the ISO make the BG more out of focus? To me, it would make it more clear (broader DOF), and just under exposed and movement blur.

[theantiquetiger]

Never mind, disregard this thread. I was thinking the entire time I was at 2.8, but I was at 5.6 (the one of Maddy in midair is at 2.8). The guy was suggesting lowering the ISO and f-stop to blur the BG behind the net.