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Does increasing the depth of field increase the focus of...


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#1 Daniel Smith

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Posted 09 May 2007 - 06:55 PM

Hi.

I was taking a close up shot earlier (Picture) And the problem I had was that I was using a cheap nasty lens, and the front object did not focus fully.

Will increasing the depth of field bring objects behind the minimum focus point, into focus?

Thanks.
Dan.
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#2 Nick Mulder

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Posted 09 May 2007 - 07:20 PM

yes - but not to the same extent as objects in front of the plane
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#3 chuck colburn

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Posted 09 May 2007 - 07:38 PM

yes - but not to the same extent as objects in front of the plane


Hi Nick,

I always got that confused and thought it was the other way around. That is, that you got slightly more reach past the plane of best focus. Mayby I'll finally remember it this time. lol

Chuck
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#4 Nick Mulder

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Posted 09 May 2007 - 07:50 PM

I think we are on the same track in terms of the reality of the physical situation but have confused the terms 'front and past' with each other - I am the one probably getting it wrong..

I often refer to 'bring forward' instead of 'put back' in terms of time - I suspect something in my brain is wired backwards...

I remember reading somewhere about how researchers attempting to teach chimps (or gorillas ?) sign language got into trouble with concepts similar to this - they hypothesized that the animals concept of moving through time was that the animal walked backwards... i.e. they could see their past and were walking backwards into the unknown future...

Made a heap more sense to me than the typical 'walk forwards into the future' human concept for our movement through time and space...
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#5 chuck colburn

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Posted 09 May 2007 - 08:55 PM

I think we are on the same track in terms of the reality of the physical situation but have confused the terms 'front and past' with each other - I am the one probably getting it wrong..

I often refer to 'bring forward' instead of 'put back' in terms of time - I suspect something in my brain is wired backwards...

I remember reading somewhere about how researchers attempting to teach chimps (or gorillas ?) sign language got into trouble with concepts similar to this - they hypothesized that the animals concept of moving through time was that the animal walked backwards... i.e. they could see their past and were walking backwards into the unknown future...

Made a heap more sense to me than the typical 'walk forwards into the future' human concept for our movement through time and space...


LOL

Mayby it's caused your upside down in NZ!
Speaking of apes... I read that if you put a baby chimp and a baby human on a table surounded by clear glass at the same level as the table a chimp will not crawl out over the glass area but a baby child will. I'm putting my money on the chimp.

Chuck
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#6 Chris Keth

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Posted 09 May 2007 - 09:12 PM

Hi.

I was taking a close up shot earlier (Picture) And the problem I had was that I was using a cheap nasty lens, and the front object did not focus fully.

Will increasing the depth of field bring objects behind the minimum focus point, into focus?

Thanks.
Dan.


Yes it will. The minimum focus distance is not going to just cut off the depth of field or anything.

Depth of field will work like this:

Lets say there is a person standing 50 feet away facing the camera. You set focus right on their eyes. About 2/3 of the volume of the depth of field (which will be considerable at that distance, unless it is a very long lens) will be behind the person's eyes. About 1/3 will be in front of the person's eyes. As the person moves closer to the camera, the depth of field split gets closer and closer to 50-50-- that is, half of the depth of field in front of the person, half behind. The 2/3-1/3 split and the 1/2-1/2 split are never actually reached. It's one of those approach to infinity things from calculus.
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#7 Daniel Smith

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Posted 11 May 2007 - 07:38 PM

Ok thanks.
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#8 Chris Keth

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Posted 11 May 2007 - 07:49 PM

Ok thanks.


No prob. I'm what happens when a third-gen physics major decides to go into film ;)
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