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Infinity vs. Hyperfocal


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#1 Ashim

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Posted 17 November 2006 - 11:13 PM

This might seem a very basic question but Ive gotta ask nonetheless.

If I want everythin to be in apparent focus, should I set the lens to Infinity or Hyperfocal Distance?
Kindly lemme kno.

Thank You
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#2 Mike Panczenko

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Posted 18 November 2006 - 12:16 AM

This might seem a very basic question but Ive gotta ask nonetheless.

If I want everythin to be in apparent focus, should I set the lens to Infinity or Hyperfocal Distance?
Kindly lemme kno.

Thank You



The hyperfocal will give you more dof than infinity, because it is everything from half that distance extending to infinity, whereas setting to infinity will not reach as close in terms of dof. Depending on how close your subject is though, you may have to set to something other than the hyperfocal to get closer objects into focus.
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#3 Ashim

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Posted 18 November 2006 - 12:35 AM

Actually the shot is this:

The subject will be very close to the camera, closer than the minimum focussing distance.
I want the subject and the background to be in focus.
We had thougt of a Split field dioptre but unfortunately cannot go with that due to budget constraints.

I dont think hyperfocal will help me with the subject this close to the lens.

So what could be the possible solution for executing this shot?

Thanks
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#4 Daniel Sheehy

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Posted 18 November 2006 - 02:13 AM

Shooting with a shorter lens and/or a higher f/stop will create a larger dof, bringing the hyperfocal distance closer to the lens. But even that may not be enough for the situation you've described.

Any chance of doing it as a composite shot?
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#5 Stephen Williams

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Posted 18 November 2006 - 04:13 AM

Shooting with a shorter lens and/or a higher f/stop will create a larger dof


Hi,

If the object in the forground remains the same size, changing the lens to a wider one won't help. Only stopping down the lens will increase the dof.

Stephen
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#6 Laurent Andrieux

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Posted 18 November 2006 - 06:44 AM

When you set the focus at the infinite the dof goes from the hyperfocal distance to the infinite (it's the hyperfocal distance's definition, BTW : the lower limit of dof when a lens is set at the infinite).

When you focus on the hyperfocal distance, the dof will go from half the hyperfocal distance to infinite.

It is the widest dof you can get, vs any other setting, at a given focal length and f-stop.

You can check on a dof calculator, that you can even find online, make a research here...

Once again, this was more a newbie question than a 35 mm related one... You should have posted in the dedicated section...
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#7 Jon Kukla

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Posted 18 November 2006 - 08:42 AM

Actually the shot is this:

The subject will be very close to the camera, closer than the minimum focussing distance.
I want the subject and the background to be in focus.
We had thougt of a Split field dioptre but unfortunately cannot go with that due to budget constraints.

I dont think hyperfocal will help me with the subject this close to the lens.

So what could be the possible solution for executing this shot?

Thanks


There is no way to get your subject in focus if it is closer than the minimum focus without using a diopter. Doing this will shift the focus closer and thus lose your background (if it isn't lost already). Your options (as mentioned before) are to either composite the scene, reframe it, chose a different lens, or stop down considerably. But if you don't have access to diopters, then you have to somehow get the subject within the minimum distance.
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#8 Daniel Sheehy

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Posted 18 November 2006 - 03:37 PM

Hi,

If the object in the forground remains the same size, changing the lens to a wider one won't help. Only stopping down the lens will increase the dof.

Stephen


Assuming that he is going to bring the camera in closer to maintain the subject size in the frame... you're absolutely correct.
If he switches to a wider lens & maintains the same subject-camera distance then he will get a larger apparent depth of field to play with... have to rethink the framing though.
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#9 Stephen Williams

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Posted 18 November 2006 - 04:15 PM

If he switches to a wider lens & maintains the same subject-camera distance then he will get a larger apparent depth of field to play with... have to rethink the framing though.


Hi Daniel,

Retaining the same lens and walking further backwards will also achieve a larger DOF!

DOF depends on image magnification on the film plane & F stop. The only way to increase DOF is to stop down or reduce the object size!

Stephen
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