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Forums > Back > The (non)sense of hyperfocal distance
frank
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#25
09-07-2011, 09:28 AM
[quote name='Klaus' timestamp='1315385318' post='11371']

The Sigma 12-24mm II is an example for a lens where the field curvature does not overly change when stopping down. The depth-of-field simply "catches up" (=hides the field curvature) so from a real world perspective it is "reduced" although technically it is still there.



Remember that field curvature is just about focus. If you set the center focus to e.g. 2m the border focus could be at -say- 5m (or 1m) due to the curvature of the focus field. Imagine that the focus plane is not a wall but a sphere.

Stopping down increases the depth-of-field and it will increases at the whole "focus sphere" and at some stage you will simply have a sufficient depth-of-field in the border zone as well.



To explain my wording:

Focus - 2m center, 5m border: negative field curvature (the border focus is "pushed" away)

Focus - 2m center, 1m border: positive field curvature (the border focus is "pulled" towards you)

[/quote]





Thank you again, Klaus. I understand it better now.



Frank
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Messages In This Thread
The (non)sense of hyperfocal distance - by Rainer - 09-06-2011, 09:02 AM
The (non)sense of hyperfocal distance - by PuxaVida - 09-06-2011, 12:29 PM
The (non)sense of hyperfocal distance - by Klaus - 09-06-2011, 12:34 PM
The (non)sense of hyperfocal distance - by frank - 09-06-2011, 03:56 PM
The (non)sense of hyperfocal distance - by Klaus - 09-06-2011, 04:20 PM
The (non)sense of hyperfocal distance - by youpii - 09-06-2011, 07:42 PM
The (non)sense of hyperfocal distance - by Klaus - 09-06-2011, 08:07 PM
The (non)sense of hyperfocal distance - by Klaus - 09-07-2011, 04:52 AM
The (non)sense of hyperfocal distance - by frank - 09-07-2011, 06:11 AM
The (non)sense of hyperfocal distance - by frank - 09-07-2011, 06:17 AM
The (non)sense of hyperfocal distance - by PuxaVida - 09-07-2011, 06:33 AM
The (non)sense of hyperfocal distance - by frank - 09-07-2011, 07:00 AM
The (non)sense of hyperfocal distance - by Klaus - 09-07-2011, 07:44 AM
The (non)sense of hyperfocal distance - by Guest - 09-07-2011, 07:51 AM
The (non)sense of hyperfocal distance - by frank - 09-07-2011, 08:00 AM
The (non)sense of hyperfocal distance - by frank - 09-07-2011, 08:01 AM
The (non)sense of hyperfocal distance - by PuxaVida - 09-07-2011, 08:11 AM
The (non)sense of hyperfocal distance - by Dick England - 09-07-2011, 08:23 AM
The (non)sense of hyperfocal distance - by Klaus - 09-07-2011, 08:48 AM
The (non)sense of hyperfocal distance - by frank - 09-07-2011, 09:28 AM

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