Am 30 Aug 98 um 1:02 Uhr schrieb olympus-digest:
Date: Sun, 30 Aug 1998 01:02:14 -0700
From: owner-olympus-digest@xxxxxxxxxxxxxxx (olympus-digest)
To: olympus-digest@xxxxxxxxxxxxxxx
Subject: olympus-digest V2 #461
Reply-to: olympus@xxxxxxxxxxxxxxx
>Marco writes:
>The DOF remains the same.
>- ----------
>>If I add a 2x TC to get effectively a 500F4, and leave it set at F4
>>on the lens, do I still get y depth of field? Or do I get the depth
>>of field as if I am using the lens set at F8?
>You get the same DOF,
Yes
>but your subject is doubled.
Yes, but your circles of confusion are also doubled, that meams,
objects which were still sharp without teleconverter are now unsharp.
See my earlier posting on this topic.
>>Or is the depth of field at
>>(effectively) F8 on a 500mm lens the same as dof at F4 on a
>>250mm.
>Yes, that is why it is the same.
No, DOF is halved.
>The TC *enlarges* your image. That is all. The dof cannot vary. If
>you had a
Here is an example:
A 200 mm lens at F=4 focused at 30 m has a depth of field from 27.33
- 33.25 m. (5.92 m)
This lens with a teleconverter (which gives a 8.0/400 lens) has a
depth of field from 28.65 - 31.49 m. This is 2.84 m , about the half.
The numbers are from F.Pangerl "Die Welt des OM Systems".
It is confusing, I know!
Christoph
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