I'm afraid I'm not yet convinced. There are two compounding factors not
controlled for.
The first is the performance of the lenses at f/4... an aperture much
more easily handled by the 4/3 lens which should be designed to shoot
high quality images at a couple of stops wider than the Zuiko 24/2.8.
The second is the focusing accuracy achievable at 5 meters. By your
calculations, DoF extends to 10.3 meters which implies using a CoC of
0.015mm. But that's at f/4. Presumably you were focusing at f/2.8 with
the Zuiko and probably about f/3.2 with the zoom (which has an aperture
range of 2.8-3.5). Since you're using a magnified image for focusing
I'll allow that the effective CoC is cut in half and tightens up to
0.0075mm. That would allow your actual focus at f/3.2 to be as far away
as 8.5 meters instead of 5 meters and still not detectable to the eye.
Then, when the CoC is relaxed back to 0.015mm and f/4 taking aperture
the far DoF can extend all the way to 70 meters.
I'm not saying that's what happened but I don't think you can say with a
very high degree of certainty that it didn't.
Chuck Norcutt
Ken Norton wrote:
> I just posted an article on www.zone-10.com that illustrates two
> identical photographs taken with two different lenses which shows how
> effective DoF can vary from one lens to another.
>
--
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