I've read your note a couple of times and reviewed the images several
times and I still don't see what you seem to see. To me all the test
images show as equally sharp across the depth of the test area. I just
can't tell a difference. But your comments on background details caused
me to look where I hadn't before. Recall that the original impetus for
this test was that the ZD Zoom supposedly showed more in-focus
background detail and thus "greater" DoF. OK, look at the brick wall in
the background. The brick wall is decidedly less sharp than the OM Z
even though it's operating at f/3.2 instead of f/2.8. That may be edge
of field resolution problems but the same would have been the case in
the original field/tree photo.
Anybody care to join in? Is it Moose's eagle eye that sees a difference
I don't? I've even tried blowing it up a bit beyond what is supposed to
be 1:1. I still can't see anything significant. This is the image
<http://zone-10.com/cmsm/index.php?option=com_content&task=view&id=528&Itemid=1>
Chuck Norcutt
Moose wrote:
> On 8/14/2010 3:10 PM, Chuck Norcutt wrote:
>> Hmmm. After reading your intro here I thought you were declaring
>> victory. But I sure don't see any difference between 5.8 and 6.4
>> meters. But that was tougher than really required I think.
>
> The Eagle Eye calls this one in favor of ... The Silver Snouted One.
>
>> Moving the goal post a full meter between the OM 24/2.8 at 5 meters
>> and the OM Zoom at 24/3.2(>) at 6 meters will move the depth of
>> field 5 meters further out.
>
> Much as I appreciate Chuck's thoughtful and informative contribution
> in the area of DOF, which I would never go the the trouble of doing
> for myself, the basis of the scientific method is empirical testing.
> To my eye, the circled points are subtly, but clearly, sharper than
> the same spots in adjacent strips.
>
> I also note that both foreground and background details show an
> orderly movement toward a more distant focus point.
>
> I appears that AG slightly missed focus on the middle 24/2.8 shot,
> compared to the others, but that it is still between the others.
>
> Should he post little, vertical resolution targets at each distance
> and double the distances , as you suggest, I'm convinced the proof of
> ability to focus accurately would be dramatic.
>
>> ... I think my hypothesis is still holding but I suspect you're not
>> going to try the extra 1/2 meter to disprove it. Just send me your
>> camera and lenses and I'll do it. :-)
>
> I disagree. Carefully thought out and calculated as your projections
> may be, I conclude that your hypothesis doesn't stand up to empirical
> test. Certainly it must be correct at some point as the test points
> get closer together, but at half the distances you proposed, it fails
> to my eye.
>
> Moose In Focus
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