I expected this could be your answer :-) I just too lazy to shot another F11
or F16 shot. In that case you will not detect the 28mm shot's backgroud is
out of focus and the 300mm shot will just look the same (serious out of
focus).
Even I took another F11 shot you may say my 21MP sensor is too low in
resolution. I need a 400MP sensor since the COC used in the calculation
should be 0.003mm not 0.03mm. A higher pixel sensor is required :-)
BTW, I just put 0.003mm as COC to the calculation, the DOF of 28mm lens is
still much bigger than a 280mm lens with 0.03mm COC. Or the calculator
itself is wrong?
I used the following data:
F11, object distance 10ft, COC 0.003mm, the DOF of 28mm lens is 2.66ft
F11, object distance 10ft, COC 0.03mm, the DOF of 280mm lens is 0.24ft
http://www.dofmaster.com/dofjs.html
C.H.Ling
----- Original Message -----
From: "Ken Norton"
>
> We must not confuse "bokeh" with DoF. The 300mm image is exhibiting the
> bokeh characteristics of a specific lens design (I'm assuming Zuiko
> 300/4.5
> as it has this distinct look), but the cropped image shows the bokeh
> characteristics of a modern wide-zoom. The backgrounds in each shot are
> out-of-focus, so there is no comparing DoF, just bokeh.
>
> Ctein alludes to something in one of his last posts in that topic when he
> states:
>
> "Something I hadn't mentioned, and possibly should have sooner, is that
> trying to nuance this too far is pointless, because real-world lenses
> NEVER
> have the same DoF that the equations predict. The precise shape of the
> light
> 'cone' near the point of focus has a big effect on where the diameter of
> the
> envelope hits the CoC limit, and the shape of that envelope is very
> sensitive to lens designs and residual aberrations. There have even been
> lenses with a floating element that tweaked the mix of aberrations so as
> to
> let the photographer alter the balance between near and far DoFs!"
>
> This is something that I've been harping about in the diffraction-limits
> and
> DoF discussions for years. Many modern telecentric lens designs with
> multiple asperical-shaped lenses have the ability to direct the "cone" in
> such a way that you get very little spread and in fact will actually
> invert
> the cone for out-of-focus light paths forming ring-shaped bokeh artifacts.
> I have noticed over and over again how some modern lenses do not have a
> "plane of in-focus" but more of a "zone of in-focus"
>
> AG
> --
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