Esteemed colleague of Dr. Focus says:
My take also. I don't understand the why and Shaw doesn't really say
other to comment on changing focal lengths. But I don't believe his
results are in error... nor do I think they are specific to the
particular pieces of equipment he used. He attributes these results to
the generic equipment arrangements.
Chuck Norcutt
Something is very askew here. My initial impression was that internal design
differences may save a modest
amount of light, say 10-20%. I really really like JS's first macro book
"Closeups in Nature" and he clearly takes careeful
measurement of working distances. I have trouble with the finding that the
micro Nikkor 200mm at
f4 is still F4 at 1/2X while straight extension loses 1 stop as predicted by
that N[eff] = N (1+M)---
Clearly violates the "No free lunch principle" though Moose has a slightly
different designation.
I did not remember the statement on pg 75 that the Canyon 200 macro lost only 1
stop at 1X????
Perhaps I should have purchased stock in that cold fusion start-up afterall.
I thought this Jabberwok issue was slain, though it appears to be just wounded.
i will rejoice,
when it is clarified as it has bothered me for a looong time.
“And hast thou slain the Jabberwock?
Come to my arms, my beamish boy!
O frabjous day! Callooh! Callay!”
He chortled in his joy.
A puzzled frumious Mike
Moose wrote:
> On 4/22/2010 3:41 PM, usher99@xxxxxxx wrote:
>
>> and even made it into print (pg 74 JS first macro book)
>
> I'm not ready to dismiss Shaw's results without further consideration,as
> they appear at first glance to be the result of empirical observation
> and he seems to be fairly careful as experimenter and observer.
--
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