Mark wrote:
> I did not take any actual pictures to test the quality of this combo. I
> have tried using my ATX with teleconverters, and have not been happy with
> the results. I'll also break from the consensus here and say that I don't
> consider the 1.7 AF converter to be all that good. When I combine mine
> with a 50mm f1.4, point it at a bright shiny object in the sun, and
> de-focus I see all sorts of wild rainbow / prism patterns. This is
> consistent with different lenses.
Mark, this has nothing to do with the converter. It's simply the
nature of the focusing screen in newer AF cameras, where the whole
screen is of very small micro-prisms. After one aperture (e.g. 6.8 in
my SFXn's screen), some optical effects make this rainbow patterns
happen. When I wrote about it here, I was accused of smoking some dope
:) Especially at f/8, these rainbow hues are much apparent. Pentax
should have marketed it ;-)
It is also apparent in bokeh/defocused areas, there is visible
horizontal rainbow lines.
So I guess this is because of the camera, not converter.
Frantisek
BTW, how do you like the lens, mainly wide open, at long end? Compared
to a long prime?"Thanks.
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