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12-22-2007, 06:33 AM   #16
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QuoteOriginally posted by Canada_Rockies Quote
The aberrations of the prime lens will be increased in size by the multiplication factor of the TC. If your purple fringe is 10 pixels on a lens, with a 1.4x TC it will increase to 14 pixels, 20 pixels with the 2x.

In simplistic terms, whatever comes out of the back end of the lens will be proportionately larger. In addition, if the converter adds some fringing, it will be worse.

I am not sure that I will be using my A 1.4x-S any more, now that my 400 is equivalent to 600, which is what I used the 1.4x for.
I am not so sure about this. It assumes that all colors are at the relitive focus when they hit the TC, which may not be the case, because they are intended to be focused at the film/sensor plane, and may be slightly divergent before that point.

12-25-2007, 12:44 AM   #17
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Gulfer, you are da Man!
the TC seems to work rather well with your 18-250. it is really not so bad.
with the CA issue being amplified with TC, i wonder if PP will also take that out.
Just one more Q for you, Gulfer, did you take the shots at the low, high, or midrange of your 18-250 zoom?
I just love the power of enthusiasts in providing very useful information to the mass. Merry Christmas you guys!
12-25-2007, 07:44 AM   #18
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Those were all under a 100mm. This is with the 18-55 at 18mm.

This is with the Teleconverter at 18mm

This is without,,,,, 18-250 lens at 220mm

This With,,,,,18-250 at 130mm


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