>>The problem is not with the optics (the 85mm f1.4 Nikkor is sharp on
>>both converters [when used with understanding of their limitations]),
>>but with the speed of this or any other lens faster than about f1.8-2.
>>- metering becomes inaccurate unless compensation is made.

>I only remembered that the book said there was a problem, but this does sound
>like what it said. Any idea why the TTL metering has a problem with this?

Hi-- It's not the TTL meter, it's the converter - its glass diameter is
great enough to keep f2 lenses f2, but faster lenses are "slowed" by the insufficient diameter of the converter glass. Hope this helps.
David Ruether