On Thu, 24 Sep 1998 23:45:14 -0500, ed romney wrote:

>Does a film taken with a 2 x Nikon converter on a quality Nikon 50mm
>F1.4 lens resolve better than the same target taken with the 50mm lens
>by itself and enlarged 2x either photographically or digitally? We need
>data both full open and about F4 (or F8 with the converter). Opinion is
>not enough.

A couple of things... The Nikkor 50mm f1.4 has fairly good resolution
at f1.4, but not especially good contrast (both improve by f2, the
contrast a LOT); the f1.4 lens will not meter properly on a converter,
since these are essentially f2 devices (changing the exposure
compensation or ASA works, though...); performance of even the best
(short) lens on the best 2X (short-lens) converter in even the best
combinations is rather poor wider than about f5.6 (f11 effective), where it can be acceptable (excellent at f11 or so [f22 effective...]).
So, the answer is: the 50mm shot at f2.8 and the results enlarged
2X will beat the 50 shot at f1.4 [f2.8] on the 2X converter; and
I suspect (though it is a closer call here...), that the 50, which
is really first-rate f4-11, will still beat with 2X magnification
the same lens on a converter and used at f4 (not quite within the
range of OK with the converter)...
BTW, in the digital domain (for small images...), lots of ills
can either be diminished (try masking in/out areas and using
"unsharp mask"...), or won't show in the first place due to
the limitations of the medium...

>We need a real test and these Nikon converters cost too much for me to
>buy on vague expectation of good results. Can someone send me a good
>jpg or else...some TMAX negs or slides by snail mail??. I'll share them
>with anyone interested. I began to wonder a while back when I found a
>negative taken with the Yashica 50mm F1.4 at F2.8 enlarged 4x was
>sharper than the same thing taken with the 35-210mm Tamron SP F3.5-4.2
>zoom full open at 200 mm. Shutter speed was 1/1000 sec. This is a cheap
>zoom, I know, but I bought it just for use in a part of Europe where
>good equipment has a good chance of being stolen. I am finding Sprint
>Scan digital enlargements of good prime 50mm lens images are
>extraordinarily sharp. What will a good teleconverter do with them?
>Yours faithfully, Ed Romney

I have a couple of Nikon TC200's I'd sell for a hundred $'s each...;-)
(The short-lens 2X converters are primarily useful for macro work
at small stops, I find - though the long-lens converters on the
big ED lenses can be good with the lens wide open, and really
excellent by f5.6.) The 1.4X converters are better for lengthening
FL's for other uses...