Hi Peter, On Sun, 5 Jan 2003 23:39:40 -0800 (PST), Peter Jansen wrote:
> >Has anyone used the newer Sigma 1.4x & 2x AF APO >teleconverters with a Pentax prime lenses? How does >the image quality compare to the Pentax A-converters >(especially the L ones)? > I also have the two Sigma 1.4x & 2x AF APO converters, but have not used them much with my A* 300mm f/2.8 because that is a manual focus and the Pentax -L ones are simply better. Allthough the sharpness and contrast with the Sigma's is quite good, I found that used with the "big glass" wide open, they cause some vignetting. The Pentax -L converters do NOT (or not noticably anyway :-) They have a bit larger diameter as the Sigma. Stopped down, the Sigma's are quite good ... >I've read that the Sigma's are only compatible with >the FA* 200mm f2.8, 300mm f2.8 & 600mm f4. > That could be, there is a compatibility chart delivered with the converters, but I don't have them handy now. The might not work with all lenses becaise the front element of the converters lies almost at the mount level, so it might hit the rear-element of the lens on some ... >FYI: I've used the Pentax 1.4x-S with my F*-300mm f4.5 >with excellent results. It is very sharp. Just don't >use it against a blue or homogeneous light sky/area >since it vignettes slightly (very slight; may bother >some). Other than that the results are professional >quality in terms of sharpness/contrast. > Sounds like the Sigma's :-) >Boy I wish that Pentax would come out with AF >converters SOON. They should forget any further lens >development until they release AF teleconverters >IMHO!!! > Well, I don't have AF big glass, so I'm happy for now :-) >Anyway, any info about Sigma (Stigma) converters would >be great. Thanks. You're welcome, Regards, JvW ------------------------------------------------------------------ Jan van Wijk; http://www.dfsee.com/gallery
