Fay,
I would add a proviso to Kelly's response: Although he is correct
about the extension tubes not causing any deterioration in the image
quality per se, there is another factor that will. The optics in
macro lenses are carefully designed so that various aberations
(spherical and chromatic in particular) are minimised when used for
macro work. This is not the case for your normal lenses where such
aberations are controlled over the more usual range of object
distances.
You will find that a macro lenses used close up will give better
results than a zoom lens used close up to start with (and that will
be particularly true when compared to a zoom lens with such a high
zoom ratio as the 18-200). When you move into the macro realm, that's
where macro lenses perform at their best whereas the use of extension
tubes is going to compromise the control of aberations built in to
the zoom lens because you are using it outside its design parameters.
Having said that, I've taken many a fine macro picture using the most
basic of equipment. Don't forget that reversing a standard lens (or
something close to it) on the end of just about any other lens allows
both lens to be used in their 'optically correct' configuration and
excellent macro results can be had thereby.
Grimble.
--- In NIKOND200%40yahoogroups.com">NIKOND200
yahoogroups.com, "Pastor Kelly"; <PastorKelly...>
wrote:
>
> Fay, since there is no glass in the extension tubes there will not
be image quality loss, however, you will find that the image will not
not have the light that it could have with a macro lens as macro
lenses typically have larger lens openings. I would also expect that
you can get a larger macro with a macro lens, but so long as your
tubes will allow you to fully utilize the 18-200 Vr, it should work.
> Kelly
> http://www.pbase.com/digital_kelly
>;
>
>
> ----- Original Message -----
> From: Fay Kelley
> To: NIKOND200%40yahoogroups.com">NIKOND200yahoogroups.com
> Sent: Tuesday, May 29, 2007 2:27 PM
> Subject: Re: [NIKOND200] Re: Nikon Macro Lens
>;
>
> Thanks to every who wrote ...
>
> Pastor Kelly wrote:
> >Fay, the 18-200 may focus up close, but it is by no means a
macro...
>
> I have a combination of extension tubes I can use singly or
together
> and can get as close as I want .....
>
> my question is is there a difference in quality using the 18-200
VR
> with extensions vs. a lens that is designed for macro with VR?
>
> if that makes sense....
> --
> Cheers, Fay
> http://www.faykelley.com
>; 928.600.1733
>
>
>
>
>
>
> ----------------------------------------------------------
----------
>
>
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.472 / Virus Database: 269.8.3/824 - Release Date:
5/29/2007 1:01 PM
>
.
