[EMAIL PROTECTED] said:
> Is it possible to use this extension ring in other lenses?, in which
> lenses works best (i.e. wide-angles, teles...)?,
Yes, the PK-13 (and all the other extension rings) are usable on any
lens, and since there are no optics in it, will generally give the
best macro results possible with a given lens.
> Is it difficult to use ?, i.e. does the focusing and metering differ
> very much from shooting without extension ring?
You don't say which body you have, but the PK-13 supports only AI
meter linkages (the older M ring had the non-AI linkages). If you
have an AI metering body, the lens plus PK-13 will meter exactly as
you are used to with the lens alone. Focusing is also un-affected.
With a non-AI body, you will be in stop-down metering mode.
> I have at present the following lenses: 24/2.0; 35-70/3.5; 50-135/3.5.
> From the little I know, the smallest focal length of the lens gives
> a stronger macro effect. Would that mean that with the 24/2.0 I would
> get greater magnification than with the 55 micro?, or may be the lens
> has to be one of these "micros"?
Well, generally speaking, putting an extension ring between a lens and
a camera body is taking the lens outside its normally intended optical
envelope, and certain lens aberations may be expected to worsen. For
some lenses, particularly moderate aperature normal lenses, this degradation
is minimal, but zoom lenses and fast wide-angles are already difficult
to design, and putting an extension tube in there will not make there job
any easier. That aside, you will prbably have the best luck with your
50-135/3.5, as it is a good performer. Many people use the shorter
nikon extension tubes like PK-11 to improve the close focussing ability
of moderate to long telephoto lenses.
The 24/2.0 (which I own, and shoot most of my photography with) will
not be too happy on the PK-13. Firstly, the subject will have to be within
1cm of the front lens element to be in focus! To use such wide-angles
as macro lenses, one generally has to reverse them, and still the subject-
to-lens distance is very minimal. Yes, the resulting magnification is
extreme, but my experience with the 24/2.0 was that the image was quite
soft. The 20/2.8 is supposed to be good in this role, and has a special
reversing ring to match its 62mm filter size.
> The 50-135 has a "macro" function.... would that be enough?
Well, the "macro" feature of this lens should indeed be kept inside
quotation marks. Macro is normally considered to require at least 1/4
magnification. The 55/2.8 alone will go to 1/2 mag, and the PK-13 brings
that up to 1:1. There is a _world_ of difference between this and the
so-called "macro" mode of a zoom lens.
To sum up, the 55/2.8 is a great macro lens, and the PK-13 a useful
accessory.
grant..
