Macro equipment: macro lens or extension tubes?

Hi group
I have a Pentax Super A / Super Program SLR camera
I have a few lenses, including a SMC PENTAX-A ZOOM 1:3.5 35~105mm with
a macro setting
Minimum focusing distance for this lens however is 1.5 meter
Now I'm considering to buy some other equipment for better macro
capabilities (read: closer)
What should I buy? What results can I expect from extension tubes? Can
I use them in cooperation with my existing macro lens (maybe without
the macro setting)
Or am I better off using & 50mm lens together with extension tubes?
Or can I use close-up filters to be able to focus at a closer distance?
My primary interests are flowers and insects
Thanks a lot for your help

Stevenpalmaers@gmail.com

Re: macro equipment: macro lens or extension tubes?

I am experienced with macro work, back when I was using Canon manual.
I used an F1n (later model) which does *not have a mirror lock up, but
that mechanism is so smooth it doesn't need it (as is specialized with that
body), and the pictures came out very sharp. But that body is expensive.
It is still a better idea to have MLU anyway, and your's doesn't have it.
However, this can be done at budget with Pentax, if budget is a concern.
Pentax bodies that have MLU are K2 (best choice), KX (less features), LX
(luxury) and the autofocus Pz-1P.
http://www.robertstech.com/pentax.htm
http://www.pentax-manuals.com/
There are always nice ones of those on eBay. The K2 is a great one because
it has everything a camera body should have, except the ability to accept a
motor drive, unless it is a K2-DMD. The K2 also has a superb light meter
of a silicon photo diode (SPD), very advanced for it's time in the 70's, and
the most perfectly accurate. As well the batteries are still normally available
everywhere. Today I just put in a new radio shack 3 volt lithium cell for
$5.99. This replaces two 1.5 volt silver cells.
As well the lens you need, which is Pentax 100mm f/4 macro, these type
have a very flat field with no aberation, very fine glass. Extension tube
set, these couple the body to stopping down the aperture when shooting
and come in sets 3, 12mm, 20mm, and 36mm, if you want to go that far.
These measurements describe the added distance given between body
and the lens (and focal plane). The farther away the lens is from the focal
plane (film surface), the closer to the subject it can focus.
Another method is using a reversing ring, this has a bayonet mount on one
side and lens threads on the other, reverse the lens and you have serious
macro. In this case it is best to use a compound (one focal length) of 100
or 200mm, or a zoom lens that is known to be very sharp. If you do this
you can get some amazing results. I did it and got very tiny parts of
postage stamps quite quite sharp. This lens for me was a Canon FD 80-
200 two touch, ultra sharp.
These two previous ideas are really about genuinly "micro" macro
photography, I'm not so sure that's what you need, maybe just the K2.
But that lens you mention should be quite sharp, and work great with
a reversing ring, but I still recommend the 100mm macro by Pentax.
Have fun and don't buy generic lenses.
--
}<)))*> Giant_Alex
cravdraa_at-yahoo_dot-com
not my site: http://www.e-sword.net/

AAvK

Re: macro equipment: macro lens or extension tubes?

I would suggest getting a copy of John Shaw's "Closeups in Nature".
He gives a very good discussion of multiple methods of macro including
tubes, close-up lens (dual element), true macro lens, lens reversal,
lens stacking etc. After reading it, you might have a better idea of
which way to jump. And outstanding pictures to illustrate his methods.
Jay

Re: macro equipment: macro lens or extension tubes?

The one thing I've noticed is that Pentax tended to develop prime lenses
with somewhat wider maximum apertures once they ported over from M42 to
K-Mount.
BUT, from what I've seen on photodo, Pentax lenses are still optimized
pretty much at f/8, unlike Leica, for example, whose prime lenses are
oriented toward better performance wide open.
Whenever possible, I tend to shoot at f/8 and use the aperture-preferred
auto exposure to set the shutter speed. Fortunately, most of my work is
outdoors and in daylight, so this is not as big of an impediment as it might
otherwise be. When I want shallow depth-of-field, I just open up to maximum
aperture and if that results in softer resolution, that's just the way the
cookie crumbles.
I'm planning on getting the f/1.2 50mm A lens. I was agonizing over that
one versus the upcoming Zeiss 50mm f/1.4 M42 mount lens, and what tipped the
scale is the fact that the Zeiss lens has no autoexposure linkage,
effectively making it it most useful on a Spotmatic II. Somehow that seems
a bit antiquated to me. The f/1.2 should be a joy to focus, even if I still
shoot at f/8 . . . I've become quite pleased with the autoexposure modes in
my P3n and P30t, and I am not about to go backwards. Sorry, Zeiss . . .

Jeremy

Re: macro equipment: macro lens or extension tubes?

And in KA mount Pentax offered a 100mm f/2.8 Macro lens that's as good
or better than the 100mm f/4 screwmount lens [1]. Close focus is just
under 1 foot for 1:1. Stopped down one or two stops it's a killer lens.
It's also a pretty good portrait lens in 35mm and with Pentax's *ist-D
line DSLRs.
Like the screwmount lens it's not optimized for focus at infinity
(although it will - 1:25).
[1] My opinion, YMMV.

No_name

Re: macro equipment: macro lens or extension tubes?

I fully agree with the rest of Jeremy's excellent post, but I disagree
here: Non all lenses perform the same when used with extension tubes.
Many will give terrible results (compared to a "real" macro), but there
are a number of "regular" lenses which perform beautifully when used
with tubes or reversal rings (in the Nikon world, the 200mm f/4.0
outperformed the micro version and the reversed 24mm f/2.8 was outstanding).
While I wouldn't bet on your current zoom performing well with tubes,
you can probably find a number of Pentax primes which will.
In the true macro world, the Tamron 90mm has an excellent reputation and
may be cheaper than the Pentax 100mm (haven't tried it myself).

Chris Loffredo

Re: macro equipment: macro lens or extension tubes?

...
No other option will give you results as good as a proper macro lens.
I have both the 50mm and 100mm macro lenses from Pentax's screwmount line
(SMC Takumar) and they are superb. The 100mm lens especially is renowned
for its creamy bokeh and absence of light falloff at the corners. It has
excellent flat field coverage. Documents have straight edges, not barrel
distortion or pincushion distortion. The lens has a maximum aperture of
f/4, which minimizes optical aberrations (the faster the lens, the more
optical compromises must be made). Also it is optimized for close focusing,
not for infinity as are most other lenses. It has extremely high resolving
power and beautifully-saturated colors.
I bought mine several years ago on eBay for $100, but now I see them at KEH
and eBay for prices in the $300 range. If you are serious about macro
photography, a true macro lens is the way to go.
I believe that Pentax made macros in the A series with bayonet mounts, but I
never paid much attention to them, because I already had their excellent SMC
Takumar versions. They can be mounted with an adapter, and auto exposure is
not that big a deal, given the type of photography it is used for. But if
you can get a macro in the A series, by all means do so. I suspect it will
be more expensive.
I especially favor the 100mm over the 50mm, because the lens does not have
to be as close to the subject to fill the frame. That leaves some room so
you can properly light up the subject--important with things like insects.
As for your present zoom lens with "macro" setting, it really is not a
macro. Most lens makers intentionally misuse the word macro to include
those that can magnify the image to make it look like it fills the frame. I
have a couple of zooms that do that, but compare their results with those of
true macros and the differences are readily apparent.
But, since you already have a "macro" zoom, you probably won't see much of a
margin of improvement by using a normal lens with close-up lenses attached,
or by using a reversing ring. What you really want is flat field coverage,
excellent sharpness, absence of vignetting, high resolving power and smooth
bokeh--and that requires that you get a real macro lens, not play around
with compromise setups. You already have such a compromise available to
you, and you have expressed dissatisfaction with the results.
If you intend to take only casual photos and don't want to break the budget,
use what you have already. But I suspect that the desire for the real thing
will one day overtake you.