extension tubes with macros for critters?

Hi,

I'm going to Gabon for a month in the rainforest and I was wondering if
you could help me decide whether or not to buy a Kenko extension tube
set for my macro lenses. The gear to be used for close-up work is:

Minolta Dynax 9
Sigma EX 105/2.8
Sigma EX 180/3.5
Minolta 5400HS flash

others: Sigma EX 2x teleconverter, tripod, off-camera flash bracket

The 105/2.8 lens focuses to about 31cm but for some smaller critters
such as ants this is not enough, and to get in-yer-face pics of
caterpillar heads, for example, that simply is inadequate. So the
question is:

is the use of extension tubes to get closer to the subjects a viable
option?
is there a significant loss of optical performance?

help appreciated,
cheers,

Marko

is the use of extension tubes to get closer to the subjects a viable
option?

Yes.

is there a significant loss of optical performance?

No, only Depth of Field. Extension tubes are hollow so there is no
glass there to degrade the pic.

"Annika1980" wrote in message
oups.com...
is the use of extension tubes to get closer to the subjects a viable
option?

Yes.

is there a significant loss of optical performance?

No, only Depth of Field. Extension tubes are hollow so there is no
glass there to degrade the pic.


While that's true, most lenses aren't designed for close focus, and some
will perform better than others in that capacity.

--
Regards,
Matt Clara
www.mattclara.com

Matt Clara wrote:
"Annika1980" wrote in message
oups.com...
is the use of extension tubes to get closer to the subjects a viable
option?

Yes.

is there a significant loss of optical performance?

No, only Depth of Field. Extension tubes are hollow so there is no
glass there to degrade the pic.


While that's true, most lenses aren't designed for close focus, and some
will perform better than others in that capacity.

--
Regards,
Matt Clara
www.mattclara.com

And some will preform much worse. If the lenses you have are very
sharp then you can use extension tubes with some success. Otherwise a
big soft image isn't much better than a small soft image.

Bear in mind shallower depth of field, more susceptibility to camera
shake, inherently unreliable flash metering, if you are really
"chasing" critters they will be moving too.

Extension tubes are great for a number of things, but a better, I.E.
closer focusing distance, macro lens may be a better investment.

Be prepared to take multiple exposures as your keeper rate will go down
too.

If you get the extension tubes make sure you take some time to
experiment with them before you go and play in the field.

Jim

"etosha" wrote:
is the use of extension tubes to get closer to the subjects a viable
option?

Yes. Tubes are more rigid than a bellows, both mechanically and
functionally; you might want to consider owning both.

is there a significant loss of optical performance?

That depends on the lense. Many macro lenses earn that title
only by being able to focus close. The best macro lenses are
also optimized for use at close focus distances (as opposed to
being optimized when focused at infinity).

Note that some lenses that are optimized for close focus use a
floating element in the optics which moves in relation to other
elements as the focus is changed. For those lenses the added
extension from a tube or bellows is *not* compensated for; in
addition, unlike other lenses it will make a difference where
the lense's own focusing mechanism is positioned.

Consider, in addition to tubes/bellows, obtaining a "reversing
ring", which allows the lense to be mounted backwards. For most
lenses that will provide a sharper image because it is closer to
the image ratios the lense was designed for.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

"etosha" wrote:
thanks, everybody, for the answers. I googled a bit, but could not find
a Minolta AF 58mm reverse ring (the Sigma EX 105/2.8 is a 58mm lens,
magnification ratio 1:1). Do any of you know if they exist? How about

You'll need to use whatever reverse adapter you can find (49mm??) and
adapter rings to reduce the 58mm to match the reverse adapter. It
looks like 58-55mm or 58-52mm, and then either 55 or 52mm to 49mm would
work. The step down adapters are $5 each. See eBay item 7593103793
and take a look at their eBay store (Fotodiox).

I've bought several adapters and such from them and have been happy
with what they've sent.

using a coupler reverse ring 58 to 77 between the Sigma 180/3.5 (77mm)
and the 105/2.8 (58mm) lenses?

See eBay #7592735627.


--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

etosha wrote:

Hi,

I'm going to Gabon for a month in the rainforest and I was wondering if
you could help me decide whether or not to buy a Kenko extension tube
set for my macro lenses. The gear to be used for close-up work is:

Minolta Dynax 9
Sigma EX 105/2.8
Sigma EX 180/3.5
Minolta 5400HS flash

others: Sigma EX 2x teleconverter, tripod, off-camera flash bracket

The 105/2.8 lens focuses to about 31cm but for some smaller critters
such as ants this is not enough, and to get in-yer-face pics of
caterpillar heads, for example, that simply is inadequate. So the
question is:

Is the 180mm f/3.5 above the "macro" version?

A friend of mine uses one with the Maxxum (Dynax) 9 with excellent,
sharp, contrasty macro results.

I use the 100mm f/2.8 macro (Minolta) to equally fine results. I would
be tempted to aquire the Sigma 180 f/3.5 macro as well, but other lenses
are higher up on my list.

For _really_ close macro, the 1-3X Minolta f/1.7-2.8 (50mm I believe)
macro lens is the one to get although it might be difficult to find in
the new or used market and it is very expensive (US$1,500, grey market,
B&H).

It requires a very disciplined approach to the work that might try the
critters patience before you get the shot. The zoom is motorized for
very fine control. Also difficult to light the shot with flash as
you're very close to the subject.

Regrettably, Minolta macro (ring) flash is extremely expensive. I'm
hoping to find a Minolta ring flash kit on the used market or perhpas
get the vivitar version.

is the use of extension tubes to get closer to the subjects a viable
option?

Of course.

is there a significant loss of optical performance?

As others have pointed out you need a fortuitous match of lens and tube
length to get great results. The tubes are relatively cheap (Kenko) so
it's a good risk to take and can always be sold used for a small loss if
they don't work out for you.

If your 180 and 105, above, are the macro versions (the 105 must be with
35mm close focus) I'm not sure at all that it can be used with ext. tubes.

Cheers,
Alan.


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Hi Alan,

The Sigmas I have are macro lenses and pretty good as such. I found a
site exploring the use of extension tubes with the Sigma EX 105/2.8
macro. It's hard to tell from the scan whether the sharpness of the
combo is acceptable or not. Might give it a try, though.
The test is he
http://mypage.direct.ca/s/selliot/macro.html

cheers, Macromarko

etosha wrote:

Hi Alan,

The Sigmas I have are macro lenses and pretty good as such. I found a
site exploring the use of extension tubes with the Sigma EX 105/2.8
macro. It's hard to tell from the scan whether the sharpness of the
combo is acceptable or not. Might give it a try, though.
The test is he
http://mypage.direct.ca/s/selliot/macro.html

All of the ones with the TC's are a bit soft. It would better to post
full size crops of the images to really discern sharpness with the
extenders.

IMO it is is not useful to use the tubes (no sharpness loss if well
matched to the lens) with TC's which always have a sharpness price
regardless of quality.

[ In replies on newsgroups it is best to include the "Alan wrote:" and
relevant portion of the post you're replying to such that context and
attribution are maintained. ]

Cheers,
Alan

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-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.

Annika1980 wrote:
is the use of extension tubes to get closer to the subjects a viable
option?

Yes.

is there a significant loss of optical performance?

No, only Depth of Field.

-And light loss.