I was on a trip and made due with what I had in the moment. The
combination 180 + extension + 1.4x means the 1.4x adds magnification.
180 + 1.4x + extension adds focal length. If you increase focal length
first, then you need more extension to get close focus, whereas
extension before 1.4x gives closer focus plus magnification. The 180mm
gave enough working distance, so I did not need to increase focal
length for more working distance. Longer focal length increases working
distance, but requires more extension for close focus. So the simple
rule is, extension before teleconverter increases magnification,
teleconverter before extension increases focal length.
The 135mm macro on the auto extension tube probably would have given me
what I needed and would have been a more stable setup. At the time I
only had the 90mm macro, and not enough working distance. My kit at the
time was a choice to include the 180/2 + 1.4x for telephoto work.
Adding two 25mm extension tubes was a small addition to the kit, which
gave me greater than 1:2 macro as well. When you are out in the field,
working distance can be a make or break macro shot, especially with
skittish subjects. (~1:1.6 macro)
Also, from an esthetic point of view, the simpler your composition, in
general, gives a better composition; especially in macro work. The ways
to simplify composition are to blur the background and to narrow the
field of view. Besides working distance, longer focal length macros
reduce background clutter by reducing field of view. Even if you can
render the background out of focus with shorter focal length, it can
still be distracting light and dark blobs, so narrowing the field of
view is the best alternative.
I also had a C-5050 with me, and it will do very close focus, but only
when the lens has a fairly short focal length. When you can't get a
large lens + camera + big tripod near the subject, sometimes a small
digicam on a mini tripod will fit right it. But the wider field of view
due to shorter focal length will change the perspective of the shot.
Many various macro lens combinations will give 1:2 macro, but the
perspective, background clutter, etc. will be a lot different depending
on the focal length. (And the C-5050 is a hit or miss shot with macro
in auto-focus).
There was one other feature the 180/2 gave me, the longish arca swiss
style quick release on the 180/2 tripod mount also served as a sliding
rail. Macro focus is usually done by moving the lens relative to the
subject, rather than the focus ring. So I could also slide the lens
forward and backward to help focus on the subject, while the focus ring
providing fine focus.
As for optical quality, the 180/2 provides more light for critical
focusing, but since many macro shots are done with small F-stops for
increased DOF, there is usually little difference in image quality
between stopped down lenses, but I have not personally done any tests
and there may be something I am missing.
Wayne
At 03:25 PM 7/26/2004, Fernando wrote:
>Hi Wayne,
>
>Why did you find this setup preferrable?
>Is it just because of its stability, or are there optical reasons too?
>Find it difficult to understand the tubes in-between the 180/2 and the 1.4x.
>I hope to be trying a more modest setup [200/4 + 65~116 + 2X-A] in this
>style but would like to know the advantages a little better.
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