At 00:02 5/8/01, Joel Wilcox wrote:
Wow. Thanks.
You're welcome. Researched some of this stuff for a tutorial on my web
site about lenses. Not yet complete, but getting there.
I've got the Viv tubes. I'm not thinking about using the 135/2.8 on the
notion that it would be faster but because the lens seems to me to be very
good. Also, all being otherwise equal between the two, if the 135/4.5
allowed me to stay further away from the subject, I would find this to be
a selling point. I don't do well stalking butterflies even with the 90/2.
Jumping to the 135/2.8 with extensions will require a steadier hold
compared to the 90/2 if you're doing this hand held. Should be lighter
than using the 90/2, although heavier than an 85/2 with tubes.
I've had some good experience using the 300/4.5 with a little extension
for close focus at a good working distance, but not handheld.
I've used the 200/4 Zuiko with extensions also, although not as often as
the 85/2 and 135/2.8 lenses. As focal length is increased to gain distance
from subject, the length of extension tube required for the same
magnification is likewise increased.
Thinking out loud:
I ought to put together a table showing what the various combinations tube
lengths do with various Zuiko prime lenses; both with Oly tubes and the
Vivitar. Found the longest tube out of the Vivitar set, the 36mm, quite
handy with the longer lenses. Wouldn't be hard to do in a
spreadsheet. Results would be approximate measuring from lens exterior as
the theoretical formulae are based on distances from lens principal points
(nodes) and film plane. Might be useful for some as the TOPE 6 window is
still open (have you done yours yet?).
-- John
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