I only read the digests so I hope no one has answered this already...
One plus of having instant message delivery (e.g. with eGroups) is that
people could tell if someone else has already responded to a question
so there won't be 15 identical answers. Anyway...
I've got the 65-200mm, a 25mm extension tube and the 65-116 tube. I've
used them together a few times and had good results. You can calculate
the magnifications without actually trying it out though. The magni-
fication factor for a lens is just the total amount of extension divided
by the focal length. For example, the helicoid in the 50mm f/3.5 provides
up to 25mm of extension allowing it to go to 1:2. That's why adding the
25mm tube takes it to 1:1 ( (25mm built-in + 25mm tube)/50mm ). However,
the minimum magnification is now 1:2 ( (0mm built-in + 25mm tube)/50mm ).
The 65-200mm goes to 1:3 by itself (only at the 200mm length), meaning
that the lens itself can provide up to 67mm worth of extension. Now you
can calculate the magnification factors available:
65-200 (at 200) w/ 25mm tube:
Min: 25/200 => 1:8
Max: (67+25)/200 => 1:2.17
65-200 (at 200) w/ variable tube:
Min: 65/200 => 1:3.1
Max: (67+116)/200 => 1:1.1
This is all based on formulas but a quick check with my equipment (look
at a ruler through the viewfinder) shows that these are all approximately
correct. In fact, I'd trust the formula since I'm using an OM-10 with
a stupid 93% viewfinder. The 65-200mm behaves a little oddly at the 65mm
end though. I can't really explain it, but turning the focus ring with
the variable tube on does not significantly change the magnification. If
anything, it decreases the magnification. Weird. My best guess is that
it doesn't truly stay at 65mm. Just a guess though. Anyway, empirically,
it pretty much behaves as if the lens has no built-in extension at 65mm.
Thus, we get:
65-200 (at 65) w/ variable tube:
Min: 65/65 => 1:1
Max: 116/65 => 1.78:1
Jason "new to the list" Miller
>Has anyone had any experience using either a 65-200mm or 200mm lens
>and either the fixed extension tubes or the 65-116 variable extension
>tube for close-ups. Can someone tell me what the magnification range
>would be with these various options?
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|