In article ,
Eric Stevens wrote:
On Mon, 10 Dec 2012 19:31:03 +1100, Rob
wrote:

On 10/12/2012 7:01 PM, Paul Ciszek wrote:
All of the tripod collars I can find for sale list the lens they are
intended to grip, but never the size. I am quite certain that there
has never been a tripod collar for the teleconverter I want to grip,
so I was hoping to shop by size and "wrap" the teleconverter to make
it fit.

Whats more I don't think there would be enough strength in the converter
shell to enable the collar to tighten.

What's wrong with clamping on to the lens with which you are using the
teleconverter? It is almost certainly made to be supported in this
way.

That is in fact my plan B, but the reason is simple: The center of gravity
of the camera-teleconverter-lens combo is closer to the teleconverter than
to the only grippable area of the lens.

The lens is a Tamron 55BB mirror lens. The 55BB, unlike its predecessor,
was not designed to have a mounting bracket. Focusing rotates almost the
entire barrel except for a portion approx. 3/8" long. This part of the
lens is slightly forward of the center of balance of the camera+lens combo
even when there is no teleconverter, and is even further forward of the
center when the teleconverter is added. The teleconverter is a Tamron
140F; since they no longer sell the adaptall mount version, I had to get
a Nikon mount version and add an adapter, but it seems to work. (The
Tamron 140F was meant to work hand-in-glove with Tamron lenses like the
55BB; that's why I went to the trouble.) The camera is an Olympus OM-D.

I think the 140F is sturdy enough to be gripped. If the mounts on either
end of it can't hold up the weight, then I am screwed no matter where I
grip the combination. I do think it makes more sense to hang the camera
off of one side of the teleconverter and the mirror lens off of the other
side than it does to either hang the whole thing one-sided off of the
camera or the lens.

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