On Sun, 26 Aug 2001 13:49:42 -0400, you wrote:
>John, I was wondering what about the sideway support is of concern to you? I
>use the Kirk King Cobra head with my 600 and haven't run into anything that
>I'm concerned about with it yet.
>Ken Waller
My concerns are mainly theoretical, and probably
unfounded, since you are having no problems.
I believe the foot/collar assembly is just cheap cast
metal, very strong when handling compression loads but
relatively weak at handling loads in other directions.
I guess I would be afraid the tripod collar, under a
sideways or uppermost load scenario, would simply break
off at some point in its construction, sending the lens
crashing to the ground. I don't think it is a matter of
"if" it will break, just a matter of "when" it will
break - will it break in my lifetime or not is the
question I would be asking.
Looking specifically at the tripod foot of the FA^
600/4, it does not look as if it were designed to
handle the load except directly underneath the lens.
The bulk of the collar is in the foot, with thinner
"ears" extending out from the foot to cradle the lens
to about the four and seven o'clock positions. Along
this thin part, it attaches to the lens itself with a
couple of screws (BTW, these screws do come loose, so I
check them every outing). In a sideways orientation,
most of the weight is not directly supported; instead,
this weight exerts a lever effect on the thin "ears"
extending out from the main portion of the foot.
If your head manufacturer has tested a Pentax tripod
collar/foot to its design limits, then my concerns are
probably unfounded. But I ain't putting my big glass on
such a mount until I see some hard evidence that the
foot/collar assembly won't break off under normal
usage.
--
Happy Trails,
Texdance
http://members.fortunecity.com/texdance
http://members1.clubphoto.com/john8202
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