[EMAIL PROTECTED] wrote:
Hi Gang.
I did a Google on this but came up empty. Boz's site just mentions the clamp
but no
details.
So.
Can someone fill me in on what the clamp knob does on the lens.
I know what the focus range knob does.(if it does what the Nikon lens does,
then yes.LOL)
Thanks for any assistance.
Dave
Primarily to prevent rotation of the focusing ring when the lens is
focused manually and pointed down.
Quote from the Pentax FA lens manual.
"With manual close-up photography using the copy stand in any situation
or with the lens pointing down, if you turn the clamp screw to the ON
position, rotation of the focusing ring becomes tight. This helps to
prevent the rotation of the focusing ring due to the len's own weight
and avoid any shift in focus."
When the clamp screw is ON, the focus adjustment also seems to be
stiffer when the lens is pointing down then it is when the lens is
pointing horizontal. You can test this without the lens attached to the
camera.
--
David S.
Nature and wildlife photography http://www.sheppardphotos.com
