Re: L plate for *istD

[Herb Chong]

they are for different purposes. the RRS clamp replaces the camera 
attachment on your existing ballhead and changes you over to the Arca-Swiss 
style QR system. since the rotation mechanism is on the top of the head, it 
can be leveled with the ball head lock and will rotate while maintaining the 
level. the Acratech head allows you to use standard tripod screw thread 
attachment to your camera. the rotating base is at the bottom of the head 
and will rotate about the axis of the tripod mount. in general, this will 
not be level unless you level the entire tripod. depending on the type of 
tripod you have, this may be easy or hard. 5 or 10 degrees inaccuracy is not 
going to make a difference in a panorama stitching program.. you usually 
need to overlap 30-50% to get good results. if you read further on the RRS 
site on creating panoramas, or on other sites such as Panoramic.net or 
panoguide.com, you will see that you need a ballhead with a rotating base 
and a panoramic rotator in addition. attaching the RRS pano clamp 
permanently to the Acratech head, if that is the one you like, is what will 
work best. you will still need an L-bracket system, and ideally, you will 
want one with fore-aft movement too so that you can set the nodal point, 
which an L-Bracket on a panorama clamp will not let you do.

Herb....