Using tripod ring to level camera

[nathan_cenower]

<p>I just began using a canon 300mm f2.8L IS lens mounted to my gitzo/3531, markins m20 ballhead, wimberley sidekick combination for shooting birds in flight. I level the camera by loosening the tripod collar and rotating the camera body in the collar- then re-tighten the collar screw. Thus far this seems to work OK.<br>

I'm wondering what added benefit, if any, would be achieved by adding the gitzo 5121 levelling base?</p>

[Ed_Ingold]

<p>A leveling platform makes it easy to make the axis of panning rotation perpendicular. If the axis of rotation is not vertical, the camera will change level as you pan. If there were an horizon, the angle of the horizon would change. It probably makes no difference for a bird in flight if there is nothing in the image which references the horizon.</p>