neuroanatomist, interesting comment on the levelling base. I have asked a few folks about that, and I have gotten mixed responses - a couple of folks have suggested that it is a "good thing" and others have indicated that it was "unnecessary". I guess time will tell, although, I have no recollection of seeing anyone with a gimbal on a Gitzo that had a levelling base. I will go without for now and see if it does become a requirement as I can always add it later
Yeah, perhaps 'need' is too strong a word. It depends on your shooting style, in part. If you are a 'go out, set up once, take lots of shots, tear down, go home' shooter, there's not much advantage. I often grab the setup and move a few feet (or tens of meters) then set it down again. To have to re-level each time using the legs would be a real pain, as Rich states.
I suppose there are three options:
1) Leveling base.
2) No leveling base, just level the legs each time - that's hard to do with a supertele mounted on the gimbal, and there's a risk of tipping the whole thing over while lifting a leg to extend it.
3) Don't level the platform. Whether or not this matters depends how and what you shoot. If the base of the gimbal is tilted, your shots will be tilted, too. Now, if you're mainly using the gimbal for vertical movements of the lens, you can loosen the tripod ring and rotate the lens to straighten the frame. But if you pan horizontally, you will get progressively more tilt as you pan, unless you're leaving the tripod ring loose and rotating the lens as you pan (possible, but probably not easy to do well). If your framing is loose, you can level in post - but I prefer getting it right in-camera, so you don't find yourself having to crop out something you want as you level the image.
I wonder...of the people who indicated that it's unnecessary, how many of them have used one? I know a few people who have claimed that a gimbal is 'unnecessary' for a supertele, because as long as your ballhead supports the weight, that works fine. Then they actually try a gimbal and.....
Having said that, it does make sense to try without first, then add if you think it would help.
I spent a little while yesterday afternoon at the edge of a copse of trees and bushes with a lot of small bird activity. I had to frequently move the tripod around on pretty uneven ground to get better angles, depending on the activity. The leveling base made that a lot easier to do.
I can also definitely confirm that a leveling base would be nice with the super-telephoto...I don't have one yet but I do plan on purchasing one from RRS.
Rich, do you also have a ballhead that you use with that set of legs? If so, you might look at the RRS leveling base w/ clamp. The TH-DVTL40 plate is sized for the Wimberley II base. The clamp not only makes switching from gimbal to ballhead easy, it also makes setup/breakdown faster. Also, you can get away with no ballhead if bringing a standard lens along - the RRS side gimbal can mount an L-bracket to use a standard lens, but the full gimbal and Wimberley cannot. But, the leveling base clamp is a standard AS clamp, so you can just clamp in a camera base plate or L-bracket - granted, you have limited position control - but it can save weight on a hike...