Mattebox options with rotating front element?

[elubes]

Anyone have ideas on how they're using matteboxes with rotating front element anamorphics? Especially when pulling focus? Sometimes I'm not looking for flares and just want a clean image.

Flexible donuts get twisted up and clamp ons obviously dont work. Also, reduction rings don't really work when the front element of the lens moves forward (not the rotational aspect but on the z axis) because they limit movement.

I can't think of any way to solve this...
Thanks

[macdonaldz]

why don't reduction rings work? does your anamorphic extend more than rubber bellows allow? they generally have a good 4 or 5 cm of extension/compression.. i've never seen bellows create a noticeable push on lenses with extending fronts (old standard speeds is what comes to mind)

[QuickHitRecord]

The slider base from here: http://www.lockcircle.com/matbox/buy/

 

And a set of "nuns knickers" like this: 

 

Would probably get you most of the way there.

[elubes]

yeah my anamorphic/iscorama (with the close focus mod) extends pretty far forward from infinity down to 4'.  so the reduction rings don't work. 

 

 

that sliding mattebox is pretty cool.

 

not sure if the nuns knickers will though b/c the throw is so large on my lens that it'll just get twisted up from front element rotation.

thanks for the leads.

-e

[QuickHitRecord]

A simple solution might be putting an 82mm lens hood on a step ring and attaching that to the front of your Iscorama (72mm thread if I remember correctly). You'll have to experiment to see what vignettes and what doesn't.