Recently Wayne posted a very detailed post on how is used a vario-ND fillter and getting good results with LiveView on his IQ180. I read and re-read this post and then ordered the Schneider Vario-ND that Wayne referenced in the post.
The results were very impressive. Literally for the first time since I have used a CCD back with LiveView outdoors in normal light, I was able to see the screen without any blooming, and zoom in and out and still not bloom. I was able to obtain an excellent focus with LiveView and then confirm it with the LCD on the back.
WOW, it worked and actually worked very well. The 100% view is a bit noisy, at least on the IQ260, but you can get a good focus solution and it doesn't take a lot of time. This solution totally eliminated the troublesome blooming, once you dial the vairo ND to a dark enough setting.
1. I used this with great success on both my 40 HR-W and 60mm APO Schneider. I used the CF on the 60mm Schneider as I planned to use it during the shoot.
2. The CF on the 60mm Schneider has outer threading of 72mm, so I used a 72mm to 77mm setup ring to get to the 77mm diameter the Vario ND needs, and a 67mm to 77mm step ring on the 40mm HR-W. The rings I used were older ones from Kalt and Tiffen and both of these had trouble accepting the rear threads of the Vairo ND 77mm. I believe this will be fixed with a Heliopan brass step up ring.
3. I was not able to get enough light at F5.6 (widest aperture on the 60XL) with the CF on, so I just moved the switch on the Copol to which totally opens the aperture, then I had no problems.
4. Even in very bright afternoon light I was able to dial in a ND setting that stopped the blooming and allowed me to zoom in and out without blooming.
5. The frame rate is still slow, but you can work with it.
I have to say I was impressed, as this works!!. You can quickly and easily get a focus solution and use tilt and see the effect in Live View on the CCD backs using this setup.
Once again, thanks to both Wayne for the detailed information and the getdpi forum.