You won't be able to. It turns out that because the secondary is so fast you won't be able to do any better than f5 total and even that is marginal. I used an ST7 with a CFW8 could only use the TV .8 reducer (which gave me approx. f5 or 6.3 x .8) and even then I got some vingeting in the corners... If I used it without the CFW8 (about 1" wide) then most of the vigneting went away. Turns out that you probaly could make it work IF you had the F10 version and went down to f3.3! Hope this helps...
Chris Woodruff
www.ccwoodruff.com
Chris Woodruff
www.ccwoodruff.com
