Does anyone here know if the viewfinder loupe attachement of the EX3 would fit on the LCD-screen of the Sony HVR-Z7?
Or, to put it otherwise: which is the exact size of the LCD-viewfinder in the EX3?

The shell has a 4.5" diagonal. The screen itself is 3.5" diagonal. I'm not sure it would work well with the Z7, I think it's on the heavy side, if the hinge joint isn't stiff enough it might sag.

I think Hoodman is releasing a larger loupe in the next couple months for screens up to 3.5", that may be your best bet.

The shell has a 4.5" diagonal. The screen itself is 3.5" diagonal. I'm not sure it would work well with the Z7, I think it's on the heavy side, if the hinge joint isn't stiff enough it might sag.

I think Hoodman is releasing a larger loupe in the next couple months for screens up to 3.5", that may be your best bet.

I have been in touch with the people at Hoodman and they confirm approx 45-60 days for release of an attachment to the HoodLoupe 3.0 which will fit the screen. Personally I have found the current HoodLoupe fantastic working within the constraints of cutting off a portion of the image on the sides of the viewfinder (but not the vertical dimension).