I custom made this viewfinder after using the hoodman loupe on my 5d Mark II. I found that it was very uncomfortable and hard to keep in focus. Then I tried the z-finder from zacuto at abelcine. it does have a great feeling and the optics are great. problem is it is out of stock all over town, not to mention price point. what was great about it was the eyecup and the 3x magnification. since i'm a do it yourself type of person, i decided to go out and try to make one on my own. i went to calumet and found this amazing 3x loupe. to my surprise it was exactly the same image as the zacuto. actually i thought that optics were better! and at $160 more than half the price. since i had already placed velcro around my LCD from the hoodman all i had to do was place the fuzzy side around the edges of this unit. it fit perfectly. the glass is german engineered rodenstock. but the design of this loupe was even more interesting.
as you can see when you pull off the top half what's left on the camera becomes a sunshade! it clicks on tightly when its on and easily comes off when you dont need it. brilliant. so all i did was go and buy i used eyecup from an old JVC camera ($15) that fit perfectly on the unit. total cost $175. the square unit is too big for the camera so i might actually create a connection piece for it that will retrofit the part that connects to the camera.
highly recommended if you want to great option from the zacuto!