Do Specs for a Matte Box exist?

[Crafters of Light]

In reviewing many of the plans here for a DIY Matte Box, I have noticed one thing. There seems to be no fixed Dimension ratios. There are square ones as well as rectangular ones. I understand that these choices are based on the materials used for creating these items. Is there a ratio "formula" that one should try to follow? Or does it not matter? I see that in most cases they are designed around allowing use of standard 4"X 4" filters. And the one common denominator is they all seem to be quite a bit larger the the camera's lens aperture they are being designed for/used with (again most likely due to the chioce to add filters?).

I am toying with using a spare lens hood for my camera as a base and just adding adjustable flags to it. This in an attempt to help block light causing lens flares. Not really interested in the filter aspect as I use screw-ons anyways.

Aside that I may run the risk of vignetting of the flags at some point, am I missing any other issues I might be causing?

 

[Ted Ramasola]

The ones i made are designed not for the expensive 4x4 but cheaper chinese and cokin P series filters. The rule of thumb I used to base the angle/dimensions of flag size and hinge location is based on my widest lens, in my case the tokina 11-16.
And then there's the diameter of the fattest lens front for 35mm, in most cases it would be 82mm, so these considerations are among the factors taken into account in looking for materials for making a mattebox.