So, I search for a parabolic dome shape similar to Broncolor ones, if you know them, with the same fall off from a beauty dish and to restrict the light angle to a max 40-50 degree without having a grid on.
I found myself after a long search in DIY shops that there are not too much options. Finally I've chosen an industrial light reflector body made out of aluminium with a diameter of 41 cm. Not too small but surely not big enough, but somehow within the range to allow a small angle of light due to proportion between diameter and depth.
First intention was to use silver effect of aluminium, so I've started to grind the interior with a steel wire disc. Successful failure! The surface become grayish muddy. The only option to revitalize that will be a electrochemical anodizing, that I am pretty sure will crisp to max the images. As I have no anodizing workshop at the end of the street :-) I've chosen to save this and paint it in mat white.
I have painted in black mat the outside as well the components and finally I use a connector that allow me to use the reflector both on monolight with universal ring as well as with speedlights using the classical "L" shape connector with sphere.
A big part of the time I've spent to choose the right deflector both as shape as well as transparency grade. This part of the whole assembly have a crucial impact in the quality of the dish's light. It can change the white balance, affect the exposure, fall-off depth of shadows, reduce or enlarge the angle of the light (due to position and diameter), etc. I made 3 deflectors and still I am not happy with the end result. I end up using a bottom of a plastic barbecue dish (2 dish overlapped to increase thickness) which also allow the light to pass through. I am still looking for other deflectors and I will keep the ones with best result.
I've done some test comparison with a 60x60 cm classic soft box with internal diffuser. The results are comparable, with a more crisp look on the reflector dish. Unfortunately, the spread of light is around 90 degrees, so I might need to think on a grid.
Below, are the images of the ready DIY product and some images done immediately after I made it. I will need to test it on an adult face to see the real quality of light as well as with speedlites, in the near future.
Light setup: reflector dish used as main light but put on the side 45 degrees mostly as a rim light. Generally beauty/reflector dish is used as direct frontal light with small variations on the angle. I choose this solution to avoid light spread on the background and a flat look of the scenery.
I have also 2 lights red&blue as background and rim in the same time plus a snoot for face and a small silver reflector almost opposite to reflector dish.
Hope you will enjoy it and will give you the courage to experiment your own light modifiers.
And the images with my son playing on guitar.
Sorry for the background (cracked paper, but not care so much on this now).
I prefer black and white :-)