Ok, here goes! This is my diffuser design. Like the one from gardenerassistant, this design emphasizes reflected light more than diffused light. Its a thing i've been evolving for two years now. Already laying awake in bed, worrying if my diffuser is adequate, but that is the way it goes!
I was long ago drawn to the versatility of these wonky-looking twin flashes. One can control the direction of lighting, and since the diffusers are easily designed to not be attached to the macro lens one can easily switch out lenses in the field.
Twin flash diffusers. Front view. by
Mark Sturtevant, on Flickr
A twin flash allows more directional control of light. by
Mark Sturtevant, on Flickr
A. The diffuser bowls are cheap items bought from a party store, and are 7 inches across at the front. The face of the diffuser is a thin layer of wrapping foam (~ 1 mm thick), plus there are some extra layers in front as a last-ditch effort to discourage hot spots.
B. The back of the diffuser. I know it looks very messy. Dremel cutting tools were used to cut a T-shaped hole in the back of the bowls. This was to fit the T-shaped flash head. Accessory holes were also drilled alongside to receive zip-ties. There is foam padding to seal in the light. The scrap of duct tape is left over from an old diffuser design. Zip-ties are threaded thru the holes and around the stem of the flash heads. These hold the diffuser to the head
very firmly.
C. The T-shaped pattern that was cut into the back of the bowls, plus the accessory holes.
Twin flash with new diffusers by
Mark Sturtevant, on Flickr
D. The front foam layer is removed to reveal an inner foam layer. The entire interior is covered in shiny HVAC tape.
E. Full interior view, showing the heart of this whole design which is a wedge-shaped deflector suspended in front of the flash head. The deflector is shaped out of card stock paper, and covered with HVAC tape. It is sized to more than eclipse the flash head when seen from the front. The idea here is that
no light from the flash can get to the subject without reflecting off of HVAC tape. Hard to see, maybe, but the deflector is held in place with “spider vanes”, much like how a secondary mirror is suspended inside a reflecting telescope. It does not touch the flash surface, and yet its held firmly in place.
F. Schematic showing the deflector. Note that all 4 sides are angled to reflect light away.
G. Schematic showing the overall diffuser design again.
Secret interior design of diffuser. Shhhh. by
Mark Sturtevant, on Flickr
Lets see how this works!
All of these were focus stacked by hand from a small number of pictures. Only the last one was done indoors in a staged setting. Other than stacking, only light editing was done (cropping, unsharp mask), to better show what I get from this current rig.
Pink ladybug. This one is dead, having been parasitized by a tiny wasp. I will post more on that later.
Pink ladybug by
Mark Sturtevant, on Flickr
Cute little tree hopper. I see these on goldenrods. This is a male, I think, and i suspect the pattern on the rear end is a "false head". There are tree hoppers that try to fool predators into mis-identifying where the head is.
Plant hopper stack by
Mark Sturtevant, on Flickr
Jumping spider. This might be a new species for me.
Jumping spider stack by
Mark Sturtevant, on Flickr
A tortoise beetle. Note the "teddy bear" markings.
Tortoise beetle by
Mark Sturtevant, on Flickr
"Studio" shot of a Chrysomelid beetle. The picture on the left is taken at one stop greater flash power than the picture on the right. I think the super bright reflections on the thorax came from the modeling light I was using.
Red chrysomelid comparing flash power by
Mark Sturtevant, on Flickr
Known issues in this design:
1. One usually gets two highlight areas rather than a single one. This is especially noticeable in eyes. I always get two very distinctive bright spots in very shiny eyes like the spider eyes shown above. I've wondered if this is an artifact produced by the eye lens itself, where light reflecting back from the interior of the eye is focused by the lens of the eye.
2. I wonder about the shape of the bowls. The swooped, curvy shape might mean that more light comes out from around the center than from the periphery. Designs to try later would be either hemispherical bowls, or straight sided cones. Not sure where to go with that.
3. I need to work on more 'frontal' lighting. One can see especially in the ladybug and the Chrysomelid beetle how the insect parts facing the lens are rather shadowed. So maybe I should try some kind of reflecting baffle in front that hangs down alongside or below the lens.