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| p.1 #1 · Another DIY Diffuser (Mk3) |
I'm always on the lookout for DIY diffuser materials and today I found some table place mats which are black on one side and matte silver with a textured pattern on the other. I used them to create a "Mark3" iteration of my diffuser. I don't sell them, sharing my experiments is just my way of encouraging others to try DIY and better understand the cause and effect of how speedlight diffusers work. The materials are shown below, except for the roll of 2" wide velcro used for attaching.
The white mesh on the right is used for cross-stitch projects. I used it in my Mk1 design between the sheets of foam as a stiffener. I decided to use the full size placemat but it flopped over. To prevent that I first tried adding wires, but then got the idea to use the the strip mesh to hold it up. It's just stapled to the mat on top and wraps around the flash to form a tunnel. Here's how it looks lying flat:
Here's a comparison with my "Mark2" design. It is made out of a plastic cutting board sheet:
It was simpler to construct than the earlier foam design but I wasn't able to find white cutting sheets at the time and had to paint translucent ones. The paint has started flake off, which is why I had my eye out for new material.
Here's a comparison with the "Mark1" design made out of "fun foam" and the earlier "Mark0" design out of mat board I created around 10 years ago:
In 2003 when I started making the DIY diffusers had been shooting for nearly 30 years with a pair of Vivitars using a bracket and off camera flash without any diffusers and getting results I considered acceptable for candid speedlight shots. I only started experimenting with diffusers I created out of mat board and tape because I thought they were pretty worthless and someone on another form posted a template from a popular commercial model which made it easy to copy out of mat board. I wanted to see what the differences were vs. my baseline of direct flash. I discovered not much if compared outdoors at night, which is what I suspected and why I never spent $20 on a commercial diffuser.
The reason there wasn't a lot of difference in my results was because the diffuser didn't make the source much bigger and using a bracket I didn't see many shadows on the faces with direct flash. If you don't see any shadows there's no compelling need to make the shadows lighter and the edges fuzzier is there? That's why I suggest those wanting to improve single flash shots to buy a bracket.
The main benefit I saw vs. direct flash came indoors from the fact the flash tilted 45 degrees bounced more light off the ceiling than directly changing the modeling vector from eye level to downward and natural. But I was already getting that modeling vector with the bracket and compared to just bouncing the only benefit of the small diffuser was putting catchlights in the eyes a bounce shot lacks.
Since ceiling bounce isn't efficient and because I use two flashes in a OCF key over bracket-centered fill configuration I modified the commercial clone to make it more "bowl" shaped and bounce more light forward, winding up after several prototypes with the Mark0 mat board creation above.
What is different in concept from caps and scoops designed for single flash is that I wanted most of the light bounced forward, which is more efficient. I didn't need ceiling bounce for modeling, I had the bracket for that.
Since day one using flash I've always created a downward modeling angle in single flash shots with a bracket, and with dual flash shots by placing the OCF above the heads of the subjects. One of the benefits of adding the diffuser to the flash on the bracket was that with the flash head aimed straight the center of the diffuser was about 6" higher and created more natural modeling than the direct flash on the bracket.
I shared my early experiments on another forum and a guy seeing my Mark0 design created one using "fun foam" sheets, a material I'd never seen before. It solved the problem of storage by folding flat. But when I tried it I found the foam was too flexible and the "scoop" too tall and narrow. I solved that problem by putting the plastic mesh used for cross-stitch projects between the two sheets of foam. A also made the top flap bigger and folded it down more to more light went forward vs. up.
Folding top flap fold over to cover the flash head produced a pattern more like a soft box, but I also had the option to open it and bounce most light off the ceiling creating results similar to a StoFen when a ceiling was available .
But I found that with the top of diffusers on the bracket a foot or less from an 8' ceiling the footprint overlapped and created "spill fill off the ceiling and walls. What I got with my mostly forward design was a direct "key" vector that modeled the face directly from the diffuser like a soft box does and "wrap-around" fill from the spill. That's illustrated in this single flash shot with a bracket and foam diffuser:
It's easier to see the "key" vector pattern created with the direct light from the diffuser when it is blurred:
That "mask" of highlights created by the downward angle of the light is how our brains recognize the 3D shape of the face. The more the dominant vector of the flash modeling matches angle of natural light the more "normal" the flash lighting looks on the face. That's why I advise people the best investment for making single flash shots more flattering isn't a diffuser it's a $50 Stroboframe camera flip bracket to get the flash above the head of their subjects.
What is also important to understand when using speedlight diffusers is that the apparent "softness" in the lighting isn't going to come from "wrapping" the key light unless you want to drag around a big umbrella. If you want to stay mobile you should learn how to create that downward modeling vector AND a lot of spill fill at the same time with one flash. If you do use that big umbrella what will create the light shadows on the far side of the face opposite it? Not wrap. The big ass umbrella will spill 10x more light around the room than any of the diffusers pictured here. That's good, but not practical for "run and gun" PJ style shooting.
Here are some shots which illustrate the cause and effect of using a bracket with single flash and what happens when it is used as fill with an OCF "key" light to the side. Friends stopped by with their 4 year-old who was usually a fussy and whiny. But that day she was wearing her nice dance outfit and acting like a diva. Having one the camera and single flash on the bracket w. foam diffuser handy I put her in a white chair and grabbed these two quick snaps:
They show the cause and effect of using the bracket. Raising the flash straight up hides most of the shadows and those that are seen like under the chin in the first shot while dark are naturally places and not really noticed much. The contrast of the shadow under the chin helps to reveal it's shape. It's just not very flattering because it's unfilled and too dark even with the "spill fill" bouncing off the light walls and the chair. There wasn't much ceiling bounce because it's 12' in that room In the second close-up I was so close and the flash so high relative to the face the upper lip is shading the teeth but the angle hides the dark shadow the chin was also casting.
Seeing she was in a mood to cooperate I ran and grabbed the slave flash on the stand and flipped the switch on the 580ex in the bracket to Master and dialed in a A:B =1:1 ratio. That's equal INCIDENT key (B) and fill (A):
Same modifers at a similar distance with the same "spill fill" factor. Why does the lighting look "softer" preceptually? Not because the key modifier is wrapping the face but because now the flash on the bracket is acting as fill and eliminating the dark unflattering unfilled shadows.
I know this defies conventional wisdom that you need a big key light modifier to get "soft" light, but consider that in the 40's everyone used direct fresnel lighting for stills and movies and the lighting was made to look very soft, or hard with those same direct sources. How? Those guys understood how to use fill. So did the guy who taught me to use flash 40 years ago because he started with flash bulbs in a small reflector on Speed Graphic and direct studio lighting.
Perceptually "flat" light and "soft" light have the same shadow clues (very subtle). This shot with a single flash on bracket with diffuser had very little "spill fill" because the ceiling was high and dark.
It doesn't look "hard" because the vector of the light isn't very high and creating any unfilled hard shadows you see in the foreground.
What did the diffuser add to that shot over direct flash on a bracket? The flash is a bit higher and the slightly larger size created larger more appealing catchlight refections and larger less specular reflections off the skin. The specularity that is seen doesn't look odd as in a hot shoe mounted flash in portrait mode because raising the source on the bracket + diffuser moves the reflections up on the cheekbones to were natural light puts them when it models the face. Where the highlights fall on the the face are also clue the brain using to discern 3D shape in a photo. Absent many shadows as in the shot above the placement of the highlights on the face are the primary clue the brain uses to determine 3D shape in a 2D photographic rendering.
The take away here is to realize any small speedlight modifer alone is not going to put the highlight clues in the "right" (i.e., natural looking places) on a face unless it is also raised above the face. The small diffuser also isn't going to create "wrap" directly. The "wrapping" which makes the shadows lighter and softer looking comes from all the indirect "spill fill" vectors off the walls and ceiling from the parts of the light's footprint that isn't hitting directly. The modifier splits one source into a dominant "key" vector and lots of different "fill" vectors hitting the shadows from different directions because part of the footprint hits ceiling and walls.
A gradient from highlight to shadow is created by light from the source falling off with distance. If you aim a "flat" eye level flash at a face the nose will be lighter than the ears not because the light "wraps" but because it falls of in intensity front>back on across the side of the head. If the flash is moved closer to the nose with the same modifier the gradient gets steeper because it falls off nose> ears at a greater rate. Went exposure is adjusted to keep the highlights on the nose the same the shadows will appear darker than before. What will make those shadows lighter and the overall gradient more gradual is when fill from a different direction reaches the ears. To do that it need to come from a different direction, which is why bouncing light around the room with a speedlight modifier is a good thing. But so is controlling that cause and effect.
StoFen and Lightsphere are excellent at creating soft lighting in a small indoor room. So soft in can make a normal room look as flat and 2D as an overcast day outdoors. That's soft lighting but is it always the look you want in a photo?
The reason I use two flashes isn't to get more light it's to control where the light comes from and the apparent softness via the lighting ratio. That's what I learned from Zucker many years ago. Put a direct flash 45 degrees to the side and 45 degrees above the eye line on a face and it will be natural, as natural as a face in direct sun at 2PM. To make the lighting with direct flash natural and FLATTERING requires fill to lighten the dark shadows which aren't unflattering because they are poorly placed but because they are simply dark.
Progressively add fill from the camera and the shadows get lighter and perceptually it looks "softer" because the overall highlight:shadow gradient isn't as steep. The fill falling off from nose > ears creates it's own gradient over the cheeks via front > back, nose> ear fall off. The shadow on the nose will be lighter than the ear further from the fill source, if the fill source is over the camera closer to the nose.
Why don't more photographers understand that? Most wouldn't think to put fill anywhere near the camera because they never saw good results with a flash placed there. They probably never used a flash bracket either.
With a diffuser on single flash with a diffuser on the camera hot shoe most of the spill fill comes from the direction of the camera because that's where the light source creating the spill is. If you walked behind the subject you'd see spill fill on the back of the head too from the back wall, but not as much, unless your subject is 6" from the wall like my co-worker Ray was in the shot above. The cause and effect of using the flash on bracket as will when a second is used off camera is similar.
What I get when using two flashes is the ability to move my key light off axis to create more shadow modeling while having even more control of the fill and shadows than when bounce one. As much or more light is bouncing off the walls and ceiling as spill fill but I can control the direct front> back gradient of the fill on the face with the power and distance of my flash on the bracket.
The diffusers? They have less to do with the results than the fact the key light vector models in a naturally flattering way and the fill strategies, direct and bounced, keep the shadows the key light vectors don't hit light in tone.
What's the difference between my Mark0 to Mark 3 designs? In terms of cause and effect not much. When one flash is used all the softening effect seen in the shadows comes from the spill fill with all of them. What the bigger sizes does is create a bigger footprint, which creates more spill fill indoors. Outdoors? The bigger size will just create bigger catchlights with little little change seen in the shadows because there will be no spill fill.
I switched from Mk0 to Mk1 for logistics - being able to fold it flat and stick it on my bag. I tried the foam and it worked better but doesn't hold up well.
I switched from Mk1 to Mk2 because my Mk1's were worn out and the plastic sheets were lighter and simpler to construct (once painted) and not as fragile. But the larger size is less practical. They don't fit in my shoulder bag.
I've switched to the Mk3 design to eliminate the painting step, but had to add the mesh because the table mats are not as stiff. It remains to be seen if I stick with them or go back to the Mk2. I also use still the Mk1 design because they fit into my camera bag on top of the camera and lenses.
How did I find out which works best and which is most practical? By experimenting with different designs, what I encourage everyone to try by posting threads like this