Sunday, July 12, 2020

Diffusing a Macro Twin Flash

I've probably spent the better part of a decade trying to wrap my head around flash photography and how to diffuse a harsh point source like a twin flash in as short of a space as possible. For field macro you just don't have a lot of room to work, so any diffusion scheme has to be compact. I also like to use a twin flash as two separate light sources, in a key (one head at the top of the lens) and fill (one head off to the side) configuration because it gives me a lot of control over the highlights and shadows. It also allow me to partially wrap light around the subject so that it doesn't look flat. If you place the flash heads on opposite sides of the subject, or fire them through a single diffuser that's connected to the end of the lens, the light will be too even across the subject and will potentially make the subject look flat. I don't focus stack, but for those of you who do flat light is a composition buzz kill. Get everything in focus and evenly lit and your images will look 2D. So here's what I've learned while loosing my mind trying to diffuse a twin flash:
  • The diffusers that Sto-Fen sells, and the set that Cannon supplies with the MT26EX RT, are better at blocking the light than they are at forcing it to spread out. You'll lose about a stop of light with either of them for a very small gain in diffusion and I think the same can be said for just about every hard diffusion plastic. I'm not going to do a "how to" on this one cause I don't want you to blame me if you ruin the diffuser set that comes with your MT26EX RT. I bought a second set from Canon to test out my theory that they weren't really diffusing the light very well, and as soon as I got them I used a Dremel tool to remove the front diffusion plastic so I could use it as a base for my own design (I just needed the frame and the clips that hold it to the flash heads). Due to some shipping issues I ended up paying over 60 USD for the set, but it was worth it cause I was right. If you follow me down this rabbit hole with the only set of diffusers that you have for your MT26EX RT you do so at your own risk...
  • 1/4 stop white China silk is the only material I've found that can force the hot spot in the MT24EX (and to a greater extent the MT26EX RT because it has a better built in diffuser) to spread out. It's best to use two layers separated by an air gap, preferably with at least a centimeter between them. Putting one layer of silk directly over another will cause the light to drop by at least a stop, so separate them. You can get it at B&H Photo but it's a little pricey and they have to special order it. I've been looking for a better, cheaper source. Note: The MT24EX knock off flash units perform about the same as the MT24EX, so 1/4 stop silk should also work for them but I have no experience with those flashes. At some point I'm going to experiment with other materials because I'd like to find a cheaper material than silk and not all diffusion surfaces are the same. Each of them diffuses the light in a different way.
  • Gary Fong's Puffer Plus makes an excellent last diffusion stage, if your trying to keep the size of your diffusers as small as possible, because the light transmittal is good and the surface is dimpled (it acts like a much larger diffusion surface). I've been looking for a similar photographic grade material that's not curved, but so far no joy. I've experimented with a lot of different diffusion plastics for that last diffusion stage and none of them performed better than the Puffer Plus. Even just using another layer of 1/4 stop white China silk didn't work as well.
Here's where things get "tricky": There's a difference between soft light and diffused light, and they are not the same. Using a diffuser that is large relative to the subject will give you soft light, and you can see it in the quality of the shadows. But diffusing the light means forcing the light to spread out, and a large diffusion surface relative to the subject won't necessarily do that. Diffused light means forcing the light to spread out so that the intensity of the light across the diffusion surface is the same. You can have soft light (soft shadows) and a hard well defined specular area. This video explains the difference between soft/hard light and specular/diffused light better than I can.

Understanding the difference between soft and diffused light was a eureka moment for me, because I initially thought that I had hit a hard limit in my diffusion because using a larger diffuser wasn't practical. But my light was soft enough with my current diffusers, or another way of saying it is that my diffusers were large enough relative to the subject, because I was getting soft shadows. Take a look at the shadow under the Sourgrass petal just below the Sweat Bee's antenna:

Sweat Bee in a Sourgrass Flower VI

The shadow is soft, so my diffusers are large enough. But the light that they were creating could best be described as "soft specular" and not "soft diffused" because the specular area is still well defined and almost harsh. My light wasn't really diffused. But after modifying the internal structure of my original diffuser (the details of which I'm not going into) I'm now getting soft diffused light with almost no hot specular highlights (the intensity of the light across my diffusers is almost the same) while only losing about 1 and 1/4 stops when compared to the bare flash heads. Light that's so well diffused I'm having a tough time determining if I've nailed critical focus on a some subjects, when viewing images on my camera's LCD screen, because there is no noticeable specular reflection in their eyes.

Foraging Cricket II

The Death of the Kaiser

After some experimenting with a cooperative, and very metallic, Chafer Beetle I've determined that using a Kaiser Adjustable Flash Shoe to elevate the key is working against me in most situations. Depending on the angle that I'm shooting from it can cause the fill light to be too harsh and/or pump a lot of light into the flower that a critter is perched on creating a third specular highlight. So I'm going to be shooting with both flash heads on the Canon flash mount and use the Kaiser for special situations where it will work to my advantage.

The quality of your light and the angle between the light, subject, and sensor will determine how much detail you can capture. You can easily lose more detail to poor light quality than to diffraction, and if you focus stack you really should be putting some serious effort into your light. Doesn't make sense to spend all that time to create a stack only to blow out detail with poor specular highlights and a lot of micro contrast (reflective areas throughout a scene where the detail is lost due to harsh light).

Note: All of my diffuser design has been geared toward creating a relatively small, compact, diffuser that would give me the light quality that I wanted but still be practical for field macro. However light is light, and I'm sure that the information I've provided in this post can be applied to any diffusion setup that you might build for yourself.

Sunday, June 14, 2020

Monday, June 8, 2020

Ladybug 3D Microscope

Mr. Ahron Wayne contacted me via my Extreme Macro Facebook page to tell me about a Kickstarter project that he and a team of engineering students have been working on. It's a motorized scanning macro camera:

I wasn't all that excited, because I shoot single frames of active subjects, until I saw it track a moving critter in the video! Pretty cool :)

This isn't a paid add, or an endorsement of the Kickstarter campaign, I just thought it was a really interesting project and I know a lot of you are going to be interested in it as well :)

Friday, June 5, 2020

Sweat Bees in Sourgrass Flowers Deconstruction

Sweat Bee Foraging in a Sourgrass Flower III
I want to give you a full breakdown of how I'm shooting active Sweat Bees, and most of what I'm going to cover will apply to just about any active subject. The image to the right was what I was trying to capture, although it's not the frame that's still stuck in my head. I can't control where the critter is going to be, or where the antennas are pointing, so I just have to work with what she gives me. But it's close and I'm happy with it, and here's how I took it.

Sourgrass starts growing in my yard in the fall and by early May it's already dormant and waiting for cooler temps and less sunlight. It typically blooms in the early spring, so the peak time for the flowers to be in full bloom is from about mid February to mid April. Most of the ground dwelling bees don't get active until late March. So there is a roughly four week window to photograph female Sweat Bees foraging in Sourgrass flowers for pollen. After the Sourgrass is gone they move on to other pollen sources (like Dandelions). The flowers completely close in the afternoon and don't open until the sun has been up for a few hours and it's already warm. So there's no chance to catch a sleeping bee in one of them unless it rains after the bees get active and there is a temperature drop. So shooting the critters when they are hyperactive and foraging for pollen is the only choice, and it's what I'm looking to capture with the camera anyway.

A lot of people will tell you that you cannot shoot macro on windy days, but it's actually not true. Most insects are very sensitive to vibration, and it's easier to photograph them in flowers when I can grab onto the flower's stem with my left hand and then rest the lens on that same hand to keep the scene steady. But when it not windy it's easy for the critter to tell when I've grabbed on, and when they do they'll stop foraging and come to the top of the flower to investigate. More often that not they will be facing away from the camera, but it's not a total loss since I'm holding onto the stem and can gently rotate the flower so that the bee is facing the camera. This is the type of shot that I can get when she figures out that I'm close.

Sweat Bee in a Sourgrass Flower VI

Not a bad shot, just not what I'm looking for. To get the depth that you see in that image I'm focusing on the leading edge of bee's mandibles, using my peripheral vision to frame and compose the scene (so I don't have to look away from the focus point), and twisting my wrist (sometimes both of them) to lay the area of acceptable focus over the curve of the critter's head. In that scene I'm tilting the frame toward the top and right without moving the focus that I have on the bee's mandibles, and it's something that I don't have to think about after 14 years of shooting macro (13 of that with just the MP-E 65mm macro lens). I then refocus, reframe, and take another shot if the subject doesn't take off and I can take each shot with less than a second between them because all I have to think about and concentrate on is where I'm placing the initial focus. I'm not shotgunning the shutter release and hoping that I get something to post, and since the bees are in motion if a "spray and pray" technique gave me a usable image it would just be pure luck and that's not how I want to shoot anything. Being able to rapidly reframe, refocus, and take a shot is important because they are in motion and I want to catch them stripping pollen out of Sourgrass anthers with their mandibles like this:

Sweat Bee Foraging in a Sourgrass Flower

Still not the frame that's stuck in my head, but I'll get another opportunity to photograph them again but it won't be until next year.

Note: There are still a lot of you out there who think that all you need is the equipment that I have and images are just gonna magically jump into the camera. Someone recently replied to one of my posts on Reddit indicating that he wished he had my gear, to which I replied that what he really wanted was my 14 years of experience shooting macro. This is what he said:

"You don't know me or my want to..... so you may be right but.... I could give you a run for your money with an 8th of the experience!! just give me a camera equally powerful promise il deliver lol"

I asked for a link to his gallery and didn't get it, and rightfully so. If he could give me a run for my money with my gear and 1/8 of my experience then he should be shooting at my level already because the equipment I use just makes my style of shooting convenient for me (might not work for you). Notice that in the deconstruction above not once did I mention the hardware I used, and I didn't mention it cause it wasn't relevant to getting the photos. Everything depended on my knowledge of the subject, my ability to get close to an active wild animal, and how to make the most out of the limited depth of field.

That next lens, next camera body, next whatever isn't going to make you a better photographer. Learn to use what you have now...

Tuesday, May 26, 2020

The Dreaded Error 01

I'm back to shooting with the Canon EF-S 60mm + extension tubes because my MP-E 65mm macro has broken again (3rd time). The aperture makes the most God awful crunching sound when I take a shot, and the display reads Error 01 and tells me that there's something wrong with the lens contacts. It's a generic error that pops up when the camera cannot communicate with the lens, and from experience I know it's because the cable that runs between the electrical contacts and the aperture assembly has worn out. I told myself the last time it broke that I was just gonna use the EF-S 60mm and tubes or buy a new MP-E. So I think I'll use the EF-S lens for a while until I decide what to do. Knowing my luck I'll buy a new one and Canon will announce a version for an RF mount...

Which brings me to the last topic I want to mention: I'm feeling the need to shoot full frame but I'm not sure about getting a mirror-less camera. I photograph a lot of semi-active to hyperactive subjects and I'm concerned that the display lag between the sensor and an electronic view finder (EVF) will be an issue. For those of you shooting with a Canon mirror-less rig how's the EVF lag?

Friday, May 22, 2020

Bumblebes Foraging in Grape Hyacinth

One of the followers of my Extreme Macro Facebook Page posted a link to a video that he shot that I just had to share. Methias Solstrand did an excellent job of filming Bumblebees in motion foraging on Grape Hyacinth flowers. I always associated pollination with the hairs on bees, but these Bumblebees are clearly pollinating the flowers with their proboscis.