It’s been quite awhile since I posted to my blog. It was a great Summer and Fall, but Winter is dragging on. But that also means I now have time indoors to try some Green Screen techniques. My setup is actually optimized for video; my lights are all continuous fluorescent. This actually cases problems for portraits, as I will explain later.
I’m a big fan of a certain television series filmed in my home city of Albuquerque , New Mexico, and I needed a new headshot for my Facebook page. So I decided to take a self portrait, and transform myself into “Hines”+”enberg” = “Hinesenberg!”
[The character in the show is Heisenberg; named after the famous physicist who was one of the leading developers of Quantum Mechanics.]
This gave me an excuse to learn about green screens…
The image below shows my setup for the shot. The main lighting and backdrop are from “video” kit from Linco lighting. The kit is inexpensive, but the quality is surprisingly good. The total wattage is only 1500, but provides enough light for most amateur video applications, and still photography (but, again, causes issues for portraits). The kit comes with three octagonal reflectors that can be covered with diffusing material to convert them into softboxes. The octagons also have tension cords around their perimeters that allow the exit aperture to be reduced, even enough to form a “snoot.” This is great for concentrating light into a confined beam and directing light where you want it.
I used two of the softboxes to uniformly illuminate the green screen background. This is very important, since any lighting gradients make “knocking out” the background much more difficult. It’s also important to make the background cloth smooth and wrinkle-free; again, wrinkles will cast shadows that will be hard to knock out in post.
I have some cheap, clamp-reflector lamps from the hardware store mounted low on the stands that I use to illuminate the bottom of the green screen for standing shots; I didn’t use them for this session.
I wanted illumination all over, with some interesting shadows as well. So, to illuminate my face, I used my cheap umbrella diffuser on one side and a 5-in-1 reflector (with its silver surface) on the other. The 5-in-1 reflector was supported by a reflector boom connected to a mic stand. I also mounted a speedlight on my camera with a soft box attachment to provide front fill lighting. I had the flash on 1/8 power so that the key lighting was from the umbrella, and the flash just removed harsh shadows.
I used my 50 mm prime focus lens to get a sharp focus, but short Depth of Field/Focus (DoF); this was to make sure that any remaining wrinkles on the backdrop were out of focus.
Because I wanted short DoF, I used f/4.5, but this also meant I needed to focus on a subject with the correct height and distance from the camera. I used a small tripod to hold my jacket, sunglasses and hat (see image above), then focused on these. I also took several test shots with aperture priority and different flash settings to get a good exposure. I had a remote control to trigger the camera from my seated position in front of the camera, and took about 20 shots. It turned out that light from the windows in my living room caused troublesome reflections on my sunglasses, so I reoriented my pose and shot twenty more.
This is where I learned an important lesson. I was using a wide aperture and ISO 200. This meant the shutter speeds were moderate, about 1/60 to 1/100 seconds. This was slow enough that the images were blurred a bit by my motions. No matter how hard I tried to stay still, all of the images were slightly blurred.
In the future, there are three modifications that can address this. Brighter continuous lights would enable shorter exposure, freezing the action better. I could have used a higher ISO setting, especially since I was making a Facebook portrait that would not be affected by some added noise. However, the best solution would be to get a couple of strobes for the softboxes. The flash would freeze the image regardless of the shutter speed (within the sync range). That is what the pros do, and is clearly the best solution… Fortunately, my birthday isn’t too far off!
I next loaded the RAW image into Photoshop using the Adobe Camera Raw plugin. From there, the rest is just standard post-processing manipulation using layers. The RAW image as shot is shown below. The colors are not correct, but that’s the great thing about RAW; there is much more information in the file that is easily displayed. This enables lots of head-room to make color corrections.
Note that the background is uniform, with no shadows or wrinkles. The backlight over my should helps give definition against the green background. Also note that I avoided any color on my wardrobe that had any green or blue hues. This also helps in knock out later.
The image above shows the results after color-correction, background knockout, and a tight crop. The crop was not planned, but I had to crop it that way to crop out the top of the chair. I’d also planned a more rectangular, “portrait” crop. But again, the square crop made a better composition. In hindsight, these crops make for a much better composition.
I also had to do a bit of refining on the right side of my face and hat, because there was a bit of green reflection from the green screen. I knew this would be a problem, since I was too close to the green screen; only about three feet. It would have been better to be about five feet from the screen.
Next I found a free wallpaper image of green smoke made to look like the opening credits from the show, dropped it into a background layer. The image is very sharply focused, and makes the blurring of my portrait more noticeable. I tried to blur the background a bit, but that made it less obvious that the image was green smoke filaments… It just didn’t look right.
So in the end, I just used the smoke image with full detail. I did adjust the levels of the smoke image a bit before compositing the background with my portrait.
The image above shows the final product. You can see that the softness on me is caused by motion blur, rather than focus, because the blurred regions are located at a range of distances from the camera.
Aside from my double-chin (and the slight motion blur), the final result turned out pretty well. I think this is an appropriate homage to my favorite show… And a proper celebration of being 51 years on planet Earth!
[I have a special shot planned for my 52nd birthday… heh!]
I hope you found this useful, or at least entertaining.
Sharp focus and happy shooting.