- Equipment and Setup
- Green Screen Backdrop
- Lighting the green screen
- Angle the screen
- Camera and Tripod
- Camera Settings
- Exposure Settings
- Subject and Green Screen Placement
- Lighting the Subject
- Replicate lighting conditions
- Green Screen Tips and Considerations
- Green or Blue screen?
- Subject clothes matter
- Avoiding seams on your green screen
- Additional benefits of using key
- What to do if you do not have a green screen?
Green screens have been instrumental in creating visual marvels in both photography and movies for decades. With basic tools and techniques, photographers can transport their subjects from a simple green backdrop in their garage to virtually any imaginable scene.
While filmmakers primarily use green screens to create various visual effects and transport scenes to otherworldly places, their relevance in photography might not be immediately apparent. However, the benefits are noteworthy.
Consider the logistics involved in setting up a scene for photography: packing and unpacking gear, ensuring perfect lighting, and arranging specific assets for each scene location. It's a meticulous and time-consuming process. The green screen in photography is a game-changer.
Photographing against a green screen allows for effortless background replacement in post-production. This streamlined approach saves time, simplifying the entire process. But before we replace backgrounds, setting up and lighting the green screen correctly is crucial to achieve the desired illusion. Today we cover the subject and answer the question of how to use a green screen in photography starting from setting it up to giving you bonus tips.
Equipment and Setup
So, if you fancy adding a little bit of Hollywood into your photography just with a simple little green screen to change some plain and boring backgrounds, you need to understand how to set it up properly. For that we need the green screen backdrop, the stand for it to mount, and the lighting for the model (subject) and the screen itself. Additionally, you want to have a tripod for your camera but that is an optional choice.
Green Screen Backdrop
The most important thing is the actual green screen itself. You can get a professional chroma key green screen from just about any film equipment vendor.
Green screens can be made from most materials and the common one is a thick cloth. We want it to be thick so the light does not go through it or change the color luminance value. However, it could be a cardboard material as well as any solid surface. Hence, you can simply paint a wall to serve as a green screen.
While setting up the green screen canvas, we need to make sure it is stretched enough and not crumbled in its areas because these seams may cast shadows from your lighting. If your green screen is not cut and stretched and you are working with the original canvas, use clothespins or other improvised means to secure it to the stand. Professional green screens will be more likely durable and designed with grommets or other features that make them more practical and easier to set up.
Lighting the green screen
The lighting technique is the same for all the mentioned types of screens. Essentially, we want to have at least 3 lights: two lights to put on either side of the green screen backdrop and at least one light for your subject. The more lights the better results but the light separation from subject to backdrop is the key. Hence you can add a fill or hair light as well to your setup.
Whatever light you use, make sure that it is soft and big because it affects the smoothness, helps to avoid gradients, and covers the whole green screen. Lights with the softbox is a common use for green screens. No matter how many lights you use, make sure they all have the same colour temperature to blend naturally on the screen.
Ensuring that your screen is consistently 2 stops of light darker than your subject is crucial for an easier keying process. Additionally, it's essential to steer clear of hot spots on the screen, as these spots of intense light can lead to variations in the green tint, resulting in visible seams. To achieve a smooth and even distribution of light across the screen, position your lighting carefully, using diffusers when possible. This method helps in spreading the light uniformly, mitigating the appearance of shadows, and minimizing the formation of 'HotSpots' that can impact the seamless background effect.
Angle the screen
Slanting the green screen slightly towards the ground is a smart strategy to minimize spillage on your subject and improve light distribution across the screen. This setup can significantly reduce unwanted reflections or light bouncing off the green screen onto your subject, leading to cleaner and more consistent keying.
Camera and Tripod
For an optimal experience, utilizing cameras with APS-C type sensors or configuring your Full-frame camera to record only APS-C mode while using a full-frame lens is advised. Why? Because with other lenses, even under good lighting conditions, they tend to cast a vignette effect over the perfectly lit green screens. This results in a more aggressive post-production keying, potentially affecting parts of the image. However, APS-C sensors bypass this issue, requiring only a step back from the subject to maintain framing. One downside is that smaller sensors may generate more noise, but this doesn't offset the vignetting factor. To counter noise, we recommend using 4K resolution cameras, preserving more details in the shot. If a 4K camera isn't available, shooting in portrait mode can nearly double the pixel density for FullHD formats compared to landscape shots, albeit with framing limitations.
As we mentioned earlier, the camera tripod is an option, however, you would have a much easier experience by having one in your setup. The more about the tripod we cover in the camera settings paragraph for shutter speed as these have co-relations.
The best results shooting on a green screen could be achieved while shooting at focal lengths of 35-55 mm. But if you decided to shoot on a full-frame camera instead of APS-C, then this setting shifts to 50-85 mm.
1st we want to set our camera to manual exposure but adjust the ruler on top of the camera body. Otherwise, the camera will constantly change the brightness level which is harmful for all of our lighting setups including the green screen. For the same reason, we set white balance to manual as well in the settings. Setting the white balance to the ‘Day Light’ preset or equal to that usually works great unless you want to make a sunset effect.
Shutter speed - 1/100 sec is the quick answer. The faster the shutter speed the less green screen spill we get in the shot. For that very reason, we want to have a tripod to avoid any blurring in the frame caused by a simple shutter button press on taking the shot.
Aperture - Even the brightest lights are nowhere near as bright as sunlight outdoors. So you want to set the aperture to a rather low but not extremely low number. F/5.6 usually works great.
ISO - is our only real variable for the exposure settings. We want to set it to a value that gives us a decent well-lit image. That obviously depends on the light you used in the end. Brighter lights will let you choose a lower ISO than not-so-bright lights. But when deciding on the lights, always keep in mind that bright lights glare the subject. It is really hard to look into the camera when the lights are glaring. Start with an ISO of 800 and see how it looks then adjust it in accordance with your lighting setup. If you are concerned about the light difference on your screen and the subject and their correlation with ISO, you can always use the light power management to adjust and balance with your camera settings.
If we are going to move around the room with our camera we want it to have good autofocus and ideally face detection. For that, you can use some Sony a7III budget option or a7IV or an equivalent and you won’t have any issues shooting on a green screen in terms of focus.
Avoid conducting a focus pull in front of a green screen as it might complicate the keying process. To maintain ease in keying, opt for shooting with a closed aperture that ensures everything is in focus. If necessary, you can introduce the focus pull effect during post-production by applying the camera lens blur effect
Subject and Green Screen Placement
The key reason for keeping distance in mind is to prevent green screen spillage, which might cause a noticeable demarcation between your subject and the backdrop. Typically, it's advisable to position the talent or subject approximately 10 feet away from the screen, although in scenarios requiring close-up photography, a shorter distance may be more appropriate. Keep in mind that the proportion of the green screen and the subject in the frame should correspond to the future background replacement. The greater the distance between you and the subject, the more green screen you'll capture. So, if you aim to create an illusion of distance between the subject and the background, a large green screen canvas and sufficient room to set it up might be necessary.
Lighting the Subject
Divide your lighting setup into separate zones for the green screen and the subject. This division ensures better control over both areas and prevents light spillage between zones. Consider using a Cinefoil or a flag to delineate the lights into distinct zones, if needed.
When illuminating your subject, aim to match the lighting to the background you intend to use. For instance, if the background has a vibrant orange backlight, try replicating a similar effect on your subject. Failure to do so may result in an unconvincing match between the subject and the background.
Replicate lighting conditions
If you plan to replicate outdoor lighting effects in the background during post-production, consider shooting the green screen outdoors under the same lighting conditions. This method saves time in post by aligning the angles and lighting consistency between the subject and the background. Matching a sunny day's lighting with a cloudy one in post-production can be challenging, so capturing the green screen outdoors can be beneficial.
Green Screen Tips and Considerations
Green screens are more prevalent in movies than in photography, mainly due to two primary reasons. Firstly, working with green screens typically requires a solid understanding of Photoshop or other editing software. It demands confidence and expertise in post-processing to effectively use green screens for background compositing.
Secondly, some photographers steer clear of using Photoshop to composite backgrounds as they believe it detracts from the authentic ambiance of an image. Photography is often perceived as a pure art form, capturing moments authentically. Using green screens and extensive editing might compromise this authenticity by creating a perceived gap between reality and the final image.
However, for beginners in photography or those exploring surreal or conceptual art styles but lacking expertise in Photoshop, green screens offer an intriguing avenue. They serve as a gateway to creating fantastical and imaginative compositions. By utilizing green screens, photographers can transform a beautiful picture into something truly spectacular, enabling the creation of visually stunning art. So here we present tips on some non-obvious screen usage that will help you to improve quality and make it easier for post-production as well.
Green or Blue screen?
The key difference between green and blue screens lies in their suitability for different lighting conditions and specific visual elements. Both colors serve as excellent choices for chroma keying due to their distance from skin tones, but each holds distinct advantages.
Green screens tend to excel in bright scenes. They offer better results when the lighting conditions are well-lit or when the scene is predominantly bright. On the contrary, blue screens perform better in darker scenes or environments and are particularly effective with subjects having blonde hair. This variance in effectiveness is attributed to the luminance properties inherent in both colors.
From a digital camera's perspective, the sensor captures images based on various red, green, and blue pixel values, which amalgamate to form the colors you see. When capturing a portrait, skin tones are composed of red pixels, manifesting as pinks, darker reds, or varying hues based on the individual's skin tone. Interestingly, green is notably absent from skin tone composition, being the complementary color to red on the color wheel. The same principles governing skin tone colors apply to blue screen backgrounds, just as effectively as they do to green screens.
The cardinal rule when choosing your screen color is to ensure that the background color does not appear in any form within your foreground subject. This ensures a clear distinction between the subject and the background, making it easier to isolate and manipulate during post-production
Subject clothes matter
Clothing choice is a crucial consideration when using a green screen. People generally tend to wear more blue-colored clothes than green, making the green screen a more feasible choice for keying. However, wearing black clothing doesn't necessarily simplify the green key process; it can often result in green spills or reflections on the black garments, complicating post-production work.
Moreover, it's advisable to avoid wearing anything shiny or loosely hanging, such as a belt, as these elements can create challenges during post-production editing. These factors can affect the quality and ease of editing when using a green screen setup.
Avoiding seams on your green screen
The setup of the green screen is crucial for a successful keying process. Eliminating wrinkles from the green screen is essential as they can significantly complicate the keying procedure. Ironing or steaming the green screen can effectively smoothen it out, ensuring a seamless background for easier editing.
Additionally, ensuring the green screen is set up as tightly as possible serves the same purpose as ironing or steaming. A taut setup helps maintain a smooth surface, minimizing any imperfections that might interfere with the keying process.
Additional benefits of using key
The green screen technique isn't just about switching backgrounds; it also streamlines the post-processing method to remove objects from photos. Establishing two separate layers, avoiding light spillage, ensures a consistent environment that minimizes lighting inconsistencies. This cohesion significantly aids the precision of Photoshop's tools in isolating and removing specific elements within the photo, ensuring a more accurate and efficient removal of unwanted objects
What to do if you do not have a green screen?
Using RGB lights can indeed replicate similar functions in lighting setups for green screens. Additionally, incorporating green lighting specifically for the screen can enhance its color consistency and make it more even, providing a better chroma key effect. The key is to ensure that the lighting across the screen is uniform and well-balanced to achieve optimal results.