FEBRUARY 26, 2021
Learn how a variable depth of field is used as a cinematic tool. Oliver Janesh Christiansen discusses deep focus cinematography with
Erik Messerschmidt ASC and how the DP made use of the ‘Cinefade VariND’ to help control exposure as well as depth of field on ‘MANK‘.
Mank (2020) was beautifully shot by Erik Messerschmidt ASC in black and white, with scattered visual references to Citizen Kane (1941) - often cited as the best film ever made. The original cinematographer for Citizen Kane, Gregg Toland was incredibly influential, according to Messerschmidt. One of the most revolutionary things about Citizen Kane was Gregg Toland’s use of deep focus and Mank pays homage to this signature technique and introduces a novel storytelling tool - the Cinefade variable depth of field effect.
“There’s been a loss of using focus as a storytelling tool these days. You are always sharp on whoever is talking in modern cinema and I liked the idea of taking bespoke moments in the film and isolating characters with a variable depth of field. David [Fincher] had asked for a way to do this and it became a huge part of the film. I love the product, it’s great.”
- Erik Messerschmidt ASC
Oliver from Cinefade caught up with Erik to discuss his use of the VariND on Mank and his thought process behind some of the Cinefade scenes that feature a variable depth of field.
To achieve the 30’s Hollywood glamour look with modern digital cameras was not as simple as some might expect and Messerschmidt did a lot of camera and lens tests, as well as grading experimentation to get the look right. During these tests some of the choices he made were influenced by the way depth of field is affected.
“Citizen Kane was shot at very deep f-stops for deep focus. We aimed to do the same for most of the film. I looked at every spherical lens Panavision had, looking for the lenses that would give us the best results at deep focus, and believe it or not, we did end back on the Leicas, which we’d shot on Mindhunter. That was not my expectation at all, and it wasn’t David’s either. It’s just the way the math worked out.”
- Erik Messerschmidt ASC talking to Deadline
The Leitz (Leica) lenses are designed to be shot near wide open to be very fast lenses. In fact, most modern lenses are optimised between wide open and T4 but Messerschmidt wanted to shoot on the opposite end of the lens, which is rarely done in modern cinematography. When stopping down however, optical artefacts such as diffraction, spherical aberration etc. are introduced into the image - the lenses break down. He had anticipated that larger-format lenses, or some vintage lenses might therefore perform better, which they did in terms of resolution.
Large-format lenses however also result in a more shallow depth of field, as the iris is comparatively larger. The apparent depth of field on a large-format Primo 70 lens at T11 is less than on a Leitz Summilux-C at the same stop, something Messerschmidt himself learnt during the weeks of testing.
He also found Cooke lenses to be less precise in terms of aperture markings and when doing something as precise as the Cinefade, which uses the aperture markings during the lens mapping process, the German optical engineering of the Arri and Leitz lenses works to your benefit. He ended up settling on the Summilux-C lenses and generally stayed on the 21mm, the 25mm, the 35mm and the 50mm, which was also motivated a little bit from wanting to stay on focal lengths that were available at the time the movie is set.
Messerschmidt says that he doesn’t usually like shooting the Summilux at wide open because of slight aberrations, barrel distortion and optical vignetting. The centre of the lens gets sharper than the edges between a T2 and T1.4 and the bokeh becomes swirly. however, when testing the Cinefade and varying depth of field by 5-6 stops between wide open at a T1.4 and T11 he noticed that for moments of drama, this imperfection actually looks stunning.
The Cinefade VariND consists of two polarisers, one is motorised and the other static. Fincher is a very technical director and initially he was nervous about using polarisers because of possible reflection issues on cars for example. They tested it early on in the testing process and according to Messerschmidt, the Cinefade worked great right out of the box, so David realised he can do this.
Messerschmidt reveals that the Cinefade VariND “kind of lived on the camera” to help control exposure and maintain a consistent T-stop. One massive benefit over traditional ND filters is that the camera assistant can quickly and remotely change the neutral density, saving time and also giving greater flexibility and precision when setting exposure, especially when shooting outdoors on location.
Most of the movie is shot at around a f11 and they generally focussed the lens at hyperfocal distance to get the maximum depth of field in front and behind a particular focal distance. But sometimes they also used shallow depth of field. To help them decide between the two options, the Cinefade VariND often came in handy. In an interview with Filmmaker Magazine and Deadline he had the following to say:
“We debated whether or not we wanted the audience to see Welles at all until that final showdown with Mank. In the end, David decided that the audience had to see him. In the hospital scene where he’s walking down the hallway in that cloak, we looked at it in deep focus and then, I don’t remember whose idea it was, but somebody said, ‘Should we look at it at a T2?’ So I put four stops of ND in the camera and took another look at it. That was actually a game-time decision.
We used this tool called the cmotion Cinefade. It’s a motorized polarizer [ND filter] that you sync to the iris so we could effectively pull depth of field. It’s quite extreme. You could pull five stops of depth of field! So we could go from a T8 to a 2. That thing kind of lived on the camera.
There were times where we’d say, ‘It’s too much. Let’s look at it at a 5.6.’ So you set the iris to a 5.6, the polarizer [ND filter] compensates and now you’re looking at the same scene but with less depth of field. It was nice to be able to use focus and iris as a storytelling tool instead of just an exposure tool.
There are portions of the movie where we could actually dynamically change the depth of field in the frame. We called it a ‘depth of field rack’. Instead of a focus rack, where you’re shifting the plane of focus from one part of the frame to another, we could actually expand and contract the depth of field, and it’s very subtle. Unless you’re really watching for it, it’s hard to tell, but it happens several times in the movie.
- Erik Messerschmidt ASC talking to Filmmaker and Deadline
In an interview for the first issue of the new Cinematography World Magazine Messerschmidt reports:
“We were generally shooting at T8, T11 and sometimes at T16 to achieve the deep depth-of-field we wanted. But when you do that, you lose the ability to use focus as a storytelling tool, in terms of helping the audience know where to look in the frame. There were many moments where we needed that visual device, to punctuate a scene, isolate certain characters, or to pull the depth-of-field as if we were racking focus in-camera. Cinefade does this extremely well.”
- Erik Messerschmidt ASC talking to Cinematography World
Erik goes into more detail about his thought process behind using the Cinefade and admits he tried to be subtle with it. The hope was that if you are not actively looking for it, you would just be affected by the results. Most of the story is told objectively as we observe Mank going through his day. The Cinefade effect helped in communicating a shift in his state-of-mind, slightly modifying the point of view and isolating Mank from the rest of the environment.
One of the things that we rely on heavily in cinematography is using focus to tell the audience which part of the frame to look at, and generally, that’s because the other parts of the frame are out of focus. In deep focus photography, it’s different. You really have to rely on light and composition to direct the audience’s eye, making sure that the audience is appreciating what’s important in the shot.
- Erik Messerschmidt ASC talking to Deadline
After having lost the election, Mank receives a telephone call from the inebriated Shelly Metcalf. The depth of field gradually becomes shallow, guiding the viewers’ eyes away from Sara (Mank’s wife) and the busy background, allowing us to focus on Mank’s conversation and his facial expressions. The transition also reflects his change in state-of-mind: Caring for his friend has suddenly become an urgent priority and the depth of field does not change back until after the call gets disconnected and Mank informs his wife of the situation.
Mank is at a low point, feeling ‘washed-up’, when his brother Joe admits as he is departing, that the screenplay is his best so far. Mank watches his brother drive off into the distance as the depth of field gradually transitions from deep to shallow focus, keeping Mank sharp.
Rita in the background of the shot becomes blurry, drawing attention away from her to make sure the viewer concentrates on Mank as he regains his composure and seems filled with a renewed sense of confidence.
The transition is very subtle, barely noticeable, yet still effective in guiding the viewer’s eyes and in communicating the change in mood. In combination with the brilliant understated acting and direction (I wonder how many takes Fincher made Oldman do to get the subtleties of his performance just right) the Cinefade is able to highlight an important moment in the narrative, bringing the scene and indeed this chapter of the story to an end.
It is also important to appreciate the skill of the focus pullers and Messerschmidt praises his A-Camera First Assistant Alex Scott along with his colleagues in the camera department as being amongst the best in the business. On a movie of this calibre, there is no tolerance in terms of soft focus and on set the team is often rushed and under duress. The Cinefade was a new system to learn but they quickly got used to it and were able to perform exceptionally, even when the depth of field suddenly drops down to mere inches.
“The Cinefade effect usually lived between 5-6 stops, so that’s between T11 to T2 mostly. We wouldn’t always go to 1.4 but there were instances, for example in the bungalow sequences that we shot from an 8 to a 1.4. The difference between 8 and 11 in terms of depth of field in a small room when you’re focussed at 10 or 12 feet is not that substantial. If you’re in a large space and your hyperlocal length is at 15 feet and you’re trying to hold focus at 3 feet and at infinity, you kind of need to be at an 11 I think but in the bungalow where most of our focal range was between 4 feet and 15 feet we could quite effectively work at an 11 which helped me in terms of lighting.”
- Erik Messerschmidt ASC
After lots of inner turmoil, Mank finally reveals to Orson Welles that he wants to be credited for writing the screenplay. This is an absolute bombshell to Orson and a pivotal moment close to the end of the film. The Cinefade effect gradually blurs John Houseman in the background, as he is dismissed by Orson, who only has eyes for Mank and is becoming increasingly angry.
Rita confronts Mank but when she realises that he isn’t responding, she is shocked and inhales sharply as the depth of field becomes shallow and the background softens. It’s a subtle shift to support the change of her mindset and can be easily missed but it is arguably felt by the audience on a subconscious level.
Mank’s friends are trying to convince him to walk away from the screenplay and after a civilised marital confrontation, Mank’s wife Sara walks out of the room, leaving Mank all alone with his thoughts. Gradually the depth of field becomes shallow and the cluttered room becomes blurry, further isolating Mank sitting in his chair at the edge of frame. The Cinefade effect guides the viewer’s eyes to the edge of frame, making sure we notice as Mank takes a deep breath in and sighs out. Again, it’s a subtle effect, right at the end of the scene.
Messerschmidt reveals that this Cinefade shot was another game-time decision where they spontaneously decided to throw the system on and try it out.
“It’s really easy to drop into the camera. The assistants got used to it and thankfully it’s not a cumbersome thing to add.”
- Erik Messerschmidt ASC
One of Messerschmidt’s favourite shots is actually a combination of a focus pull with a shift in depth of field. We’re shooting into the kitchen across Mank who is in focus. As Rita walks into the kitchen to make tea, we throw the focus to her. Once she has delivered her line, the focus pulls back to Mank as the depth of field decreases at the same time and we end up with the same shot as the first but with a shallow depth of field with the kitchen completely out of focus. Then she walks forward with the tea and we bring the depth of field back out just enough to hold them both in focus.
If you really analyse that shot, it’s a really complex thing that’s going on. I don’t think the audience really understands the complexity of that cause its so subtle. It looks like a focus pull but in fact it is not. That’s one of my favourites cause it’s a little bit tricky.
- Erik Messerschmidt ASC
In order to shoot at a deep depth of field, a lot of light is necessary to achieve the required small f-stop. This is especially true if a Cinefade scene is planned, as the VariND filter swallows 1.5 stops of light at full transmission.
During the camera tests at Panavision and Keslow, Messerschmidt tested both film and digital cameras, finally settling on digital cameras for their added flexibility and control over the final image. When it came to deciding between a colour or black-and-white camera, the images of the black-and-white camera, which has the Bayer filter removed to achieve a luminance-only output, produced superior results over the images from colour cameras with desaturation applied in post.
Another added benefit of a monochrome camera is that the removal of the Bayer filter brings about 1.5 stops more speed out of the camera. Messerschmidt could comfortably rate the RED Helium 8K Monochrome camera at 3200ASA. They did use 20Ks, 16Ks and fresnels to get the hard-light, low-key, deep-focus look and certainly more light was needed than on a usual shoot but not as when shooting at 800ASA and f11.
To control all this light, the Cinefade VariND “lived on the camera”, according to Messerschmidt, which enabled him and his AC Alex Scott to precisely dial in the required amount of ND filtration required, remotely from the cmotion cPro hand unit or directly on the filter itself to maintain a consistent stop. This is especially handy when shooting outdoors with varying cloud coverage or whenever the camera is inaccessible
“We primarily used the Cinefade VariND as an exposure tool for the exteriors. The ability to leave the iris where you want it and adjust exposure with the VariND is fantastic. It’s particularly useful on a crane, because you don’t have to pull the crane down to adjust the ND.”
- Erik Messerschmidt ASC
Let us know in the comments or on social media @cinefade your thoughts on how Messerschmidt used a variable depth of field in Mank and how a motorised VariND could benefit your own productions. Find out more about the Cinefade variable depth of field effect and the VariND’s other applications for professional filmmakers.