testing

Undisclosed Project: Experimentation

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The main event of last week’s prep was a test at Panavision of the Arri Alexa XT, Red Gemini and Sony F55, along with Cooke Panchro, Cooke Varotal, Zeiss Superspeed and Angenieux glass. More on that below, along with footage.

The week started with Zoom meetings with the costume designer, the make-up artist, potential fight choeographers and a theatrical lighting designer. The latter is handling a number of scenes which take place on a stage, which is a new and exciting collaboration for me. I met with her at the location the next day, along with the gaffer and best boy. After discussing the stage scenes and what extra sources we might need – even as some of them were starting to be rigged – I left the lighting designer to it. The rest of us then toured the various rooms of the location, with the best boy making notes and lighting plans on his tablet as the gaffer and I discussed them. They also took measurements and worked out what distro they would need, delivering a lighting kit list to production the next day.

Meanwhile, at the request of the producer, I began a shot list, beginning with two logistically complex scenes. Despite all the recces so far, I’ve not thought about shots as much as you might think, except where they are specified in the script or where they jumped out at me when viewing the location. I expect that much of the shot planning will be done during the rehearsals, using Artemis Pro. That’s much better and easier than sitting at home trying to imagine things, but it’s useful for other departments to be able to see a shot list as early as possible.

So, the camera tests. I knew all along that I wanted to test multiple cameras and lenses to find the right ones for this project, a practice that is common on features but which, for one reason and another, I’ve never had a proper chance to do before. So I was very excited to spend Wednesday at Panavision, not far from my old stomping ground in Perivale, playing around with expensive equipment.

Specifically we had: an Arri Alexa – a camera I’m very familiar with, and my gut instinct for shooting this project on; a Sony F55 – which I was curious to test because it was used to shoot the beautiful Outlander series; and a Red Gemini – because I haven’t used a Red in years and I wanted to check I wasn’t missing out on something awesome.

For lenses we had: a set of Cooke Panchros – again a gut instinct (I’ve never used them, but from what I’ve read they seemed to fit); a set of Zeiss Superspeeds – selected after reviewing my 2017 test footage from Arri Rental; a couple of Cooke Varotal zooms, and the equivalents by the ever-reliable Angenieux. Other than the Angenieux we used on the B-camera for The Little Mermaid (which I don’t think we ever zoomed during a take), I’ve not used cinema zooms before, but I want the old-fashioned look for this project.

Here are the edited highlights from the tests…

You’ll notice that the Sony F55 disappears from the video quite early on. This is because, although I quite liked the camera on the day, as soon as I looked at the images side by side I could see that the Sony was significantly softer than the other two.

So it was down to the Alexa vs. the Gemini, and the Cookes vs. the Superspeeds. I spent most of Thursday and all of Friday morning playing with the footage in DaVinci Resolve, trying to decide between these two pairs of very close contenders. I tried various LUTs, did some rough grading (very badly, because I’m not a colourist), tested how far I could brighten the footage before it broke down, and examined flares and bokeh obsessively.

Ultimately I chose the Cooke Panchros because (a) they have a beautiful and very natural-looking flare pattern, (b) the bokeh has a slight glow to it which I like, (c) the bokeh remains a nice shape when stopped down, unlike the Superspeeds’, which goes a bit geometric, (d) they seem sharper than the Superspeeds at the edges of frame when wide open, and (e) more lengths are available.

As for the zoom lenses (not included in the video), the Cooke and the Angenieux were very similar indeed. I chose the former because it focuses a little closer and the bokeh again has that nice glow.

I came very close to picking the Gemini as my camera. I think you’d have to say, objectively, it produces a better image than the Alexa, heretical as that may sound. The colours seem more realistic (although we didn’t shoot a colour chart, which was a major oversight) and it grades extremely well. But…

I’m not making a documentary. I want a cinematic look, and while the Gemini is by no means un-cinematic, the Alexa was clearly engineered by people who loved the look of film and strove to recreate it. When comparing the footage with the Godfather and Fanny and Alexander screen-grabs that are the touchstone of the look I want to create, the Alexa was just a little bit closer. My familiarity and comfort level with the Alexa was a factor too, and the ACs felt the same way.

I’m very glad to have tested the Gemini though, and next time I’m called upon to shoot something great and deliver in 4K (not a requirement on this project) I will know exactly where to turn. A couple of interesting things I learnt about it are: (1) whichever resolution (and concomitant crop factor) you select, you can record a down-scaled 2K ProRes file, and this goes for the Helium too; (2) 4K gives the Super-35 field of view, whereas 5K shows more, resulting in some lenses vignetting at this resolution.

Undisclosed Project: Experimentation

Exposure Part 4: ISO

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So far in this series we have seen how we can adjust exposure using aperture, which affects depth of field, ND filters, which can help us retain the depth of field we want, and shutter angle, which affects motion blur and flickering of certain light sources. In this final part we’ll look at ISO, perhaps the most misunderstood element of exposure, if indeed we can technically classify it as part of exposure at all!

 

What is ISO?

The acronym stands for International Organization for Standardization, the body which in 1974 combined the old ASA (American Standards Association) units of film speed with the German DIN standard. That’s why you’ll often hear the terms ISO and ASA used interchangeably.

Two different cameras filming the same scene with the same filters, aperture and shutter settings will not necessarily produce an image of equal brightness, because the ways that their electronics convert light into video signals are different. That is why we need ISO, which defines the relationship between the amount of light reaching the sensor (or film) and the brightness of the resulting image.

For example, a common ISO to shoot at today is 800. One way of defining ISO 800 is that it’s the setting required to correctly expose a key-light of 12 foot-candles with a lens set to T2.8 and a 180° shutter at 24fps (1/48th of a second).

If we double the ISO we double the effective sensitivity of the camera, or halve the amount of light it requires. So at ISO 1600 we would only need 6 foot-candles of light (all the other settings being the same), and at ISO 3200 we would need just 3 foot-candles. Conversely, at ISO 400 we would need about 25 foot-candles, or 50 at ISO 200.

 

A Flawed Analogy

Note that I said “effective” sensitivity. This is an important point. In the photochemical world, ISO indeed denotes the light sensitivity of the film stock. It is tempting to see digital ISO as representing the sensitivity of the sensor, and changing the ISO as analogous to loading a different film stock. But in reality the sensitivity of a digital sensor is fixed, and the ISO only determines the amount of gain applied to the sensor data before it is processed (which may happen in camera if you’re shooting linear or log, or in post if you’re shooting RAW).

So a better analogy is that altering the ISO is like altering how long the lab develops the exposed film negative for. This alters the film’s exposure index (EI), hence some digital cameras using the term EI in their menus instead of ISO or ASA.

We can take this analogy further. Film manufacturers specify a recommended development time, an arbitrary period designed to produce the optimal image. If you increase (push) or decrease (pull) the development time you will get a lighter or darker image respectively, but the quality of the image will be reduced in various ways. Similarly, digital camera manufacturers specify a native ISO, which is essentially the recommended amount of gain applied to the sensor data to produce what the manufacturer feels is the best image, and if you move away from that native ISO you’ll get a subjectively “lower quality” image.

Compare the graininess/smoothness of the blacks in these images from my 2017 tests. Click to enlarge.

The most obvious side effect of increasing the ISO is more noticeable noise in the image. It’s exactly the same as turning up the volume on an amplifier; you hear more hiss because the noise floor is being boosted along with the signal itself.

I remember the days of Mini-DV cameras, which instead of ISO had gain; my Canon XL1 had gain settings of -3dB, +6dB and +12dB. It was the exact same thing, just with a different name. What the XL1 called 0dB of gain was what we call the native ISO today.

 

ISO and Dynamic range

At this point we need to bring in the concept of dynamic range. Let’s take the Arri Alexa as an example. This camera has a dynamic range of 14 stops. At its native ISO of 800, those 14 stops of dynamic range are equally distributed above and below “correct” exposure (known as middle grey), so you can overexpose by up to seven stops, and underexpose by up to seven stops, without losing detail.

If you change the Alexa’s ISO, those limits of under- and overexposure still apply, but they’re shifted around middle grey. For example, at 400 ISO you have eight stops of detail below middle grey, but only six above it. This means that, assuming you adjust your iris, shutter or filters to compensate for the change in ISO, you can trade-off highlight detail for shadow detail, or vice versa.

Imagine underexposing a shot by one stop and bringing it back up in post. You increase the highlight detail, because you’re letting half the light through to the sensor, reducing the risk of clipped whites, but you also increase the noise when you bring it up in post. This is basically what you’re doing when you increase your ISO, except that if you’re recording in linear or log then the restoration of brightness and increase in gain happen within the camera, rather than in post with RAW.

Note the increased detail in the bulb at higher ISOs. Click to enlarge..

We can summarise all this as follows:

Doubling the ISO…

  • increases overall brightness by one stop, and
  • increases picture noise.

Then adjusting the exposure to compensate (e.g. closing the iris one stop)…

  • restores overall brightness to its original value,
  • gives you one more stop of detail in the highlights, and
  • gives you one less stop of detail in the shadows.

Alternatively, halving the ISO…

  • decreases overall brightness by one stop, and
  • decreases picture noise.

Then adjusting the exposure to compensate (e.g. opening the iris one stop)…

  • restores overall brightness to its original value,
  • gives you one less stop of detail in the highlights, and
  • gives you one more stop of detail in the shadows.

 

Conclusion

This brings me to the end of my exposure series. We’ve seen that choosing the “correct” exposure is a balancing act, taking into account not just the intended brightness of the image but also the desired depth of field, bokeh, lens flares, motion blur, flicker prevention, noise and dynamic range. I hope this series has helped you to make the best creative decisions on your next production.

See also: “6 Ways to Judge Exposure”

Exposure Part 4: ISO

A Cinematograper Prepares

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One of the things which I believe separates a good director of photography from a bad one is preparation. On a big production you may have weeks of paid, full-time prep, but on a micro-budget movie you may be lucky to have a single meeting before the shoot. In the latter case you’ll have to use your initiative, put in the time for free, and use Skype a lot, but either way the quality of the prep can make or break the production.

Here are ten things a DP should do to set themselves up for success before the camera rolls. This is not intended to be an exhaustive list, rather it’s a run-down of the things which I have found to bear most fruit later on in the production.

 

1. Get inside the director’s head.

Some directors will come to you with a beautiful set of storyboards, concept art and reference images, but many won’t. Many will simply have an idea in their head of how they want it to look, and it’s your job to find out what that vision is. Often this will happen before full-time prep begins. It will consist of watching movies together, pouring over books of photos, sharing Pinterest boards or Dropboxes full of images, all the while discussing what they do and don’t like. The aim is to get such a clear idea of their vision that when you set up a shot you’ll deliver the mood they’re looking for first time.

 

2. Work with the art department.

Chatting over a set model helps identify potential lighting or lensing problems before construction begins.

The next person to get in sync with is the production designer. This is an incredibly important and symbiotic relationship; you have the power to completely destroy each others’ work, or to make each other look like geniuses! Two things you should talk about early on with the designer are the colour palette of the film (and any palettes specific to certain locations, plot threads or characters) and the aspect ratio: does the shape of the sets being designed fit the shape of the frame you’re planning to compose? Next you’ll want to discuss each set and the position of windows and practicals within it, to ensure that you’ll be able to get the lighting angles you need. For their part, the designer will want to quiz you on where the key camera positions will be, and the rough lens lengths you’ll be using, so they know where to put in the most detail and the important bits of dressing.

 

3. Get to know the needs of the other H.o.D.s.

Although the production designer is the most important head of department for a DP to work with, they are by no means the only one. The visual effects supervisor is increasingly a key collaborator; you should discuss the look you’re going for and how that will integrate with the VFX, and whether plates need to be shot at a higher resolution, in RAW, or any other technical requirements. You should familiarise yourself with the costume designs and discuss how those will integrate with the overall look. Similarly the make-up department will want to talk about about lens filtration, coloured lighting and anything else that may affect how their work looks. The line producer is a crucial person to get on the good side of. Sooner or later you’ll have to ask them for something expensive and unexpected, and they’re much more likely to say yes if you have tried to help them earlier on, by reducing your equipment list for example, or by hiring local camera assistants to save on accommodation costs.

Read my article on collaborating with other departments for more on this topic.

 

4. Check sun paths at locations.

Checking my compass at the stone circleWhen you start to scout the locations, you’ll want to pay careful attention to the direction of the sun. Which windows will it come through as it moves around over the course of the day? Are those trees or buildings likely to shadow that park bench where the characters will be sitting? With a bit of experience – and a compass, if it’s cloudy – you can estimate this, or use apps like Sun Tracker and Helios which are designed for exactly this purpose. For interiors, windows that never get direct sunlight are most convenient, allowing you to light them artificially, and thus constantly, without having to flag the real sun. For exteriors, shooting into the sun is generally most desirable, for the beauty of the backlight and the softness of the reflected fill. Of course, there will always be compromises with the other demands of the production.

See my article on sun paths for more on this.

 

5. Develop the shot list with the director.

Each director has a different process, but often they will draft a shot list on their own before passing it to you for feedback. There are many things for a DP to consider when going through this list. Do the shots reflect the style and visual grammar you both discussed earlier? (If not, has the director had a change of heart, or have they simply forgotten? Directors have a lot to think about!) Do the shots provide enough coverage for the editor? Are there too many shots to realistically accomplish on schedule? (Very often there are!) What grip equipment will the camera movements require? Are any special lenses or filters required, e.g. a macro lens for an extreme close-up of an eye?

 

6. Shoot tests.

Testing is a crucial part of the prep for both technical and creative reasons. Usually you will want to test a few different cameras and lens sets, to see which best serve the story. For example, a period film lit with a lot of genuine candlelight may work best on a sensitive camera like the Panasonic Varicam combined with soft fall-off lenses like Cooke S4s, while a sci-fi thriller might be suited to a Red or Alexa and a set of anamorphics for those classic flares. Until you’ve tested them and compared the images side by side though, you can’t be sure, and neither can the director and producers. Often costume and make-up tests will be requested, which may be combined with the camera tests to see how the different sensors render them, or maybe done separately once the camera kit is locked down. These tests are also a great opportunity for the DP to demonstrate for the director the type of lighting you plan to use to, and to make sure you really are on the same page. Ideally a DIT (digital imaging technician) will be available to grade the test footage, developing LUTs (look-up tables) if required, and providing proof of concept for the finished look of the movie.

Check out my tests of Alexa ISO settings, spherical lenses and anamorphic lenses.

 

7. Discuss the schedule.

Once the 1st AD has drafted the shooting schedule, they will show it to the DP for feedback. When determining how much can be done in a day, the 1st AD is thinking of the script page count, and they may not have seen a shot list at this point. Along with the director, the DP must bring any concerns they have about the schedule to the 1st AD in prep, or forever hold your peace! Is there enough time to get those tricky camera moves you’ve planned? Has the re-light time for the reverse been factored in? Have things been arranged in a logical order for lighting, or will things have to be torn down and put back up again later? Does the schedule permit things to be shot at the best time of day for light? Are the night scenes actually scheduled at night or will the windows have to be blacked out? Are there critical close-ups towards the end of the schedule, when the cast will be tired and no longer look their best?

For more detail on this, check out my article about things to look for in a schedule.

 

8. Get to know the faces of your cast.

Legendary DP John Alton, ASC tests lighting angles with Joan Bennett

However good-looking the talent may be, they will always look better under certain types of lighting than others. Often you will figure out what suits each actor after a week or so of shooting, but ideally you want to find out before principal photography begins. You can do this during testing, if the cast are available and you have enough time – trying out different key angles, fill levels, backlight and lenses to see what works best for their individual faces. Apart from anything else, this is a great way to establish trust with the cast right from the start, assuring them that they are in safe hands. If testing isn’t possible, watch some of their previous work, looking carefully at how they have been photographed.

 

9. Mark up your script.

There’s no point in having lots of great ideas in preproduction if you forget them when you’re on set. Everyone has a different system, but you may wish to mark up your script and/or shot list. This could include using coloured highlighters to differentiate day and night scenes at a glance, underlining any references to mood or camera angles in the stage directions, or indicating beats in the development of the story or characters which need to be reflected in how things are lit or shot.

 

10. Plan your lighting.

Shop lighting planEveryone likes to get rolling as soon as possible after call time, and a big factor in achieving this is how quickly you can light. Ideally you will have planned the broad strokes of the lighting in preproduction, and communicated that plan to the gaffer. Budget permitting, the lighting crew can even pre-rig the set so that only tweaking is required when the whole unit arrives. In this case you’ll need to have been very clear and specific about what you want set up and where, drawing diagrams or approving those which the gaffer has drawn up. Often you’ll need to know the rough blocking of the scene before you can plan the lighting, so you should make sure the director indicates their intentions for this during scouts.

 

Every film is different, but follow the steps above and you’ll be well on your way to an efficient and productive shoot in 2018. Happy new year!

A Cinematograper Prepares

Camerimage 2017: Monday

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This week I attended Camerimage for the first time. Centred around the Opera Nova theatre beside the river Brda in Bydgoszcz, Poland, Camerimage is an international film festival celebrating the art of cinematography. It’s a bit like Cannes for DPs, but colder. This is the first part of my account of my three days at the annual hub of motion picture imaging.

The Ryanair flight was dirt cheap but trouble free, and at 9:50am I found myself on the tarmac of Bydgoszcz airport. There I met David Shapton and Matt Gregory, founders of Red Shark News, for the first time. I’ve been contributing articles to Red Shark for a few months so it was nice to finally meet these gentlemen in person.

A taxi (also dirt cheap) dropped me at the Opera Nova – only about three miles from the airport – where I picked up my pass and goodie bag. Bizarrely, said goodies included an Ikea catalogue. How did they know that us DPs love flat-pack furniture so much?

 

Canon Workshop: Stephen Goldblatt

From the Opera Nova I hurried to a college across the river, where the sports hall formed the venue for a Canon workshop run by Stephen Goldblatt, ASC, BSC, the man behind the lens for the likes of Lethal Weapon 2 and Batman Forever. The blurb for this workshop described Goldblatt as “a master of low light shooting”, and it was certainly pitch black when I walked in a few minutes late, and gingerly picked my way around to the far side of the hall to find a seat.

Lighting through lace

On a purpose-built bedroom set, Goldblatt was recreating lighting from the Robert Redford / Jane Fonda romantic drama Our Souls at Night, shot on the Sony F55 and Canon C300 Mark II. To practical lamps on either side of the bed he added egg-crated tungsten soft-boxes to beef up each one. He simulated moonlight through an imagined off-camera window by placing a lace curtain in front of a blue-gelled lamp and blowing it gently with a fan. An additional egg-crated soft-box provided a low level of blue toplight.

As he worked, Goldblatt revealed how he doesn’t miss ceulloid, loving how relatively easy it is now to light night exteriors or moving car scenes. “But just because you don’t need much light,” he cautioned, “it doesn’t mean you don’t want to control it.” Other developments coming down the pipe do not inspire him so much; he feels that high resolutions and HDR are unnecessary, pushed by marketing people rather than creatives.

He placed great emphasis on the importance of the eyes. “A common failing of newer DPs is that they worry more about the set than the eyes,” he said, before explaining how he will often walk beside the handheld camera with a torch, providing eye-light. He also stressed the importance of eye-lines. Although in any one shot it’s not that important how wide or tight the eye-line is, or how high or low, across the two hours of a feature film the decisions have a cumulative effect.

Trying out a Xeen lens in the exhibition hall

Goldblatt no longer uses a light meter. “Trust your eye, develop your eye,” he advised, adding that you must have a strong voice to remain in control of the images through postproduction.

After grabbing lunch, I returned to the Opera Nova to browse the exhibition hall. This closely resembled a mini BSC Expo or Media Production Show, with all the major camera and lens manufacturers displaying their wares, along with several lighting companies. I had a play with some of the cameras, including the actual Alexa 65 used on Rogue One.

Then I met up with Chris Bouchard, one of The Little Mermaid‘s two directors, who had arrived in Poland the previous day. We sauntered over to another venue, the MCK Orzeł, an independent cinema with a nice, chilled, film-buff-friendly atmosphere. The auditorium itself was packed though as we settled in for a seminar on “The Future of Digital Formats”.

 

Red Seminar: The Future of Digital Formats

Promoting Red’s Monstro sensor, the session was mostly about the benefits of shooting in high resolutions, and giving yourself the maximum flexibility in post. You can read my thoughts on both of those topics in upcoming Red Shark articles.

One of the speakers, Christopher Probst, ASC (DP of Mindhunter and technical editor of American Cinematographer magazine) made some interesting points about ISO. “Traditionally, low ISOs were used for bright scenes like day exteriors, and high ISOs were used for darker scenes like night exteriors,” he explained. “That was based on reducing the grain, getting the cleanest possible image on film.” He advised the opposite for digital capture. “Use a low ISO for nights to get more shadow detail, and a high ISO for days to get more highlight detail [in the sky, for example].”

“Independence Day: Resurgence” – DP: Markus Forderer, BVK

Another interesting nugget came from Markus Förderer, BVK. On Independence Day: Resurgence he switched between spherical, 1.3x anamorphic and 2x anamorphic lenses depending on the situation. For example, flatter lenses were better for wide shots – where anamorphics would distort straight lines – and for VFX work.

 

Hawk Vantage Seminar: Top cinematographers tell their Hawk stories

I ducked out of the Red session early so that I could pop back to the Opera Nova for the Hawk Vantage seminar, bumping into my Perplexed Music gaffer Sam Meyer on the way. Hawk were launching three new sets of lenses: MiniHawk (T1.7 hybrid anamorphics), Hawk Class-X (T2.2 2x anamorphics) and Hawk65 (T2.2).

A Hawk T1 in the exhibition hall

The MiniHawks in particular seem very exciting. Daniel Pearl, ASC showed us some stunning frame grabs from the upcoming Dennis Quaid vehicle Motivated Seller, shot using these lenses on Alexa Mini. Whilst having key advantages of spherical lenses (speed, small size, low weight, extremely close focus) the MiniHawks have a unique and beautiful cigar-shaped bokeh.

While Pearl had used the latest Hawks, Magdalena Górka, PSC had shot with some old ones, the C series, for Brad Silberling’s drama An Ordinary Man. “I had to frame everything centrally because that’s the only place that was sharp!” she laughed. Also addressing focus fall-off, Andrzej Bartkowiak, ASC (Speed, The Devil’s Advocate) stated, “I like anamorphic because the shallow depth of field allows you to direct the viewer’s eye more.”

Stuart Dryburgh, ASC (The Secret Life of Walter Mitty, Bridget Jones’s Diary) talked about shooting 1.3x anamorphic. He has done this on three-perf 35mm (to achieve a Scope aspect ratio), on an Alexa in 16:9 mode (again for 2.39:1) and on an Alexa in 4:3 mode (to get 1.85:1). He also recommended shooting on Super-16 with 1.3x glass, citing the example of Ed Sheeran’s “Thinking Out Loud” video, which Pearl shot.

Peter Flinckenberg, FCK (Upswing, Concrete Night) noted that, with the shift to digital acquisition, the DP is no longer a magician, “but you can bring back that magic with lighting and glass that has character.”

 

CW Sonderoptic: Exploring Large format cinematography & Leica lenses

I took my leave, dashing back to the MCK Orzeł for another lens-themed seminar, this time by CWSonderoptic, the makers of Leica. The first half of this panel revolved around a short film shot by Darius Khondji, ASC, AFC (Seven, Delicatessen) on an Alexa 65 with the new Leica Thalias.

The second half was all about Tod Campbell, DP of Stranger Things and Mr. Robot, focusing on the latter show. The second season of Mr. Robot was shot on Leica Summicrons after Campbell found that the Cookes used on season one distorted the many straight lines which became such a key part of the show’s unique look. “I look at season two as kind of the birth of the photography for the show,” he said. With a laugh he added: “Sorry that the lighting looks like shit in season one. I was learning!” (See my spherical lens tests for my own thoughts on Cookes and Leicas.)

One of my favourite shots from “Mr. Robot”

Campbell revealed that season three of Mr. Robot has a different look again, using much more camera movement and “twice as much atmos”. For this season he paired Canon K35 glass with an 8K camera, but due to the Canons’ low resolution he employed Leica Summiluxes for the wide shots.

He also shared some interesting information about his testing process, admitting that he doesn’t really know how other DPs test. He doesn’t use charts, he just makes it up. He always includes a candle, a practical lamp, some kind of highlight in the background, and random foreground objects (as background bokeh can differ from foreground bokeh).

 

Christopher Doyle Seminar

When the Leica seminar ended I went back to the Opera Nova, where Chris and I had dinner at the nice (and once again cheap – are you detecting a theme?) restaurant. Despite having got up at 4am (3am local time) I wasn’t feeling too tired, so we headed upstairs to the 10pm seminar by Christopher Doyle, HKSC (Hero, Lady in the Water). Many people were nursing beers, including Doyle himself, and the lecture theatre was dimly illuminated by mood lighting. Clearly this session was not going to be like the daytime ones.

“We’re going to fuck things up,” Doyle began, dispelling all doubts. He proceeded to talk disjointedly but entertainingly about his work on The White Girl and what I think was a separate film about a camera obscura. His oratory was liberally sprinkled with great one-liners, a few of which I reproduce here for your edification:

  • There are only three people in filmmaking: the actor, the audience and the cinematographer in between them.
  • If actors don’t feel loved, the performance will not come across on camera.
  • Give the idea the image it deserves.
  • [Vittorio] Storaro [legendary DP of Apocalypse Now amongst others] can’t tell you how to do it. You have to find it for yourself.
  • People in space – that’s what cinematography’s about.
  • The location is very important. It gives the energy, it imposes the style.
  • The lens doesn’t matter; it’s what it shows that’s important.
  • You never sleep because you care too much – that’s what filmmaking is.
With Chris Bouchard in front of the Opera Nova

Doyle also picked up on a piece of dialogue from a clip he screened: “What is it?” / “I don’t know yet.” It was a great summation of finding the essence of a shot, he said.

Having had our fill of aphorisms, Chris Bouchard and I slipped out to get a drink. The Cheat, the pop-up bar across the road, was absolutely packed, and my early morning was finally catching up with me, so I called it a night. The highstreet of Bydgoszcz was quiet and chilly as I walked briskly to my hotel, curiously located down a service road behind the city’s football stadium, reflecting on all that I had learnt that day.

Tune in next week for tales from my second day at Camerimage.

Camerimage 2017: Monday

Anamorphic Lens Tests

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Anamorphic cinematography, first dabbled with in the 1920s, was popularised by Twentieth Century Fox in the fifties as CinemaScope. Television was growing in popularity and the studios were inventing gimmicks left, right and centre to encourage audiences back into cinemas. Fox’s idea was to immerse viewers in an image far wider than they were used to, but with minimal modifications to existing 4-perf 35mm projectors. They developed a system of anamorphic lenses containing elements which compressed the image horizontally by a factor of two. By placing a corresponding anamorphosing lens onto existing projectors, the image was unsqueezed into an aspect ratio of 2.55:1, or later 2.39:1.

Since those early days of CinemaScope, anamorphic cinematography has become associated with the biggest Hollywood blockbusters. Its optical features – streak flares, oval bokeh and curved horizontal lines – have been seared into our collective consciousness, indelibly associated with high production values.

I’ve not yet been fortunate enough to shoot anamorphic, but I was able to test a few lenses at Arri Rental recently, with the help of Rupert Peddle and Bex Clives. Last week I wrote about the spherical lenses which we tested; our anamorphic tests followed the same methodology.

Again we were shooting on an Alexa XT Plus in log C ProRes 4444 XQ, this time in 4:3 mode, a resolution of 2048×1536. Since all of the lenses had a standard 2:1 anamorphosing ratio, the images unsqueezed to a super-wide 2.66:1 ratio. (This is because the lenses were designed to be used on 35mm film with space left to one side for the optical soundtrack.) You can see the full width of this ratio in the first split-screen image in the video, at 2:08, and in the second image below, but otherwise I have horizontally cropped the footage to the standard 2.39:1 ratio.

We tested the following glass:

Series Length Speed CF* Weight
Hawk V 35mm T2.2 30″ 5.6kg
Cooke Xtal 30mm T2.8 ? 3kg
Kowa Mirrorscope 40mm T2.2 36″ 1.15kg
Kowa Mirrorscope 30mm T2.3 ? ?

* CF = close focus

For consistency with the spherical lenses, we used lengths around 32mm, but in the anamorphic format this is a pretty wide lens, not a mid-range lens. We shot at T2.8, again for consistency, but I hear that many anamorphics don’t perform well wider than T4.

We were only able to test what Arri Rental happened to have on the shelves that day. The biggest and presumably most expensive was the Hawk V-series. Next  in size and weight was the Cooke Xtal – pronounced “crystal” – a 1970s lens based on the much-loved Speed Panchros. The smallest and lightest, was the Kowa Mirrorscope, with a list price of £1,200 per week for a set of four. (Sorry, I couldn’t find any pricing info for the others online.) Note that there isn’t really a 30mm Mirrorscope; to get this length you put a wide angle adapter on the 40mm. As this extra element decreases the optical performance, we tested it with and without, hence the two lengths.

Here’s the video…

 

Skin tones

Click on the image to see it at full quality.

To my eye, the Hawk has a fairly rich, warm skin tone, while the Cooke – as with the spherical S4 tested last week – seems a little grey and flat. The Kowa is inexplicably brighter than the other two lenses, which makes it hard to compare, but perhaps it’s a little cooler in tone?

 

Sharpness

Focus is more critical with anamorphic lenses than spherical ones. From a forum posting by Max Jacoby:

Anamorphic lenses have what is known as a “curved field of focus” that works similarly to the curved movie screens in some large Cinerama theatres. This is one reason that one needs to expose these lenses at a deeper stop. If one doesn’t, the curved field will not be covered by depth of field and either the edges or centre of the frame will be soft.

One day I’d like to re-test these lenses at a lower stop, T4 or T5.6, where they will all undoubtedly perform much better. But in this T2.8 test, on Bex’s face in the centre of frame, the Hawk V and the Kowa Mirrorscope 40mm – both almost a full stop from their maximum apertures – are clearly the sharpest of the bunch. The Cooke Xtal, which is wide open, is unsurprisingly softer. The 30mm adapter on the Mirrorscope completely destroys the image, not only making it very soft but also introducing colour aberration.

Now let’s look at the checkerboard at the side of frame and see if we can spot any differences in sharpness there…

It seems to me that the Kowa, both with and without the adapter, has a greater difference in sharpness between the centre and edges of frame than the the Hawk and Cooke. With the latter two lenses, the checkerboard is reasonably sharp, at least on the lefthand side, with some ghosting/blur visible towards the righthand side. The same thing can be observed on the chart in the flare tests at the end of the video.

 

Breathing & Bokeh

All of these lenses have a noticeable degree of breathe, which I suppose is to be expected from anamorphics. The Hawk V has roughly oval bokeh, the Cooke’s is more circular, while the Mirrorscope has interesting D-shaped bokeh.

 

Flare

The Hawk V doesn’t flare much at all, which is apparently due to the anamorphic element being in the middle of the lens, rather than at the front. The Kowa has a nice streak and glow around the light source, with a funky purple artefact on the opposite side of frame. But it’s the Cooke Xtal which provides the most classic lens flare, with a horizontal line across most of the frame and a partial star pattern around the source, despite the lens being wide open.

At the end of the video you can see how the flares develop on each lens as the light source moves horizontally across frame.

 

Distortion

A bulging effect is very obvious on all of these lenses, due to the focal lengths being quite wide for anamorphic. Notice how at 40mm on the Kowa Mirrorscope this curvature of the image is significantly reduced.

It’s hard to compare the levels of distortion because none of the focal lengths are exactly the same, except for the Cooke Xtal and the Kowa Mirrorscope with the 30mm adapter on. The Cooke’s top right and bottom left corners appear to be stretched away from the centre relative to the other two corners. I suppose that strange and funky stuff like this is exactly why you choose vintage glass.

Interestingly, the Cooke’s image appears a little tighter than the Kowa’s, which combined with my inability to find any evidence online of the existence of a 30mm Xtal, leads me to suspect we may have been given a mislabelled 32mm.

 

Conclusions

When we got to the end of our spherical tests and started putting the anamorphics on, I was shocked by the drop in sharpness. But as noted earlier, this is because anamorphics really need to be used with a smaller aperture than the T2.8 I often shoot at. If I learnt nothing else from this test, I learnt that anamorphic needs more light!

I would love to put the Cooke Xtal’s lovely flares and general vintage look to good use on a period movie one day. The Hawk V would be a good choice if I wanted the anamorphic look with warm, dynamic skin tones. The Kowa system seemed a little cheap and cobbled-together, but could well be a good solution for anamorphic on a budget, as long as I stayed away from the 30mm adapter!

I hope you’ve found these tests useful. Thanks again to 1st AC Rupert Peddle, 2nd AC Bex Clives and Arri Rental UK for making them possible.

Anamorphic Lens Tests

Spherical Lens Tests

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The other week I spent a day at Arri Rental in Uxbridge, in the Bafta Room no less, conducting various camera and lens tests. I’ve done a number a productions now where I wanted to test but there wasn’t the time or money, so for a while I’ve been meaning to go into Arri on my own time and do some general tests for my education and edification. An upcoming short provided the catalyst for me to get around to it at last.

Aided by 1st AC Rupert Peddle and 2nd AC Bex Clives, I tested a dozen lenses, some spherical, some anamorphic. Today I will cover the spherical lenses; next time I’ll look at the anamorphics.

 

Method

We shot on an Alexa XT Plus in log C ProRes 4444 XQ at 3.2K. In the video the image has been downscaled to 1080P and a standard Rec.709 LUT has been added.

I set the Alexa to ISO 800 and lit Bex to a T2.8 using a 650W tungsten fresnel bounced off poly. For fill I caught a little of the spill from the fresnel with a matte silver bounce board on the opposite side of camera. I placed fairy lights in the background to observe the bokeh (out of focus areas) and turned on a 100W globe during each take to see what the flare did.

We shot all the lenses at 2.8 – the stop I most commonly use – and also wide open (compensating with the shutter angle), but the direct 2.8 comparison proved most useful, so that’s mainly what you’ll see in the video. We tested a single length: 35mm or the closest available to it.

What we didn’t do was shoot grey-scale or colour charts, or do any testing of vignettes or distortion. (The day after doing these tests, Shane Hurlbut, ASC published an Inner Circle post about how to tests lenses, so I immediately learnt what my omissions were!)

We tested the following lenses:

Series Length Speed CF* Weight Price
Leica Summilux-C 29mm T1.4 18″ 1.7kg £27K
Arri/Zeiss Master Prime 35mm T1.3 14″ 2.2kg £16K
Cooke S4 32mm T2 6″ 1.85kg £14K
Leica Summicron-C 35mm T2 14″ 1.3kg £13K
Zeiss High Speed
(a.k.a. Superspeed Mk III)		 35mm T1.3 14″ 0.79kg £12K
(refurb)
Arri/Zeiss Ultra Prime 32mm T1.9 15″ 1.1kg £10K
Zeiss T2.1 32mm T2.1 24″ 0.45kg £4K
(used)
Canon 35mm T1.5 12″ 1.1kg £3K

* CF = close focus

Here’s the video…

 

Skin tones

Click the image to see it at best quality.

The Arri/Zeiss Master Prime and the two Leicas seem to have the most vibrant skin tones. To my eye, the Leicas have a slight creaminess that’s very pleasing. The Canon looks just a little cooler and less dynamic. I was surprised to find that the Cooke S4, the lens I’ve used most, appears to have a grey, flat skin tone compared with the Master Prime, Leicas and Canon. I would rank the Ultra Prime and Superspeed next, on a par except that the Ultra Prime has a noticeable magenta cast. My least favourite skin tones are on the Zeiss T2.1, which comparatively makes poor Bex look a little bit ill!

Some of the nuances will be lost in the YouTube and Jpeg compression, but this is a very subjective assessment anyway, so feel free to completely disagree with all of the above. Any of the differences noted above could be corrected by grading, to some extent . But remember that the lens is at the very start of the light’s journey from set to screen, and any wavelengths that don’t get through it are lost forever. It’s like fluorescent lamps with colours missing from the spectrum; you can’t put those back in in post.

 

Sharpness

I have to say, I’m unable to detect any difference in sharpness between the Master Prime, Cooke S4, Canon and Leicas. The Ultra Prime and Superspeed both look a hair softer, while the T2.1 is very soft.

 

Breathing

Breathing is the slight zooming effect that you get with some lenses when you pull focus. Looking at 4:44 in the video you can clearly see the differences in breathing between the eight lenses. Because this part of the video is showing a crop of the bottom left corner of the image, the breathing manifests as a shift to the left (zoom in) as the lens is racked closer (goes soft) and a shift to the right (zoom out) as it’s racked deeper (goes sharp).

All the Zeiss lenses except the Master Prime have a significant amount of breath when seen in isolation like this, but not enough to be noticeable to an audience in most real-world situations. The Cooke S4 has a little bit of breathe, and the Canon a hair less. The Master Prime and the Leicas are rock solid.

 

Bokeh

Small points of light, when thrown out of focus, most clearly demonstrate the bokeh pattern of a lens. The shape of the bokeh is determined by the number of iris blades and the shape of those blades. Generally a circle is preferred, because it’s a natural shape, but for certain stories a more unusual shape might be appropriate. The shape of the iris changes with the T-stop, hence the T2.8 and wide open images above.

Immediately noticeable is the difference in the Cooke S4’s bokeh between wide open (circular) and T2.8 (octagonal). All of the other lenses have round bokeh at T2.8, apart from the Superspeed, which has heptagonal (seven-sided) bokeh.

It’s entirely subjective which bokeh you prefer. The only other thing I’ll point out is that the Canon’s bokeh wide open is very fuzzy, with noticeable colour aberration, though this may be due to the bright highlight rather than the defocusing.

 

Flare

Flare patterns also vary with aperture. The smaller the aperture, the more of a star effect you will get, as the light interacts with the corners in the iris blades. The Summilux shows this most clearly, with a pronounced star at T2.8 (two stops down from its maximum aperture) and almost none when wide open. The Cooke S4 also has a nice star pattern at T2.8. With the other lenses it’s much more subtle, and the Canon has almost none.

 

Conclusions

The real revelations in these tests, for me, were the Leicas. The Summilux in particular is a beautiful lens, with rich, dynamic skin tones, nice bokeh, no breathing, plus the bonus of nice star flares. I will definitely be looking to work with this glass in the future, although given the price tag that may be optimistic!

The Summicron also performed incredibly well, matching the more expensive Summilux and Master Prime in every respect except speed. I can see this becoming my new go-to lens.

The Master Prime of course produced a beautiful, sharp, clean image, but it lacks character. It might work nicely for science fiction, a drama requiring a neutral look, or something where filtration was being used to give the image character.

The Canon impressed me too – no mean feat given that it’s the cheapest lens we tested. With nice skin tones and attractive flares, I could see this working well for a romantic movie.

The Zeiss T2.1 did not appeal to me, with poor sharpness and cold, washed-out skin tones, so I would avoid it.

The Superspeed is a decent lens, but in most cases I’d plump for an Ultra Prime instead. Ultra Primes are certainly easier to work with for the 1st AC, and have proven to be a good workhorse lens for drama. (I shot Above the Clouds on them.)

The Cooke S4 has been my go-to glass up to now, and while it will probably remain my first choice for period pieces, due to its gentle focus fall-off, I’m excited to try some of the other glass in this test on other productions.

I’ll say it one last time: this is all subjective. Our visual preferences are what make every director of photography unique.

Tune in next week when I’ll look at the anamorphic lenses: Hawk-V, Cooke Xtal and Kowa Mirrorscope.

Spherical Lens Tests

Alexa ProRes ISO Tests

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My Cousin Rachel

I’ve shot three features on Arri Alexas, but I’ve never moved the ISO away from its native setting of 800 for fear of noise and general image degradation. Recently I read an article about the cinematography of My Cousin Rachel, in which DP Mike Eley mentioned shooting the night scenes at ISO 1600. I deliberately set off for the cinema in order to analyse the image quality of this ISO on the big screen. Undoubtedly I’ve unwittingly seen many things that were shot on an Alexa at ISO 1600 over the past few years, but this was the first time I’d given it any real thought.

To my eye, My Cousin Rachel looked great. So when I was at Arri Rental the other week testing some lenses, I decided to shoot a quick ISO test to see exactly what would happen when I moved away from the native 800.

But before we get to the test footage, for those of you unsure exactly what ISO is, here’s an introduction. The more experienced amongst you may wish to skip down to the video and analysis.

 

What is ISO?

A revised and updated version of this section is available.

ISO is a measure of a camera’s light sensitivity; the higher the ISO, the less light it requires to expose an image.

The acronym actually stands for International Organization for Standardization [sic], the body which in 1974 combined the old ASA (American Standards Association) units of film speed with the German DIN standard. That’s why you’ll often hear the terms ISO and ASA used interchangeably. On some cameras, like the Alexa, you’ll see it called EI (Exposure Index) in the menus.

A common ISO to shoot at today is 800. One way of defining ISO 800 is that it’s the sensitivity required to correctly expose a key-light of 3 foot-candles with a lens of T-stop 1.4 and a 180° shutter at 24fps, as we saw in my Barry Lyndon blog.

If we double the ISO we double the effective sensitivity of the camera, or halve the amount of light it requires. So at ISO 1600 we would only need 1.5 foot-candles of light (all the other settings being the same), and at ISO 3200 we would need just 0.75 foot-candles. Conversely, at ISO 400 we would need 6 foot-candles, or 12 at ISO 200. Check out this exposure chart if it’s still unclear.

ISO is one of the three corners of the Exposure Triangle, well-known to stills photographers the world over. You can read my posts on the other two corners: Understanding Shutter Angles and F-stops, T-stops and Optical Density.

Just as altering the shutter angle (exposure time) has the side effect of changing the amount of motion blur, and altering the aperture affects the depth of field, so ISO has its own side effect: noise. Increase the ISO and you increase the electronic noise in the picture.

This is because turning the ISO up causes the camera to electronically boost the signals it’s receiving from the sensor. It’s exactly the same as turning up the volume on an amplifier; you hear more hiss because the noise floor is being boosted along with the signal itself.

I remember the days of Mini-DV cameras, which instead of ISO had gain; my Canon XL1 had gain settings of -3dB, +6dB and +12dB. It was the exact same thing, just with a different name. What the XL1 called 0dB of gain was what today we call the native ISO. It’s the ISO at which the camera is designed to give the best images.

 

ISO and Dynamic Range

The Alexa has a dynamic range of 14 stops. That means it can simultaneously record detail in an area of brightness x and an area of brightness x times 2 to the power 14. At its native ISO of 800, those 14 stops of dynamic range are equally distributed above and below “correct” exposure (known as middle grey), so you can overexpose by up to 7 stops, and underexpose by up to 7 stops, without losing detail.

If you increase the ISO, those limits of under- and overexposure still apply, but they’re effectively shifted around middle grey, as the graphic to the left illustrates. (The Pro Video Coalition post this graphic comes from is a great read if you want more detail.) You will see the effects of this shifting of dynamic range very clearly in the test video and images below.

In principle, shooting at ISO 1600 is the same as shooting at ISO 800, underexposing by a stop (giving you more highlight detail) and then bringing it back up a stop in post. The boosting of the signal in that case would come right at the end of the image path instead of near the beginning, so the results would never be identical, but they’d be close. If you were on a bigger project with a DIT, you could create a LUT to bring the exposure up a stop which again would achieve much the same thing.

All of the above assumes you’re shooting log ProRes. If you’re shooting Raw then everything is simply recorded at the native ISO and any other ISO you select is merely metadata. But again, assuming you exposed for that other ISO (in terms of iris, shutter and ND filters), you will effectively get that same dynamic range shift, just further along the pipeline.

If this all got a bit too technical for you, don’t worry. Just remember:

Doubling the ISO

  • increases overall exposure by one stop,
  • gives you one more stop of detail in the highlights,
  • gives you one less stop of detail in the shadows, and
  • increases picture noise.

Halving the ISO

  • decreases overall exposure by one stop,
  • gives you one less stop of detail in the highlights,
  • gives you one more stop of detail in the shadows, and
  • decreases picture noise.

 

The Test

I lit the subject, Rupert “Are You Ready?” Peddle, with a 650W tungsten fresnel bounced off poly, and placed a 40W candle globe and some LED fairy lights in the background to show highlight clipping. We shot the tests in ProRes 4444 XQ on an Alexa XT Plus with a 32mm Cooke S4, altering the shutter angle to compensate for the changing ISOs. At ISO 400 the shutter angle was maxed out, so we opened the lens a stop for ISO 200.

We tested five settings, the ones corresponding to a series of stops (i.e. doublings or halvings of sensitivity): 200, 400, 800, 1600 and 3200. I have presented the tests in the video both as recorded in the original log C, and with a standard Rec.709 LUT.

You’ll need to watch the video at full-screen at 1080P to have any chance of seeing the differences, and even then you might see the compression artefacts caused by the noise more than the noise itself. Check out the stills below for a clearer picture of what’s going on. (Click on them for full resolution.)

 

Analysis

To me, the most important thing with every test is how skin tones are rendered. Looking at the original ProRes of these comparisons I think I see a little more life and vibrance in the skin tones at lower ISOs, but it’s extremely subtle. More noticeable is a magenta shift at the lower ISOs versus a green shift at higher ones. The contrast also increases with the ISO, as you can see most clearly in the log images.

At the lower ISOs you are not really aware of any noise in the picture. It’s only at ISO 1600 that it becomes noticeable, but I have to say that I really liked this level of noise; it gives the image a texture reminiscent of film grain. At ISO 3200 the noise is quite significant, and would probably be unacceptable to many people.

The really interesting thing for me was the shifting of the dynamic range. In the above comparison image, look at the globe in log – see how it starts off as one big white blob at ISO 200 and becomes more detailed as the ISO rises? Now look at the dark wall around the globe, both here and in the previous image – see how it subtly and smoothly graduates into darkness at the lower ISOs, but becomes a grainy mess at the higher ones?

I can see an immediate benefit to shooting at ISO 1600 in scenes lit predominantly with practicals. Such scenes tend to have a low overall level of illumination, while the practicals themselves often blow out on camera. Going to ISO 1600 would give me extra exposure and extra detail in the practicals. I would be sacrificing shadow detail, so I would have to be a little more careful not to underexpose any faces or other important elements of the frame, but I can deal with that. In fact, I often find myself determining my exposure in these types of scenes by how blown out the practicals are, wishing I could open up a little more to see the faces better but not wanting to turn the lamps into big white blobs. Increasing the ISO would be the perfect solution, so I’m very glad I did this test to alleviate my ungrounded fears.

What about scenarios in which a lower-than-native ISO would be useful? Perhaps a scene outside a building with an open door, where the dark interior is visible in the background and more detail is required in it. Or maybe one of those night scenes which in reality would be pitch black but for movie purposes have a low level of ambient light with no highlights.

I hope you’ve found this test as useful and interesting as I have. Watch this space or subscribe to my YouTube Channel for the lens test.

Thanks to Rupert Peddle, awesome steadicam op and focus puller – check out his site at pedhead.net – for appearing in front of the lens. Thanks also to Bex Clives, who was busy wrangling data from the lens tests while we were shooting these ISO tests, and of course Arri Rental UK.

Alexa ProRes ISO Tests