Why use a light meter at all? When photographing with modern digital cameras today, you rarely need such a device if you are not using professional lighting. You simply shoot in RAW and expose to the right, i.e. to the highlights (ETTR), and do the rest on the computer. With film, the whole thing is not so simple: if you were to expose every shot in this way, you would have a massive jump in light with every cut, even in a simple shot-counter-shot situation.

Okay, you can hold the shot with the most intense light just before clipping the highlights and shoot the others with the same values – the rest will have to be dealt with in post-production. But if light is to be set or even just a few reflectors are to be used, then professional light measurement becomes very useful. It is just as helpful to be able to use such a device to judge what you need to bring along for good lighting when scouting for locations.

Why only iPhone and iPad here?

Light meter apps for Apple devices have been available for a long time, while the corresponding metadata was not accessible to developers on Android until recently. And then, Android still did not support metadata for colour. However, this is not only necessary for measuring the colour temperature, but also for evaluating the raw data during exposure measurement. Simply analysing the average image data is not enough for this, as the pre-processing of the camera images in the mobile phone distorts the values in an almost unpredictable way: the direct reading of the image data can lead to incorrect measurements of up to two f-stops.

Nevertheless, we also tried out one of the apps tested here, namely myLightMeter Pro, on Android. We used a Motorola Moto E5, which can be considered a very affordable mid-range mobile phone. Not only did it show that the deviation was greater without calibration than with the iPhone. This would not be a problem for an app with calibration, but unfortunately linearity was also significantly worse. This means that after a calibration with medium brightness, the values in dark scenes deviate in one direction and in bright scenes in the other – this is not really useful. The inexhaustible number of such apps for Android and hardware with cameras of varying quality would turn a reasonably representative overview into an encyclopaedia anyway. (What the hell is an encyclopaedia?)

What is a dome?

There are basically two types of light measurement: that of incident light and that of reflected light. Without special accessories, a mobile phone only ever measures the light reflected by the subject, so you are responsible for either measuring on an official grey card (with 18% reflection) or estimating the optimum exposure yourself by measuring highlights and shadows. For professional lighting, on the other hand, it makes much more sense to use a measuring device to determine the incident light. In order to measure more than just the frontal incident light, such a device needs a translucent hemisphere made of neutral white plastic, as in one of our reference devices, the Sekonic.

A Luxi is therefore certainly the most useful addition to the iPhone as a light meter. This is a white hemisphere made of plastic (the dome, see above), which is clipped onto the mobile phone and covers the front camera. The first model of this Kickstarter project is only suitable for some models such as the iPhone 4, 5 and SE and fits them very well. The only disadvantage of the older model is that it only fits properly if the protective cover is removed. The newer version called Luxi For All fits many mobile phone cameras and tablets, seems to be slightly less attenuating and is therefore about half an aperture more sensitive. It is also closer to the characteristics of a conventional light meter in its light distribution when light falls from the side, while the older model is slightly less sensitive to side light. However, you have to position the new Luxi just as precisely, and unfortunately it slips quite easily on the smooth surface of most devices in hectic everyday working life.

The approx. 25 euros charged for this may seem expensive for a simple piece of plastic. However, it was not only used to finance the production, but also the development of the suitable material and the free programme for it, which can also be used as a simple spot meter without the dome. Several of the professional programmes also work with the Luxi as a measuring device for incident light.

This already applies to the inexpensive myLightMeter Pro, and for Pocket Light Meter and Cine Meter II it is almost a matter of course, including a separate calibration. In principle, you can use any app that can be calibrated, because the dome absorbs some light. Just don’t forget to change the calibration again for spot measurement. By the way: The Luxis also fit on an iPod Touch if you don’t want to use your mobile phone. Another alternative to the light meter for those who despise mobile phones.

The candidates

One of our conditions was, of course, that the respective app still runs on the latest version of iOS, and we spared ourselves the trouble of taking our own measurements for apps with obviously devastatingly poor ratings from multiple users. However, the most important criterion for professional use is the ability to calibrate the app using a professional device as a reference. Understandably, the components for mobile phones are not manufactured or selected with the same tight tolerances that apply to a measuring device that costs several hundred euros just for this one task. Deviations are therefore to be expected from such devices without calibration.

Before calibration, our iPhone SE deviated from the average of the reference devices by around 1/3 f-stop, the iPad Pro by a good 2/3. In contrast, another sample of the SE was almost correct even without calibration. After calibrating as carefully as possible, we were particularly interested in the extent to which the devices still matched when the light intensity changed or when the temperature rose. There is a fairly wide selection of apps under iOS, ranging from simple, free programmes to freely available basic versions with advertising disabled or functional enhancements through in-app purchases to purely professional programmes. We have not included apps that first have to take a photo before anything can be measured. We have also not analysed various specialists for pinhole cameras, nighttime or long exposure photography.

How did we measure?

Our reference devices were a Sekonic L-508 Zoom Master, with which both spot metering and incident light metering are possible, and a Minolta Spot F with pure spot metering. Although both devices have been used in everyday shooting for a long time, they only differed by two to three tenths of a f-stop in the medium brightness range, which is quite insignificant. Most apps can only be calibrated in steps of 1/3 aperture, which is completely sufficient in practice – the aperture can hardly be set more precisely even on cinema lenses. Only Cine Meter II allows optional adjustment and display in 1/10 aperture. After adjustment at medium brightness values, both the iPhone SE and the iPad Pro matched the dedicated meters so well over a very wide aperture range that the display in this app did not deviate any further than the meters themselves.

In low light, these somewhat older meters were already “out of range”, while the app still delivered results that seemed plausible in comparison to the very light-sensitive Sony A7S. Similarly, an older iPhone 5 under iOS 9 still delivered precise results even in very bright light. Models such as the SE, which already contains the 6th generation camera, showed a deviation of 2/3 aperture upwards in very bright light. However, this was only the case in direct summer sunlight from behind on a white diffusion screen; the exposure was then around 9 EV above our grey card at medium brightness for the calibration. This phenomenon only affects the newer devices (or their iOS?), and at least Adam Wilt, the developer of Cine Meter II, is already getting to the bottom of this observation.

Some apps also measure the colour temperature. As we didn’t have a spectrometer available for testing – after all, a Sekonic C-700 Spectromaster costs around €1,300 – we compared this display with the measurements of some cameras. When using a Luxi, the measurements for daylight or incandescent light were quite good with a deviation of 200 to 300 K and quite sufficient for determining a suitable filter. With the more critical energy-saving lamps, the precision was worse, and it was also somewhat less accurate using a grey card.

For beginners and free of charge

With Lightmate by Luis Laugga, the easiest to use of the free offers, fans of classic photo cameras can certainly be happy. This is especially true if the in-built light meter has already died or batteries are no longer available. It is clearly laid out, very easy to understand and is capable of spot metering. Simply tap and wait until the metering circle stops flashing. The only disadvantage: as the values are displayed directly in the image, they are more difficult to read in bright areas of the image. Calibration is not possible, so you can only determine the deviation with a reference device and, if necessary, take it into account by setting a different ISO value. Film cameramen will miss the appropriate exposure times, but here the intermediate step of 1/45 second comes quite close to 1/48 or 1/50.

Lux – Professional Light Meter for Film Photography from Avicora allows calibration in 1/3 f-stops via the compensation value and is also quite clear and easy to use. However, contrary to what the name might suggest, it does not recognise the traditional film speed of 24 fps – this refers to analogue film in cameras. It does, however, offer 1/50th of a second or whole-numbered fractions thereof if the “Shutter Stops” setting is set to “Thirds”. This free and ad-free app is therefore also suitable for filmmakers, the only things missing are separate support for a dome, logging and the display of the colour temperature.

Affordable middle class

Light Meter – Street by Oliver Bojahr for 3.49 euros is one of the simplest of the commercially available products. It is based on the measurement of the camera image in the iPhone, but also allows spot measurements by tapping a point in the image. A simple recording button switches between continuous measurement and holding the current measurement. The display is very clear and, after entering the ISO value, you can easily display suitable time/aperture combinations; the last measurement is also saved when you exit the app. As a nice gag, the now almost forgotten mnemonic phrases are displayed in the style of “Sun laughs – aperture eight”. In American, this is called Sunny 16 (de.qwerty.wiki/wiki/Sunny_16_rule) – not because it is brighter there, but because the ISO values are taken into account. The app (as well as an English version) and the operating instructions on Github have been completely Germanised – the author is from here, after all. However, in favour of a quick overview, it only shows whole f-stops or EV values and does not offer any calibration options or film frequencies. On the iPad, the display can be rotated, but the camera image always remains in portrait format. This app is primarily suitable for photographers who are at war with the English language.

Pavel Bukhonov’s Light & Exposure Meter is ad-financed and can do much more. This app is also aimed more at photographers and is available in English and Russian. At least the values can be calibrated, albeit only in steps of 1/3 aperture and not separately for incident light with Luxi. It does not recognise film frequencies, but with 1/45 second you come very close to the standard exposure time. It can also display the colour temperature and log the values, even with thumbnail and location and time information. Unfortunately, you have to interrupt your work to upload or save the individual logs first. The often full-screen and time-controlled adverts for games interrupt your work even more and are extremely annoying if you don’t unlock the app for 5.49 euros. However, some reviews in the App Store suggest that adverts may still be displayed, which would border on fraud. An enquiry to the support address given in the store was unsuccessful, as our emails did not reach them – we therefore decided not to activate the app for testing.

More serious is myLightMeter from David Quiles Amat, which simulates a beautifully designed vintage-style meter in the low-cost version for 2.29 euros (see Android). In the Pro version for 5.99 euros, it can do pretty much everything a photographer could wish for with spot and dome. There are also film frequencies, at least with 1/25, 1/50 etc., and the calibration in the settings is done separately for reflected and incident light (even if only in steps of 1/3 aperture). Separate exposure compensation for subject composition is offered directly in the meter. The app can calculate average values from several measurements, but there is no colour temperature measurement. Unfortunately, there is also no location or time information in the log function, which simply saves an image with exposure values in your own photo album. The “Read File” function allows you to read out the exposure of existing photos from your mobile phone, but without spot metering.

The unique selling point: it displays the hyperfocal distance for the selected aperture, even for infrared photography if required, and you can save up to five presets for your own lenses, taking the sensor size into account. The wealth of functions requires a little more learning, but there is a detailed instruction manual available for download as a PDF (English). The f/tools offered by the same author facilitate numerous photographic calculations, such as aspect ratios, cropping, motion blur, airy disc etc. and are also worth every penny at 1.09 euros. Both apps are obviously real hobby projects of the author and in this price range my recommendation (the Classic version is also available for Android).

The pros

Nuwaste Studios’ Pocket Light Meter, which used to be ad-supported, is now available for €11.99 without adverts. This is the cheapest app that can also display the typical film exposure time of 1/48 second and measure the colour temperature (uncalibrated). The measurement of the incident light can be calibrated in 1/3 f-stops, but unfortunately, despite the support of a Luxi, no separate calibration is offered for this – not an insignificant weakness. In addition, the app deviates a little more from the professional measuring devices than Cine Meter II in very low or very strong light. The greatest positive is the logging, which not only records all measured values, location, time, own notes and the respective image, but can even automatically store this information in a dropbox. With better calibration, this app would be perfect. However, if you only use one of the two measurement types regularly or change the correction value manually, you are already well equipped with this clear and easy-to-use app.

Cine Meter II by Adam Wilt is in the top class. Although it costs 30 euros, it leaves hardly anything to be desired. In addition to all the requirements already mentioned, not only the display but also the calibration can be carried out in 1/10 f-stops. The latter can also be performed separately for the front and rear cameras and separately for Luxi. The measured values are very precise after calibration and can keep up with the dedicated measuring devices (apart from the slight oversensitivity in full sun, which is probably due to the newer Apple hardware, see above). However, an accuracy of a tenth of an aperture is not a decisive criterion in practice, even a third of an aperture is good enough – which lens can be adjusted so precisely?

Cine Meter II can display the colour temperature and the green-magenta shift (also known as Duv) with Luxi or using a grey card from iOS 8, but of course it does not replace a spectrometer, as it is only based on a normal camera with three basic colours. The author explains the problems of such a colour measurement on his website: http://www.adamwilt.com/cinemeterii/colormetering.html (including detailed comparison tables). The calibration of the colour measurement is also described there. Based on this measurement, the app provides filter values for correction to the desired target value. Another typical feature of film is that you can specify a running speed and then set the aperture angle. Since, for aesthetic reasons, you usually don’t want to adjust the aperture or the time when there is too much light on film, you can specify an ND value instead.

While the exposure measurement is very precise, the waveform and false colour display can only be used as relative values because they are influenced by the camera software. This is nevertheless very helpful if, for example, the even illumination of a green screen is to be checked. The only weakness of this app is the logging: the current values are only written to a CSV file at an adjustable interval. You then only have pure lists available, no images and no location information. However, a long press on the displayed image at least generates a screenshot. Nevertheless, logging in the manner of the Pocket Light Meter would be a very helpful further development. The complex yet intuitive user interface is explained with many practical tips on the author’s website, the links can be found directly in the app under “Help”.

Devices with their own electronics

Cine Meter II is the only device (apart from the manufacturer’s app) that also supports the Lumu Lite, including the colour trim function. Lumu is a Kickstarter project from Ljubljana in Slovenia, very nicely packaged with a leather case in black or silver, but unfortunately out of stock by now. It is a much more complex measuring device for incident light with its own sensor and electronics, which in its second incarnation as Lumu Power 2 is only built for Apple devices with a Lightning socket (the manufacturer will have good reasons for this). Unfortunately, the newer version no longer works with Cine Meter II and is available in different versions from 249 to 499 US dollars, taking into account the requirements of film professionals.

Lumu Power is said to be more accurate than its predecessor with a maximum deviation of only 2/10 in lateral light, and it can also capture grazing light from behind, which is shielded by the mobile phone in the Luxi. Users praise the Lumu for better light sensitivity than many expensive light meters and very good temperature compensation. The rotatable dome makes it more flexible in use than the Luxi, and photographers appreciate the measurement of flash units, which an iPhone cannot provide. We have not yet been able to test the device, nor the Illuminati Light Meter. This goes one step further: the electronics are housed in a separate device for 299 US dollars and communicate with the app via Bluetooth. It is therefore independent of the direct connection to a mobile phone or tablet and its operating system or internal hardware.

Comment

Yes, you can use an iPhone as a professional light meter. If you want to keep all your options open, you need the Luxi, Pocket Light Meter for perfect logging and Cine Meter II for very precise measurements and filter determination. That would be around 65 euros, which is still far less than a solid light meter (without the mobile phone, but an old iPhone 4s or 5 will do).

The post The best light meter .. first appeared on DIGITAL PRODUCTION and was written by Uli Plank.

How director Melanie Lopez came up with the idea for “The Stained Club” requires some explanation, as photographs of murder houses provided her with the inspiration: for the “Evidence” project, Angela Strassheim photographed the interiors of American houses where murders had taken place, the blood traces of which were made visible using the chemical compound luminol and UV light. When she saw these photos, Melanie wondered what it would be like if emotional pain left the same indelible marks on people that could not be removed? This was the starting signal for the animated film about Finn and his friends at the beginning of Melanie’s studies in 2014.

However, it was to take a while before the story was ready – the plot was only finalised shortly before Melanie’s final fifth year of study. “I developed the first draft within three months together with my teachers and the team. The story was set in a school at the time and was very basic. Our lecturers were happy with it, but I wasn’t. Fortunately, the summer holidays came and I was able to take some time out from the project. I watched a lot of films during that time to understand what influenced and shaped me as a child. And tada! The knot burst and at the beginning of my final year of study, with Simon Boucly’s help, I changed the entire animatic as well as the set, which became a junkyard,” Melanie recalls.

Finding an end

With the scrapyard as the central location, Melanie found it easier to develop the experiences of the gang of children. In addition, the film “Swiss Army Man”, which was released at the time, motivated Melanie to completely redesign the story, even if it was risky at this point in the production: “‘Swiss Army Man’ seems very far removed from our film at first glance, but it helped the process incredibly. I would have regretted it if I had decided against the changes.” Finding the ending of the film was particularly difficult for Melanie. “I didn’t want to have a specific happy or sad ending to the story, but one that said: this is life – sometimes it’s hard, sometimes it’s happy, but if you keep those close to you close, it definitely gets easier.” As this is not an easy way to end a film, it was a difficult decision for Melanie.

But ultimately, it felt right for the artist to end with Finn’s thoughts and the fact that he feels somewhat alone with the way he lives. But that despite everything, his friends love him and are there for him. “When Robbie throws him the ball, it means he’s forgiven him and they can just move on as if nothing has happened,” Melanie explains. “It’s not really an ending to the storyline, but summarises how Finn has moved on after meeting his friends.”

The storytelling also presented the other team members with major challenges. “We had to make a lot of decisions in order to tell the story in the right way so that it matched Melanie’s intentions. We often put our personal opinions on the back burner, but in the end it turned out to be worth it!” Simon Boucly is certain.

Films as a source of inspiration

One of the most important references for “The Stained Club” were films that show a group of children fighting against something, such as the 80s film “It” by Tommy Lee Wallace or classics like “The Goonies” or “E.T.”. In terms of mood, camera work and lighting, the team orientated themselves on “The Tree of Life” by Terrence Malick and films by Xavier Dolan. Claude Barras’ “My Life as a Courgette” served as a model in terms of the emotional appeal and the portrayal of the protagonists’ childlike innocence. “The film also helped us to understand how we could guide the child actors for the voice recordings,” says Melanie.

Shaping children’s personalities

Right from the start, the director was certain that the children’s characters should have big black eyes. However, Melanie felt that the first draft was too cartoonish. For this reason, the team also tested normal eyes at a certain point during the design process, but the black eyes factor remained important and was implemented in the final film. For the children’s personalities, the team created individual documents in which they recorded preferences, background stories and more. “Even if they don’t appear in the film, it helped with animation and look decisions to make everything coherent and believable,” says Melanie. The students created the children’s characteristics in such a way that each one contributes to the group with their personal strengths and uniqueness. Finn had to be able to admire them for this and want to be a part of it. “The children’s characters include parts of myself as a child as well as characteristics of other people that I admired as a child,” adds Melanie. “Also, the group is mostly boys because they don’t usually show emotional pain and deal with it in a different way than girls. I wanted to show in the film that it’s okay for boys to deal with their feelings too.”

The team shot reference videos with the actor Robert Bennet, which helped a lot with the animation process because he gave the team a lot of ideas with his acting. Simon’s favourite part of the animation work was shaping the children’s personalities through their behaviour in their games, while keeping in mind what they had already been through.

This hardship in the children’s lives is particularly evident in one scene in the film, which Alice Jaunet particularly appreciates due to its subtle narrative style: “The way Finn’s mother rejects him is the emotional highlight of the film for me. No matter how many times I watch the film, it feels like a punch in the gut every time. Beatrice did a great job with the FX on this one.”

Explain how much?

The team realised the Previs animatic in Maya. They initially edited with Premiere because the software was more efficient to work with during the test phase. However, as the process progressed, the team switched to Avid Media Composer, which the students also used for the final editing. During the previs phase, which lasted six months, 30 versions of the film were created. “In order to achieve the emotions we wanted, it took a lot of test runs and discussions,” recalls Simon. “It caused us a lot of problems until we knew how much we had to explain so that the emotions of the film could be felt by the audience. We realised that the more we explained, the less empathy there was for the characters. A concrete example of this is Finn’s magic marks. Although they repeatedly have a meaning throughout the story, the film never explains exactly what they actually are. The audience has to find their own explanation. This involves them in the plot.” For Melanie, this openness of interpretation is an important factor in the finished film: “Some people see the stains as a general means of talking about otherness. One grandmother told me after the film that they represent handicaps in general for her. That really touched me, because it showed me that the film can be interpreted according to a person’s personal situation and that we had chosen the right path.”

Too long arms and other design challenges

Based on the 2D designs of the characters that Melanie created, the students modelled the 3D characters in Maya. Melanie checked that the look was going in the right direction from an artistic point of view, while Simon checked that the design would work in animation.

Between design and rigging, the process went back and forth a lot until they were sure that the characters with the big head were animatable. “Translating the 2D design into 3D was complicated, and Finn in particular was a challenge. In the animatic, we already recognised the problem with his design: his arms were far too short. We had to make numerous adjustments until his proportions were right for the animation, the story and the VFX,” explains Simon. The characters’ movements had to remain subtle, so it wasn’t so easy to convey the emotions through the animation. “Every detail counted,” says animation artist Chan Stephie Peang. “In particular, animating Robbie in the trolley scene feeling like a superhero with his cape blowing in the wind was a lot of fun.”

The characters’ hair was created in ZBrush, with Alice doing the sculpting and Marie Ciesielski retopologising to light the meshes afterwards. “We decided not to simulate the hair, but to create it with stylised sculpted plates instead,” says Alice. “They had to match the overall style of the film, but at the same time not be too complicated to animate. Marie luckily helped me with the last bit of the challenging task.”

The team put a lot of work into the skin of the child protagonists in particular. Melanie explains why: “It should feel like you could touch them for the audience.” The students realised them with the Substance Painter, which they had recently got to know. Substance Painter was the most useful and practical software for realistic texturing in combination with digital painting. The artists needed this feature to place the children’s drawings on the 3D objects.

Goal: High contrast and not perfect

The background needed to contrast with the cartoonish look of the characters, which is why the team chose a realistic approach. For the stylised look, the students looked at stop-motion references such as those from “ParaNorman”. “The contrast between the cute faces and the harsh environment is meant to symbolise how harsh the world can sometimes be to children,” says Melanie. As much of the action takes place outdoors, numerous sky sets with different times of day and lighting moods had to be created. The team sourced high-res images from the Unsplash website. The students modified these in Photoshop by removing trees and other objects and then integrated them into cards in Nuke.

Realistic scheduling

As the bar was set high for the project, good time management was crucial: a teacher helped to plan the tasks and shots at the beginning. The team used Google Sheets to organise the project, in which all team members updated the status of each task. Beatrice took over the time planning part: “After the 3D animatic was finished, I estimated how long it would take to create all the assets and how much time the individual work steps such as animation, lighting or compositing would take for each individual shot.” With the help of a Gantt chart, the student then produced an estimate of the working days per person that was as accurate as possible. “I made a monthly daily business plan for the team, so I was able to make a realistic estimate of the workload for the rest of the year using real working hours for the tasks.”

In a perfect project world

If Melanie could make the film again, in an ideal project world without time pressure, she would give the actors more time for the live references so that they could create the scenes more freely and not have to act out the script so strictly. “But we didn’t have enough actors or enough time for that,” regrets Melanie. “I would also find every conceivable trick in 3D so that the characters could stay close to the 2D design. We had to change a lot of the design so that the rigs worked and the clothes weren’t too much of a burden during production. I would have liked to have had more time to realise everything as planned and not have it taken away by the technology. But that would only have been possible in a perfect world. We did everything we could for ‘The Stained Club’ within the time frame, which I’m very proud of.”

The post Finns Fleckengang: The Stained Club first appeared on DIGITAL PRODUCTION and was written by Mirja Fürst.