Weight vs quality?
At the end of the summer at the IBC in Amsterdam, a representative from the German company Sumolight asked the “FilmPro” magazine to test of their LED lamp. The reason for their interest was the “LED Lamp Test” in our magazine (number 1(29)2017). They wanted to face the best on the Polish market. So we are introducing our Sumolight lamp test.
We used two Dedolite DLH4-3200 K lamps as our primary reference light source. These are the most popular, with a TCLI index of 100. From the other side – We have used Panasonic Varicam 35 camera, the true winner of the big camera tests we did two years ago. (Panasonic wins for its color reproduction and the effective tonal range. For the purpose of our test we used a top-of-the-line camera lens, the Zeiss Master Prime 85mm, T1.3, and for obvious reasons – the DSC Labs ChromaDuMonde 24 + 4 color chart – already known as ultimate color test chart.
From every time the 3200 K and 5600 K reference lights were changed to the 3200 K and 5600 K LEDs, the white balance was used to eliminate the drift of the color temperature towards the green or purple in the vector image. As a result, we do not have any white shifts, and the whole process gives a more consistent picture. The LED was aligned to 3200 and 5600 using a UPRtek spectrophotometer with a calibrated precision of a few Kelvin. In other words – very accurately.
From the whole test, I can basically present only one comparative vector diagram, because all others are simply identical. Which means nothing other than the absence of any changes in the color representation of the LED light. Regardless of the color temperature – either 3200 or 5600 K at this time. If you look at the diagram – you can clearly see what I mean: this diagram really shows the TWO sets of vector images. I was surprised.
During testing the other lamps at the beginning of this year, I understood that the LEDs from Akurat and Dedolight were perfect. Today I can say that none of the previously tested LEDs behaved as super-fine as the SUMOSPACE Bi-color 500 W. The very smooth adjustment of the color temperature the SUMOSPACE is within the range of 2800 K – 6500 K. During the color temperature change, the light intensity remains constant. In his technical info – the manufacturer showed the real power of the lamp, not the sum, which is the common approach on the market used to hide some inconsistency. In other words – nothing fades!
The color rendering index given by the manufacturer is CRI Ra = 95, TLCI = 99.
My measurements for 3200 K light are CRI Ra = 95 R13 and R15 = 94, TLCI = 93.5.
Measurements for light 5600 K CRI Ra = 94 R13 and 15 = 96 TLCI = 97.3
It is worth recalling that R13 is a mapping of Caucasian skin color and R15 is Asian. The SumoSpace Bi-color 500 W unit can be a source of direct and diffused light. The “naked” lamp emits light very wide, at a 120-degree angle. Light intensity obtained at the same distances is twice as high as that obtained with the Arri Skypanel 60 / 400 W working an angle of 110 degrees. I do not know how Sumolight does it. But this is the result of the test. The efficiency of SUMOSPACE, I must say just one word – respect.
Sumolight supplies a yoke that allows you to combine seven lamps into one honeycomb lighting panel (a fairly large patch) with a luminescence area of about 1.5 m in diameter and a total power of 3500 W LEDs, giving us a unit comparable to the 18 KW HMI when we put the 30-degree lens on the lamps. Yes, it’s not a mistake. This corresponds to what we get using the 18 KW lamp.
The single unit can be easily adapted to a diffused light and the diffuser is 90 cm in diameter. When we put a sleeve on the fabric between the diffuser and the apron, we get a space light (1200) HMI unit.
The word SUMO in the name does not correlate to the weight of this unit, but rather the light power. The weight of this lamp is only 5.5 kg. Compared to other 400W LEDs, it is a featherweight. All the other panels that have taken part in our big lamp test are rather heavy – in the range of 15-25 kg.
The cooling system of this lamp is passively cooled, which means – no fans. And the presence of fans in the case of typical LED lamps, as we know – increases the noise level, which is, of course, bad for the sound. In the case of Sumo – sound guys will love it.
The Sumo units can be controlled by all existing communication systems ie WiFi, DMX, etc. SUMOSAPCE is designed in a way that it can be transported as a “stack” – like fruit boxes. Special transport packages are not needed for every single lamp in this case. Bi-color lamp in terms of weight, light efficiency and versatility is the most attractive price on the market. And it’s not PR. It’s just like that. Period.
The laws of physics regarding light have not changed for the time being. And they will not change in the near future. We all know that the intensity of light is dependent on the square of the distance, or square of the surface area to which the luminous flux is active, which in our practice is connected basically with the root of two. In this case, the change in luminosity is twofold.
And maybe it would force the manufacturers in the case of LEDs to provide us with the light intensity of a given unit in a particular way. For example, using data are taken from the fourth meter and fixed the angle of light stream, ie. 40-degrees? This type of parameter will give us a uniform comparison to all lights. (If a lamp works only using specific angle – i.e. 110 or 80-degrees, the manufacturer should convert its data to match values “pretending” that lamp uses mentioned 40-degrees.) For us, every change in the distance or angle of light using square of two means that it is twice brighter or twice darker.
Camerimage festival starts soon. Many manufacturers will attend as well as cinematographers. This is the place where you can initiate a discussion about new scale usage for lamps that will allow us to calculate or understand everything about lamps in a very simple way. Regardless of the manufacturer. This approach can help not only users but manufacturers as well. We will finally see what they really did. And there will be no BS. It is also about the reliability of the manufacturers and their products.
For years, we have used the Exposure Value scale to determine the exposure. EV = 0 calculated from 1 Lux x 1 second x 100 ISO. Thus, by the same token, it would be possible to establish a scale called, for example, LUX VALUE, based on proportionality, where the starting point of the comparative light intensity would be, for example, already mentioned fourth meter and the angle of 40-degrees. why not?
Let’s go back to the photometric measurements of the SUMOSPACE Bi-color 500 W using UPRtek CV 600 spectrophotometer (which adds a few useful features to the Seconik C-700 btw). When measuring color temperature, we can read additional information about CRI and TLCI. We can read as well where the white point is situated or any specific color – on the CIE chromaticity charts 1931 and 1976.
When the CRI of the measured light is 100, and we personally find that something is wrong with the perceived color, or – totally opposite – when CRI is 20, and we are saying: “Wow, what great colors”, this means that we should immediately go to the doctors of many medical specializations.
TLCI – The Television Lighting Consistency Index is an indicator of how color fidelity will be recorded when using a given light source on a 0-100 scale. When the TLCI index is less than 50, it means that we will have big problems with color reproduction, even during color grading process.
A few words about the tools we used during the tests. In the diagrams below we can check the parameters of the Sumo lamps. The screenshots are related to the SUMOSPACE Bi-color 500W measurements using a spectrophotometer. Everything should be legible. The second important function that the spectrophotometer offers is the possibility to test the possible pulsations of the lamps according to what is set in the parameters of the camera. The spectrophotometer will show us the correct settings for the sector at a given frame so that the image does not flicker. The film world is on the one hand very open, and from the other side – quite “closed” – not willing to change too much. Open to new ideas, unusual visual solutions, crazy things that change our perception of the cinema, but still quite conservative, when it comes to light. The point is, that the changes in technology are happening quite fast and the cinematographers cannot always keep up with what is happening in the market. This is because they usually use proven and therefore secure solutions, and they are little suspicious when it comes to new, not widely popular lighting units; new types of lights, etc.
Sumolight as a novum can be doomed to a slow “appearance” in the minds of cinematographers, but if Sumolight appears in their hands – or you may say in that specific “sumo ring” – it will be very difficult to throw it out. Like with real sumo fighters.