Photographing indoors meant, until recently, changing the White Balance in your digital camera to Tungsten. With incandescent light bulbs going the way of the dodo, things are not always easy. Some of the cheap LED (Light Emitting Diode) light bulbs available in the market may give you a whole rainbow of colours during their lifetime, instead of the “white” your eyes seem to see there. Your camera sees differently, you see!
We’re not talking about calibrated LED panels—and even some of the cheaper ones will not offer faithful colour—but common LED light bulbs that are being used nowadays. They represent, for some photographic work, a good option in terms of light, but users have to understand what they can expect in terms of colour, and investigate in their own market which brands work the best.
Use With Any Light You Like
With digital cameras and a digital world, we’re spoilt for choice when it comes to light. Small and big LED lights have changed the way we photograph. While with film cameras the emulsions were bought for a specific type of light and then converted to another through the use of filters, if needed, with digital cameras the White Balance can be set for specific situations—Sun, Shadow, Cloudy, Tungsten, Fluorescent, Flash, etc.—and adjusted, in some of them, manually, from values, for example, between 2,000 and 10,000 Kelvin.
This means it is possible, at least in theory, to use any type of light for photography, and still get results that keep the colours close to the original. But for this to happen, it is necessary to know the temperature of the light you’re using. Those shooting RAW can always argue that adjustments can be done in post-processing, but they should remember that the image presented on the camera LCD is a JPEG, so having chosen a colour temperature close to the source of light used will help to check how everything looks in the photograph. It will also reduce time in front of the computer adjusting settings in the end, something most photographers will prefer.
With so many types of light available today, it can be difficult to choose which one to use. Before, for people using available light inside houses, it was an easy choice. Tungsten incandescent bulbs used to be a common household light, so emulsions for tungsten (which was also used as continuous light in many photographic studios) were bought to be used indoors. With a digital camera, simply adjusting the setting for tungsten light corrects the excessive orange cast, introducing blue (with film, users would need to attach a blue conversion filter in front of the lens). But tungsten is less common these days, as people are eschewing them for lights that can help, theoretically, to reduce costs and our carbon footprint. That’s why so many different light bulbs with LEDs are available in the market today.
In fact, the normal 40 and 60 watt incandescent bulbs are being phased out and are already banned in multiple countries. Other types of lighting, like Compact Fluorescent Lamps (CFL), also called energy-saving lights, took their place, but as the price for LED lights, which are superior in terms of energy-saving, came down, LED lights are rapidly being adopted and will become mainstream as a replacement for the old incandescent bulbs. This means photographers now have to learn to live and photograph under these lights. And there are multiple reasons to want to do it.
Choose Your LEDs Wisely
LED bulbs offer the same light as tungsten bulbs, but cost less, as they need less energy. Although the initial price is higher, even if prices are going down quickly, the investment pays off in the long term. LED lights are also easier to work with because they do not get as warm as the tungsten lights previously used in studios. In fact, LEDs are more efficient: while 90% of the energy consumed by an incandescent light bulb is radiated as heat, rather than visible light, less than 10% of the energy consumed by an LED is emitted as heat. They are less prone to be the origin of a fire and do not burn if touched, as tungsten lights do.
One thing to look for when moving on to LED lights is their equivalent wattage power. There is a misconception that LED lights have less power, because they have less watts, but that’s wrong. All LED bulbs have a “real wattage” and an “equivalent wattage” indicated in the package. The real wattage indicates the actual amount of power the LED uses, while the equivalent wattage indicates the power of the bulb related to the lamps we’re used to. For example, a 5W LED has an equivalent wattage of 30 watts. This means that using them in your photo studio will be less expensive, but you still get the same light as a 30W incandescent light bulb.
The wattage should be the first thing to look for when buying a LED light to replace tungsten, so you get the power you need. The second thing to look for is the colour temperature of the LED bulb, which is measured in Kelvin. Light with a low Kelvin rating, 3,500K or less, is referred to as "warm" light and has a soft, yellowy-orange glow. Light with a high Kelvin rating, 6,000K or more, is "cool" and has a blueish white quality. This value is usually indicated in the package and in the bulb itself. LEDs usually come in two types: warm and cool light. The current standard for the LED lighting industry is warm white (3,000K) and cool white (6,000K).One of the lights tested for this article, the Luxman 5W, has a temperature of 4,000K, producing light that is less warm than the Philips 4W model tested, which has 3,000K.
Lumens, CRI, and the Others
Recently, a new unit has been used to measure the light emitted by a lamp: lumens. While Watts measure the amount of energy required, Lumens measure the amount of light produced. It is really simple: the more lumens a light offers, the brighter it is. This information is now mandatory in packages, but there is something people should know: Lumens are not the same for everybody. In fact, due to the differences in voltage, 800 lumens means a 60W bulb in the USA, while in countries with a higher voltage grid. 700 lumens equals 60W.
When buying new lights, the other element you’re told to look for if you’re after colour fidelity, as may be the case in photography and video, is the CRI (Colour Rendering Index) of the LED bulb, a value that, unfortunately, many companies omit. The CRI measures the ability of a light source to reproduce colours faithfully, when compared to a natural light source. The reference value for CRI is 100.
This is where LEDs have, somehow, a difficult time. Most LEDs have a CRI between 80 to 90, with some manufacturers claiming higher values, but this is an area where the old incandescent light bulbs still do better. In fact, although they're inefficient, incandescent light bulbs offer a CRI of 100, because the light emitted from the filament inside the bulb yields near-perfect color rendition. This makes them naturally suitable for photography and cinematography.
Nevertheless, CRI is a measurement not widely accepted when it comes to LED light bulbs, as it is a poor indicator of the perception of light produced by LEDs. For example, some LEDs with a CRI as low as 25 can produce white light that actually makes object colors appear more vivid, while LEDS with high CRI scores render some saturated object colors, particularly red, very poorly (read the article Is Color Quality Scale (CQS) an improvement on CRI?)
Aware of the problems CRI faces, CIE (International Commission on Illumination, also known as the CIE from its French title, the Commission Internationale de l'Eclairage) established a technical committee in 2006 to develop and recommend a new color rendering metric. Although a Color Quality Scale (CQS) was developed and presented, in 2010, by the U.S. National Institute of Standards and Technology (NIST), no agreement about the new definition has been reached, meaning CRI is still used as a reference.
Used for more than four decades, created to indicate how colors appear under different light sources, particularly fluorescent and high-intensity discharge lamps, and to best correspond them to a human’s perception of color quality, the CRI may, in fact, not be the best choice for modern technology, both in terms of lighting and light capture devices. Sensors from digital cameras react differently from emulsions, and the lights used in modern days represent a challenge to the system.
LED Lights, Motion Film, and Television
Tests produced by the Academy of Motion Picture Arts and Sciences revealed that there are problems with the use of LED lights in motion film. Furthermore, the website of The Guild of Television Cameramen has an article by Alan Roberts which explains the advantages of TLCI (Television Lighting Consistency Index) over CRI. The author states that: “The CRI (Color Rendering Index) has many flaws and is unreliable even when used for its original intended purpose, assessing lighting for industrial and architectural situations. It is even less meaningful if used in a television environment. Even CCT (Correlated Colour Temperature) meters are misleading and inaccurate if used with fluorescent or LED light sources. The solution is the TLCI (Television Lighting Consistency Index) which, although not an approved international standard, is recommended by the EBU and is finding success among manufacturers.”
The TLCI and the Color Quality Scale (CQS) are not the only aspiring standard available today. There are multiple suggestions of systems to substitute the measurement system from CIE. But for the time being, whether we like it or not—and whether we use it or not—CRI seems to be the reference word people still look for when thinking about LED lights. The truth is that many manufacturers, especially of household LED light bulbs, seem to omit it. Still, the presence of wattage and colour temperature seem to be, for most purposes, a good starting point to choose your LEDs. Not professional looking LED lights, but the simple light bulbs used at home.
Either for video or photography, these light bulbs can be your friends. But you have to choose wisely to get the best experience, both regarding home illumination and the uses in photography and video. As with everything else, there can be poor quality and high quality LED lamps. Do not buy LED light bulbs simply based on their cheap price.
LEDs That Look Like Tungsten Bulbs
LED light bulbs have taken different shapes through their lifetime, from the “spot” like appearance to a more conventional look, that makes them similar to the A19 incandescent light bulbs that have been the standard for household lighting. There is one evident advantage of the bulb shaped form factor: the light is omni-directional. That’s the reason why manufacturers are offering LED light bulbs that try to emulate the traditional shape.
The Philips SlimStyle series is an example of a dimmable LED bulb which is the same size as a traditional A19 light bulb but in a new, modern design, a flat appearance that was built to be omni-directional like an incandescent light. This bulb can replace a 40 or 60W incandescent and it’s available in Daylight (5000K) or Soft White (2700K).
Using LEDs for photography and video does not have to be complicated. The best way to start doing it is to check which type of LEDs you have available, when it comes to colour temperature, and to confirm that they give you the light you need. Afterwards it is just a matter of adjusting the colour temperature in your camera and checking the results in the LCD. For this article I used lights from Philips and Luxman, commercially available, with the results shown in the images published. Check the options in your region’s market. This article should help you to get started.
From the tests I made, it is easy to understand that the best results are achieved using the exact colour temperature or the one closest to it. Adjusting the Kelvin scale in your camera is the best way to obtain the most colour fidelity, as suggested by the tests. The Automatic White Balance (AWB) does not seem to work, although if you’re using mixed types of lighting it may be your best option. Still, the best thing to do is to make tests and check the results. With LiveView active it is possible to have instant feedback, and define the best choices for a capture that offers the best colour fidelity.
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