Creative and business resources for photographers – ProPhotoNut

Fresnel lensed lights – retro portraits

August 30th, 2008

From time to time a new technology emerges that changes the way I light or shoot. I seem to be on this ever progressing conveyor. A photographic journey fueled by the endless supply of new bigger, better, more sensitive cameras. However it pays to look back from time to time. This is my recent shoot with the wonderful Fresnel lens spotlights of the motion picture industry.

Several generations after the development of studio flash lighting, using tungsten lights to make portraits seems so yesteryear. However the film and TV industry hasn’t ever let go of the one bit of lighting kit it thrives on. The Fresnel lensed spotlights that grace every set make excellent lights for taking still pictures too. Now that digital camera sensitivity has caught up with film and 400 ISO is completely usable an exposure of f4 at 1/60th is easily achievable with low wattage tungsten lights.

When I shot TV at the BBC we used f4 continuously when shooting drama and we lit our sets to 800 lux. We mainly used Fresnel spotlights with a few soft sources to provide shadow fill and contrast control. It was easy to take the luminaries for granted but the light they produce has a wonderful quality that has ensured they will never become obsolete.

I decided to rekindle my passion for lighting people with this unique hard light and I bought a pair of Arri 300 Junior fresnel spotlights on EBAY. Buying Arri lighting equipment second hand is a safe bet because of the excellent build quality of all TV and motion picture kit.

The fresnel lens is like that used in a lighthouse. It is made of concentric rings of glass with increasing angles near the outside. This gives the power of a very thick lens without the bulk of glass required. The lamp side of the lens has a slight dimpled surface to scatter any chromatic aberration.

The look of the light it produces is one of beautifully smooth transitions from the hot spot to the unlit zone. The bulb is moved forwards and backwards inside the lamp housing to create a flood or spot effect. On full flood the light emits an even illumination level over an angle of 60 degrees and then a smooth transition to unlit. In this mode the barn doors on the light can be used to shape the pattern of light produced as a flooded light is a hard light source. Virtually all of the lights in a TV studio will be set to full flood. The shape the barn doors are set to suit the shot and the barn door configurations have their own names like ‘boxed square’, ‘Chinese letterbox’ ‘English letterbox’ and ‘slash’ etc.

On full spot the light pattern created by the lens is a tight spot of light that goes from unlit to fully lit and back again in a beautifully smooth sine wave style. In this mode the barn doors only attenuate the light and cannot be used to create light shaping. This full spot mode gives softer shadows and more light intensity in the hot spot. It is most often used in theaters and when trying to create a ‘snooted’ look.

One small lamp can be used in so many ways and because it is a continuous light source what you see is what you get. There is a magic romantic feel to images taken with Fresnel lights. It’s sound equivalent would be an old valve radio that has a warm rounded timbre.

Tungsten lights have a nominal colour temperature of 3200k although it is rare to get more than 3000 out of a partly used bulb. In the TV studio we would set the colour temperature to 2950k and line up at that colour. With digital stills and RAW shooting I suggest you set the white balance to the factory set tungsten setting and make any final tweaks in post production.

If you are mixing daylight with tungsten lighting then you need to use colour correction gel on the lights or use HMI versions of the Fresnel lights. HMI lights are bluer and approximate to the colour temperature of daylight. They give a far higher level of light for a given wattage but require a separate ballast in order to work. I always use half blue Lee 202 gel to correct my tungsten lights. As it is only half blue, I often need to double it up to get to daylight or 5600k. For portraiture one layer of 202 is usually perfect giving a warm flattering look and by correcting for it in post production the ambient daylight takes on a subtle cool blue that I love.

I used one Arri as a key light and one as a back light. Occasionally I used a third tungsten light as a kicker or a second backlight. The main objective is to set the key or principal light first. Set it too steep and eye sockets become black holes, too shallow and the subject looks as though they have come straight out of a horror movie. A lot of the images were taken with the key light ‘upstage’ that is, leaving the shadowed side of the face towards the camera. I like the angle set so that the tip of the nose shadow touches the cheek shadow and leaves a triangle of light nearest the camera.

Once the key light is set I always add a backlight beyond the subject looking straight back towards the camera. Barn doors and lens hoods are needed to avoid flare.

Finally I add a background light to help with the separation of tones. This can be a slash or a spot depending upon the retro era. A reflector can be used to lift the shadows out of the noise zone. The shadows can then be darkened later in Lightroom. This ensures wonderfully clean shadow detail and files that are a joy to print.