Mixing UV and white light sources

We have been exploring the possibility of creating new lighting effects by using daylight-balanced and UV light sources simultaneously. The two light sources produce inherently different effects, which can conflict with each other and detract from the overall image. At the same time, new possibilities are opened by breaking the conventional rules of thumb. Often, these new approaches are discovered by playful experimenting on the set, rather than by pre-planning the shoot.

Here is my recent blog post about this for The Black Light Magazine.

AA5Q9011_08-10-2016UV light photography is typically done in a dark studio and, until recently, with a relatively long shutter speed to maximize the intensity of the fluorescent light. As a result, “black light” photographs have a distinct look that features high tonal and colour contrast, a black background and a distinct bluish-purple colour cast produced by the visible portion of the LED or strobe lights.

We have been experimenting with mixing the visible, white light sources with UV strobes in order to expand the range of types of images that can be obtained using UV light and fluorescent paint. In the process, we have come across several technical and creative issues that shape the concepts that lend themselves well to UV photography.

First, when daylight-balanced light is used in conjunction with a source that is strongly biased towards the violet and ultra-violet side of the spectrum, managing the resulting colour cast, i.e. setting the white point correctly, becomes a challenge not only in the camera settings, but also in post-processing. This technical issue can be overcome relatively easily by using coloured gels on top of the UV-filtered strobes. The only drawback of this approach is that the gels further limit the intensity of the light, which has already been greatly reduced by the UV filters.

The second issue with mixing the UV and visible light is more conceptual, and it has to do with the type of image that can be created. Considering a portrait of a model with fluorescent makeup, for example, we quickly discovered that as we made the relative contrition of conventional, daylight-balanced strobes more prominent, the portrait became more and more, well.., conventional. This happened because the distinct colours and contrast of the fluorescent makeup became less prominent and significant in the overall image.

AA5Q8950_08-10-2016In order to maintain the impart of the fluorescent makeup, we found that it is effective to break the conventional rules of lighting the model. Specifically, instead of diffusing the incident light, we used a small, directed light source that created harsh shadows on the model’s face, i.e. sharp transitions between the light and the dark areas. This way, the fluorescent makeup, which was located in the deep shadows, was not affected by the white light and was very prominent in the resulting image.

In conventional portrait photography, particularly in “beauty” portraits, harsh light is avoided as being unflattering to the model. However, when the creative process features unconventional techniques like UV light and fluorescent paints, the solution to arising conceptual problems often lies at the extremes, or even is the exact opposite, of established guidelines. In this respect, the creative process is similar to scientific discovery, where researchers are advised to look for new insights at the fringes of the explored areas.

AA5Q9054_08-10-2016

Under and over the water

AA5Q5295_07-12-2016

Here is a post for The Black Light Magazine on a photoshoot, where I was not involved as a photographer. In fact, the most challenging part for the production planning, and I avoided even most of that, being on travel in The Netherlands. Moving into the area of technically challenging shoots, where we have to rely on other people (e.g. a diver in this case) to press the trigger for me and my associates. One aspect that I am still trying to reconcile is the apparent lack of creative control that comes with delegating the actual shooting part. Perhaps, this is the inherent difference between the skills and the vision of the camera operator and the director. I should start looking at the shoot from the director’s chair and learn to enjoy the view.

—-

During a recent underwater photoshoot, which involved a marathon body-painting session by three artists working simultaneously on two models and a diver sitting on the bottom of the pool with the gear that is typically used for photographing marine creatures, we came across a rather unique challenge. Our objective was to show the models in fluorescent makeup swimming underwater, while simultaneously showing their environment, i.e. the reflections of the free surface and the colour of the water itself.

Capturing the images of the models was relatively straightforward. They were illuminated with underwater strobes cover with custom UV filters. “Straightforward” doesn’t mean “trivial”, though. The diver-photographer actually to shed some blood by cutting his finger on the edge of the filter. Luckily, there were no no bloodthirsty creatures in the pool…

AA5Q5414_07-12-2016

The challenge was to simultaneously illuminate the environment (i.e. the water) with studio strobes placed at the edge pf the pool. Since they were positioned above the surface, they could not be triggered with a radio trigger on the diver’s camera, since the triggering signal does not travel well under water. A makeshift solution was to stick one of the underwater flashes over the surface and trigger the studio strobes optically. The major drawback of this approach is that it significantly reduced the already scarce amount of light available underwater for illuminating the models.

A modified triggering method, that we are going to thoroughly test in a follow up photo shoot will involve floating a wireless trigger, coupled with an optical sensor, in a sealed glass container on the surface of the pool, giving it access to both the underwater flashes (optically) and the above-water studio strobes (via radio).

AA5Q5475_07-12-2016

How to photograph people in glasses

More photos here: http://ow.ly/JmLqn

As I was taking headshots of colleagues from the mathematics department for their website (in case it is not obvious, the photos in this post are not of them), couple of things became apparent: (a) many math professors wear glasses; and (b) glasses are a big part of people’s image, and they are attached to them. From the photography standpoint, glasses are problematic because they reflect light and produce glare, which obstructs the eyes.

In most cases, if at all possible, it is better to remove the glasses and take a portrait without them.

However, if removing the glasses is not desirable (see observation (b) above), it is useful to take into account the direction of the dominant light source. Specifically, it is easier to avoid the reflections in eyeglasses, is the subject is illuminated by broad lighting, where the most illuminated side of the face is the closest to the camera. In this case, the subject is facing away from the dominant light source, so the reflections of this light source are directed away from the camera. Broad lighting is the opposite of short lighting, where the most illuminated side of the face is farthest from the camera. It is more difficult to avoid the glare in eyeglasses in the case of short lighting.

AA5Q2459_04-11-2015.jpg

Contre-jour

AA5Q2566_02-15-2015.jpg

Shooting with the lens pointed into the light source (contre-jour), which produces backlighting of the subject is very effective when the light source is the bright sun. Contre-jour is an alternative to front lighting, which can be extremely contrasty (image above).

Today, during and afternoon soccer game, the bright sun produced a huge dynamic range, which was way beyond the capabilities of a DSLR. To experiment with different lighting, I shot half of the game with frontal lighting and the second half – with backlighting (image below). As expected, the latter images were generally more interesting. I particularly like the edge lighting effect, which is mostly noticeable along the hairlines of the players. By the way, a side note for image conscious soccer players – the photographic appeal of an action portrait is directly proportional to the length of the hairdo.

Shooting against the sun doesn’t solve the problem of the large dynamic range, it just distributes the light (or rather the shadow) uniformly across the subject. The contrast is reduced dramatically, but can be partially recovered in post-processing. Lack of contrast also makes the focus more difficult to achieve; I missed more shots due to autofocus failure than I expected. Overall, my preference for shooting sports in bright sunlight would still be centre-jour, even just for the aesthetics of the edge light.

AA5Q3881_02-15-2015.jpg

Light modifiers: a matter of size

PO-IMG_4540_04-04-13.jpg

The main parameter in choosing light modifiers (soft boxes or umbrellas, for example) for studio strbes is the size of the modifiers. Generally for portraits, the larger the modifiers, the better. The main function of soft boxes and umbrellas is to change a small light source into a large one. This creates soft, gradual transitions between the light and dark areas on the subject, which is aesthetically pleasing for most portraits (or course, there are situations, when the rules are broken intentionally to create impact, but that is another story). In my opinion, the more the light source resembles natural window light, the better. This concerns the size of the light source, its position (height relative to the subject) and its colour temperature.

There is not a huge difference between brand name and generic soft boxes and umbrellas in terms of the quality of light, so I think it is safe to use cheaper modifiers without sacrificing the quality of the resulting photo.

A disadvantage of very large soft boxes or umbrellas is that they are very cumbersome to use outdoors. They are, essentially, sails that catch every slightest gust of wind and tend to topple over, unless the stands are weighted down with sand bags. For an outdoor shoot, I use Speedlites, preferably off-camera, triggered by a PocketWizard radio triggers.

I found that getting started with studio lights is a bit intimidating, because of the many changes in the workflow, compared to a natural light setting. The best way to start is to assist someone who knows what he/she is doing and later copy the basic setup (there is nothing complicated about it, after all). The lighting principles themselves are actually quite straightforward, and another way to approach studio lighting is to read a  book, such as “Light It, Shoot It, Retouch It.”

5DM2_MG_9075_03-10-12-Edit.jpg

In the dance studio

AA5Q5385_12-13-2014-Edit.jpg

Today, I took photos in a children’s dance school, not as part of a pro photo shoot, but being a spectator in a class. I did not use any flashes – just a 70-200mm f/2.8L IS lens on a Canon EOS-1D X body. I shot at f/2.8 and auto ISO, varying the shutter speed between 1/200 sec and 1/800 sec, depending on how fast the children (3-5 year old girls) moved.

It turned out that motion blur was not the problem (the girls were not vary fast at that age), but the flickering fluorescent light caused all sorts of weird colour casts. The light tubes were not only quite dim – they flickered between pinkish and greenish colours. To make matters worse, different light tubes in the studio flickered with different phase relative to each other, so in some of my images, part of the frame had pink cast and another part – green.

Normally, I would correct the colour in post-processing, aiming to create realistic skin tone. However, with colour gradients across the frame, often the only option was to convert the photo to black-and-white. Still, today’s shoot was the case where being spontaneous and unobtrusive mattered more than creating high-quality lighting conditions.

AA5Q4839_12-13-2014-Edit.jpg

Black background: controlling the light

AA5Q0961_11-15-2014-BW.jpg

The dance studio photoshoot this weekend took place in a large room with a black curtain on the back. Armando and I set up four strobes surrounding the subjects (a group of children), and another strobe fitted with a large softbox directly in front and overhead of the subjects, as the key light. Even though the background curtain was black, it did have folds, wrinkles, etc., so it was important to make sure that no light fell on it in order for the background to come out completely black. I set my Canon EOS-1D X in manual mode with ISO 100, f/10 and 1/200 sec, so that ambient light was not registering at all. In order to avoid spilling the light on the background, we turned the two strobes located closest to it away from the curtain, so that they faced the camera and illuminated the subjects from behind. We used parabolic reflectors with honeycomb grids on these strobes to focus their beams.

The other strobes were turned towards the background, so to avoid illuminating it, we took advantage of the large size of the room and positioned the subjects sufficiently far from the background, so that the light from the strobes would fall off and would not reach the curtain. To have more control of the light direction, we put strip banks (a rectangular grids on soft vanes) on the front to the softboxes. This way, all the lights coming from the front were soft, but still relatively focussed.

AA5Q1013_11-15-2014-BW.jpg

One surprising feature of the dance floor, which is basically a matt black material with a texture somewhere between plastic and rubber, is that it is not so matt, but rather quite reflective under the strobe lights. We did not want the light themselves reflecting in the floor, so we tilted the softboxes  slightly upward. The reflections of the subjects, on the other hand, looked very nice, and I tried to make them part of the composition whenever possible.

The floor was also scuffed everywhere by the dancers’ shoes, and every scuff mark was prominently visible in the photos. In the past, I used to spend substantial amounts of time removing the most prominent scratches from the floor in Photoshop, but after reviewing many photos, I now think that the beaten-up floor adds authenticity to the shots. It conveys that the photos were taken not in an artificial environment of the photo studio, but in the actual dance school, where children spend a lot of time practicing their art.

Combining window light with strobes for portraits

AA5Q0944_07-08-2014.jpg

A large window at midday is a great light source for portraits. During a staged wedding photo shoot at the Empress hotel last  summer, I had a chance to combine window light with studio strobes. The colour matching between the natural and artificial light sources is not an issue, since “standard” studio light is daylight-balanced.

When the model is extremely close to the window, as in the photo above, the backlight provided by it is very intense, and it is easy to blend it with the strobe light. I shot this portrait at f/4.0 and 1/200 sec (ISO 200), which gave correct exposure for the window light. A single strobe fitted with a large softbox provided the light from the opposite direction. The resulting lighting arrangement is, essentially, equivalent to “cross-lighting”, when the model is located between two light sources of equal strength that are aimed at each other. The light distribution on the model is then controlled by her position relative to the imaginary line connecting the two light sources (if the model is located behind the lights, she is largely lit from the from the front; if she is mostly in front of the lights – she is backlit).

The difference between cross-lighting and the window-softbox arrangement is that in the latter case the light sources are, effectively, very large. This results in contrasty light (deep shadows, bright highlights) that, at the same time, has soft transitions between light and dark areas.

In contrast, the image below is shot with window light only. No additional strobes or reflectors were used to fill in the shadows. The dynamic range of this scene is quite high, but even when exposing for the highlights (so that they would not end up over-exposed), my Canon EOS-1D X fitted with a 85mm f1.2L II USM lens was able to capture some details in the shadows.

These two relatively easy lighting setups give completely different feels to portraits. Personally, I like the subtleness of natural light, and not having a strobe makes the shooting process more flexible and intuitive. However, without a flash to balance the window light, the range of poses that can be explored is fairly limited. Basically, the model has to be facing the window, or at least be partially turned towards it. With a flash, variety of poses is possible, including portraits with the window as a background.

AA5Q1298_07-08-2014-Edit.jpg

Shooting portraits by the bonfire

AA5Q3263_10-31-2014.jpg

It is Halloween time, and tonight we visited the huge Oak Bay bonfire organized by the local firefighters. Photographing people by the fire is challenging, and the camera settings depend on whether the light source, i.e. the bonfire, is in the frame or not.

If the fire is not in the picture, but simply shines the light on the subject, such as in the photo above, the basic concepts of shooting in low light apply. One needs a fast lens (one with a low minimum f-number) and a camera with good low-light performance. My wife used a Canon EOS-1D X with a 35mm f/1.4L USM lens.  I usually just let the camera expose correctly for the subject and not worry about the background, which will come out either over-exposed (if it is still twilight) or under-exposed, if it is already dark. In either case, it can be ignored if it does not contain anything of interest.

On the other hand, if the fire is in the background, in other words, if shooting against the light, the dynamic range of the scene (the difference between the lightest and the darkest parts) is too great for any modern camera to handle. There is no choice but to add artificial light to the subject. An on-camera flash is far from ideal light source, but it is often the only choice in a given situation. This is what my wife used to take the image below. In manual mode, if the aperture and the ISO are fixed, the shutter speed can be used to control the exposure. When checking the exposure, it is important to look at the histogram, since images on the camera LCD screen appear much brighter than they really are.

AA5Q3289_10-31-2014.jpg

Another challenge of shooting with a flash, with fire in the background, is that the colour temperature of the two light sources is very different. The flash is daylight-balanced, while the colour of the fire is very warm (red-orange). One way to balance the image is to correct the colour of the subject in post-processing. In Lightroom, this can be done using a local adjustment brush, which is what I did for this image. In Photoshop, this can be done using adjustment layers applied to a part of the photo.

An alternative to correcting colours in post-processing is to use gels on the flash. A gel is, basically, a piece of a coloured plastic, which is attached to the flash by a rubber band.

Personally, I prefer leaving the colour correction until I can see the photo on a computer and can experiment with various effects. After all, the warm colour of a bonfire creates a special atmosphere that is worth preserving in the final image.

AA5Q3134_10-31-2014.jpg

At the restaurant: dealing with low-light conditions

AA5Q6094_09-20-2014.jpg


Restaurant is a common setting for a group portrait, because dining out often commemorates a special occasion, as in the photo above – last Saturday we went out to celebrate my wife’s birthday. Using flash is not a good idea for several obvious and not-so-obvious reasons. In addition to disturbing other customers, a flash would completely change the character of the lighting, so capturing the ambiance would be out of the question.

Restaurants are typically dimly lit, so low light performance of the camera is very important. This characteristic cannot be narrowed down to one particular specification. It depends on the lens, the sensor and the firmware. Cell phone cameras cannot compete with DSLRs in this regard, so if you must use a cell phone, the first thing to adjust is your expectations.

If you choose to bring a DSLR, a fast lens (f2.8 or lower) is a must. Also, the lens-camera combination should ideally be relatively compact. In the Canon world, a Canon EF 35mm f/1.4L USM is an excellent lens for this situation. Sigma also makes a good quality 35mm f1.4 lens (Sigma 340101 35mm F1.4 DG HSM), which is quite a bit less expensive. (By the way, these are just recommendations based on my experience, and although the links are affiliated by Amazon, they are not sponsored in any other way). In fact, compactness would be a very good reason to choose a cell phone over a pro camera – after all, it is a dinner first and a photo opportunity second. Having said this, I shot this photo with a Canon EOS-1D X, which is anything but compact. My family is probably getting used to me lugging a huge camera. I’d like to think that the photos are worth it. (Still, I am waiting impatiently for my new iPhone 6 plus, with its image-stabilized camera…)

Here is a roundup of the best cameras for low-light conditions compiled by Adorama (as of Summer 2014). A colleague has recently used their top choice, the Sony Alpha a7S, to photograph a fluorescent helium jet seeded with acetone in near darkness in our lab at UVic. But that hardly qualifies as a common photography situation, so it’s a subject for another story.

As a more general resource for handling low-light situations, check out this book: Chasing the Light: Improving Your Photography with Available Light.