Tuesday, April 2, 2013

The Essential Guide to Macro Photography Lighting Options

There comes a time in every photographer’s life when they toy with the world of macro photography. As with all photography, the desire to stay with Macro Photography is highly linked to their ability to "paint with light" in this world of miniature and very small and the success of their results.

Outdoor provides great lighting opportunities to get close to nature

This article does not describe the "how to" of macro photography, but rather focuses on different options to use artificial light to help create successful macro images. The definition of Macro Photography used here covers both macro images that have a 1:1 size ratio of object to sensor and very small objects, such as a coffee bean or small flower.
  • Something very close up
A ballpoint pen tip - lit from the left with a reflector on the right

Colored straws - lit from beneath

  • Something small, but not necessarily 1:1 ratio
The center of a flower - lit from above

Small food items - bounce flash off a white ceiling

On-Camera Flash

Typically the first hurdle that people face when exploring Macro Photography, especially with Point-and-Shoot cameras, is getting enough light on the object.  There are two main reasons for this:
  1. The apertures used for Macro Photography are generally upwards of f/16 to ensure a good depth of field.
  2. The way Point and Shoots work best with Macro Photography is by setting the camera to the widest angle of view, e.g. 24mm, 28mm, and then moving the camera up very close to the object, e.g. 2-3 cm.
Point and shoot cameras can create shadow nightmares when shooting so close

The problem with the above two points is that the first restricts the amount of light entering the lens, therefore forcing the user to use a tripod and ensure that the object is stationary.  The second point typically causes a shadow to fall of the image making it vary dark or even worse cause part of the image to be in shadow and the part in light causing a big contrast of light in the image.
  • To get enough light onto the coin with my Canon G12 I had to use f/2.8 at 1/20 of a second, making the coin partially in focus as well as half of the coin reflecting the image of the camera due to the close proximity of the camera to the coin

To overcome the problems of slow speed or shadows typically requires introducing a secondary light source to control the light that creates the image.  Initially the first go-to-source to solve this problem is on-camera flash.  Unfortunately this introduces a similar problem to the shadow problem mentioned in point 2 above.

  • To get the depth of focus I changed the setting to f/8 @ 1/60 and add flash.  The image below shows the strong shadows that are produced by the camera with the on camera flash at such short distances.

  • Using the DSLR with a dedicated Macro lens and an external flash unit still creates a show problem

To solve the problem of shadows the photographer has two choices, either move the object further away from the camera or move the light source off the camera, which is the main topic of this article.

Before we delve into off-camera lighting let's look at what can be done using both the internal camera flash and an external flash mounted on the camera to create better macro images.

The first option is to move the object further away from the camera, which allows the on-camera flash to light the whole area of the object.  The two downsides to this approach are (1) you will not be able to capture the same size of the object on your sensor compared to when it was closer and (2) using on-camera flash may light the whole image, but creates a flat boring image.

When lighting from straight on-camera for macro images you suffer the same problem with other types of photography that it doesn't allow you to capture texture in the object, which Macro Photography thrives on to create interesting images.
  • Moving the camera away from the coin allows me to get rid of the shadows, but produces a much smaller image that looks very flat.

If you're stuck with having to use on-camera flash there are one or two tricks you can use to capture a better image.

Diffusion material to spread light over the subject.

For cameras with an external flash adding a Stofen filter or other diffusion device will soften the light.  However using a Point-and-Shoot is much harder as the flash is attached to the body and has little flexibility to add a diffusion device to the unit itself, but all is not lost.  With a bit of ingenuity and fiddling it's possible to position diffusion material between the object and the flash to create a diffused soft light.

  • The result of fiddling around with the position of the diffusion material (in this case plain white paper) can give fairly good results.

Paper is placed in-between the flash and the object to diffuse the light

  • When trying to shoot close up, a trick is to move the object to the side of the camera where the flash is located.  This will help you get a more even light over the object.
The flash on the G12 is on the left side of the camera.  Moving the coin to the left evens out the light
You can always crop the image later to make it more even
  • The diffusion material was easier to place between the flash and the object on the DLSR

  • The diffusion material helps to diffuse the light, but create an unwanted dark reflection in the camera.  The angle of the light does however create some texture from the coin, but it is far from ideal but better than the picture with the shadow above.

Bouncing on-camera flash unit (e.g. 430 EX II)  off a reflector to the side/top.

The best external flash unit for this is one that fits on top of your camera and has a head that swivels up to 90º either way.  This allows you to angle the direction of the light and bounce it at some kind of reflector device to create both a larger light and something close to off-camera lighting. Just be aware that the colour the device you use to bounce the light off will affect the colour that is reflected onto the object.
  • The setup in the first image below shows the on camera flash pointing down to the table and the reflector board behind it.  The second image show the flash head turned nearly 90º to face the reflector board.

  • With the bounced light I get nice texture in the coin without the dark reflection of the camera in the coin.  This is a fairly nice result from on camera flash and can be achieved with any camera that can attach an external flash unit.

Off-camera flash

As discussed above, you have limited options when trying to light a macro image with on-camera flash, when you move the lights off-camera you have exactly the opposite problem - too many options.  All the benefits of taking the flash off camera in other forms of photography apply to Macro photography, including creating shape & form, bringing out texture, create dynamic images, etc.  Lighting for macro images is much more tricky and much less forgiving than in other forms of photography.  The three basic differences that make off-camera lighting trickier and less forgiving are the affect of:

Light size is affected because of the difference in the ratio between the light source, i.e. flash, and the object that you are photographing.  In, say, portrait photography the size of the flash head to a person's head is very different than when photographing a fly or coin. Where the size of the flash head is relatively small compared of a person's head, it is positively huge compared to a small coin, giving you the ability to get "large" light straight out of the flash unit.

Light strength is a direct relationship between the distance from the object and the flash unit.  When using a flash unit off camera and trying to get close to the object the strength of the light makes it look like a spotlight lighting up the Empire State building and blows out the image.  

Even when powering down the light to it's lowest strength or 1/64th or 1/128th, it can still be overwhelming.

1/64th power

1/128th power

Light direction is trickier in Macro Photography because the movements you make when changing the light are exaggerated compared to other forms of off-camera flash photography.  Small movements can make big differences how the light falls on the image and it can become fairly frustrating sometimes when trying to get "THE" angle.

Three ways to get off-camera flash

As with other forms of off-camera flash photography there are three main ways to take flash light off of the camera.
  • Flash cords are the cheapest and easiest option if you want to keep your budget low and want to stick with one flash.  The cord plugs into your hot shoe and onto you flash and gives you all the same control over the flash as if it were on-camera. There are two types on cords
  • Spiral cords are very common, but have problems with Macro Photography due to the bulkiness of the cord and the fact that has you maneuver the flash around the cord acts like a spring and pulls the camera out of position - which is not a good thing at all in Macro Photography where small movements in the camera make a big difference.

  • Straight cords are easier to use than the spiral cords as they don't move the camera.
[image care of http://flashzebra.com]

  • Radio and optical triggers can be used to trigger off-camera flash.  These both have reliability issues when working in very close proximity to the camera.  The radio slaves are the most reliable but can act strange when the transmitter and receivers are placed very close to each other.  Optical triggers are very cheap, but need to be able to see the flash of light from the on-camera flash.  This is a bigger issue for Point-and-Shoot cameras where the flash is typically on one side of the camera that for DSLRs where the light is on top.
Pocket Wizard Radio Triggers

Optical Trigger

  • Using two flash units in master / slave sync mode also works to get you light off-camera.  There are limitations here also for close proximity Macro Photography due to the line of sight that that the units need to have and the angles which the line of site works.  Reading you user manual will help you know the limitations for your flash unit.
Master Mode on a Canon Flash
Slave Mode on a Canon Flash

Hand Held vs. Light Stand

When lighting a macro image with off-camera light, circumstances will often dictate whether you hold the unit in your hand or use a device to hold your flash unit, like a light stand.  When out and about photographing flowers or other small objects you may decide that carrying a light stand as well as a tripod is too much.  In this case having your camera secured on a tripod frees one of your hands to hold the flash unit when taking the image. At home however where you don't have to carry all that extra gear on your back, you have the ability to use a light stand to hold the flash unit when taking the photograph.
  • Hand holding a flash connected by a flash cord

  • Hand holding a flash connected by a triggers

  • A flash on a light stand connected by a flash cord

What I personally find useful when using a light stand is to hand hold the light and take a few images from different angles, then review which angle you prefer.  Once you have decided where you want to place your light you can then secure it to the light stand and fine-tune the image with smaller more controlled movements of the light.

When moving lights, it's important to keep in mind that the small distances between the light and object means that small adjustments can make big differences in lighting.  Remember the inverse square law says that moving the point of light source twice the distance from the object means that the object will receive a quarter of the light.  This means that if you are lighting from 2-3 inches from the object then moving the light 1-2 inches means adjusting the power of the light or aperture on the camera accordingly.

Manual vs. ETTL Control

When lighting macro images, I typically recommend using manual lighting due to the small distances from the light to object.  Manual control provides a consistency of light at such close range. ETTL problems are exacerbated when using a Point-and-Shoot to do macro, but can also be an issue when shooting with a macro lens on a DSLR.

Dedicated Macro Flash Units

Dedicated macro flash units are very useful if you decide to invest into macro photography.  A dedicated macro flash is typically an off-camera flash where the lighting heads are connected to the camera via a cord.

Typically the lights are fitted to the end of the lens so that the light covers the whole image.

I use Canon products for my photography and purchased the Canon MR-14EX TTL Macro Ring Lite Flash Pictured here, due to its price being half of their other macro flash product, the MT-24EX.  This flash unit has two flash heads opposite each other that can be rotated on the lens 360º.

This unit does a good job for basic macro lighting but the position of the lights is fixed, therefore limiting your ability to be creative with lighting.

A few useful functions are:
  • The ability to switch off either of the flash heads
  • Select a ratio for lighting strength between each of the flash heads
8:1 Ratio Left
1:8 Ratio Right

  • It has two small lights on the ring that you can switch on to help you focus
  • The unit can act as a Master unit to trigger Slave off-camera units
  • You can take the flash head off the lens and handhold it, but the spiral cord limits its length.

For the more budget minded photographers, you can find many DIY solutions on the Internet that address the problem of getting a flash "off-camera".  A good place to start is to go a search on Google Images for "Macro Flash", and you will amazed at the creativity of some of the solutions.

Light modifiers

There are a number of light modifiers that are useful when lighting macro photographs. Unlike other forms of photography the size of the modifiers don't have to be large (or expensive!)

Neutral Density (ND) Gels

  • The first light modifier is not technically a modifier, but rather a light reducer. Flash gels are pieces of plastic gel that fit onto the flash head and are normally used to modify the color of the light. Neutral Density (ND) gels do not alter the color of the light, they just reduce the amount of light that hits the object.
  • When using flash units off-camera for Macro Photography they often emit too much light due to being so close to the object, even when you reduce the light output to the lowest setting.  Adding an ND gel to the flash head helps to reduce the light hitting the object even further.
  • ND gels usually come in sets that reduce the light by 1, 2 or 3 stops.  In extreme cases you can double or triple up the flash gels to further reduce the light emitted.

Stofen Light Diffuser

  • Stofen diffusers or similar types of diffusers are great for reducing light (similar to using ND gels) as it will reduce the light hitting the object by 2 to 2.5 stops.  The main benefit of the Stofen is to create a softer diffused light by spreading the light and allowing it to be bounced of reflectors or other reflective surfaces.

The Stofen diffuser fits over the head of the flash

Light box

  • Small light boxes are perfect for creating beautiful soft wrap around lighting.  Your off-camera lights are placed outside the light box and the object you are shooting is put inside.  The white translucent material creates a large diffused area of light and the box allows you to place lights on the left and right side as well as top and back, giving you a host of lighting options.  There are many different models on the market and a Google search for "DIY light box" will give you a host of cheaper options.
The flash on the camera is the master flash and the other two are set to slaves
Lightboxes give a nice soft overall light

Soft box

  • Small soft boxes, like the Lumiquest Softbox II, are great for creating "big" soft diffused light for macro images.  These also reduce the amount of light that falls on the objects and are very versatile for lighting at any angle.
Positioning the soft box takes time to get the right light

Soft boxes give a nice light, but can still cause specular highlight issues on shiny subjects

One light off-camera flash - Image of a Canadian $20 bill

  • One light low across the $20 bill gives fairly good texture

  • Close up reveals the texture of the imprint and paper

  • Dedicated Macro flash gives a flat lighting, but nice reflection from the gold strip

  • The close up reveals little of the texture in the paper or the imprint

  • Softbox with a reflector gives a flat lighting with a little hint of the imprint

  • The close up reveals little of the texture in the paper or the imprint

Two lights off-camera flash - Image of a Canadian $20 bill

  • Softbox light left and Stofen diffuser right opposite each other

  • Close up reveals a flat image as the light from each flash unit has cancelled each other out.

  • Bare light left and right opposite each other

  • Close up reveals a fairly flat image (but less flat than the two diffused lights above) as the light from each flash unit has cancelled each other out.

  • Bare light left and top

  • Close up reveals a lot of texture in the paper as well as the imprints in the paper

Ultimately the best light source is the one that helps you to create the image you're looking for.  Using natural light is great, but when mother nature decides not to co-operate, your destiny is squarely in your hands.  To increase your chances of being successful, practice with what you have to understand the limitations of your camera's macro capabilities and how best to work your lights, both on and off camera, to overcome those limitations, so when the time comes nailing the image will become second nature.

Please feel free to leave comments or questions below or you can email them to me.