Photographing Australian Plants

DIY Macro Flash Setup

Murray Fagg's quick and cheap flash technique for plant photos with a macro lens

Nikon D70 camera with side-grip The camera is fitted with a Nikon macro lens. Here the camera's inbuilt flash is not raised.
A simple diffuser Made from the transparent lid of a frozen cheese-cake container. The lid has been cut with scissors to the shape of the camera lens at the bottom. A piece of translucent tracing-film (from an art supplier) has been cut to the same shape and stuck on with small strips of sticky-tape. This can be replaced from time to time. Two clips have been glued to the transparent lid to attach it to the very front of the camera's macro lens. The clips were cut from cheap conference name-tags.
Attaching the diffuser The way the diffuser is attached to the front of the lens is going to be different for different cameras and lenses. Some people might find it easier to attach the diffuser to a standard filter-holder which already has a screw or clip fitting for their model of camera lens.
Camera with diffuser attached, inbuilt flash raised Here the diffuser is clipped on to the front of the macro lens. The important thing is that the diffuser moves when the lens is extended. When the camera's inbuilt flash fires, the light hits the diffuser which then becomes a much broader and diffuse source of light to illuminate the subject of the photo. The diffuser cuts down the power of the flash which would otherwise wash out the photos, even at very small apertures like f 22 or f 32
The role of the diffuser The tracing film cuts down the intensity of the flash. The diffuser now becomes a broad light source reducing harsh shadows. The diffuser also eliminates the shadow of the front of the lens which can ruin very close-up images if only the camera's inbuilt flash is used. Unlike a ring-flash which flattens images by almost emiminating shadows, the diffuser does not illuminate from below the lens, providing some modeling - the shape of a flower is clearer if some shadow is present.

Exposure

Some digital SLR cameras can be set to 'auto' and correctly set the exposure using this diffuser.
For the Nikon D7000 'auto' works quite well, setting the shutter-speed at 1/60 second and the aperture in the vicinity of f 25 for flower close-ups in dim light.

However I prefer to take photos using the diffuser with the camera set on 'manual', with the shutter-speed set at 1/250, and decide the aperture myself.

Deciding the correct aperture is helped by looking at the exposure histogram after the photo is taken, take another photo if necessary.

See the web-page on 'depth-of-field' where 'aperture' is explained.

Pros and cons of such a diffuser

Its very light to carry, not like a bulky ring-flash.

No extra batteries to charge or buy, as with most ring-flash units, if the camera is charged and operational, the inbuilt flash will work.

It works best on cameras where the pop-up inbuilt flash is directly above the lens, rather than to the side as on many non-TTL cameras.

It works best when photos are taken in landscape mode rather than vertical.
If the camera is held vertically, the light will always appear to have come from the side, giving a much less natural lighting effect.

It allows very small apertures to be be used, increasing the depth-of-field.

Photos usually have a dark background, which some people don't like.
The background tends to be less 'black' than when a ring-flash is used, some stray light from the flash usually reaches the surroundings.