Pixiq

Over the decades that I have used and built flash systems for close-up work, my goal has not changed: to create a set-up that is portable, reliable, consistent, robust and works on as near a 'point-and-shoot' basis as possible. I want to concentrate on the subject not the gear.

What follows is the first of three posts dedicated to that approach with a look at various practical options and problems with lighting close-ups in the field.

So, do we really need flash sources for close up?

Some folks cite black backgrounds (unintentional) and harsh shadows as the inevitable horrors of flash, but this need never be the case with a little care and mastery of technique.

There is a perennial problem in macro work — moving closer with a macro lens (and magnifying the image on a sensor) you get shallower depth of field. So, to increase depth of field, you use smaller apertures, but closing down the lens diaphragm cuts down light ... so you use slower shutter speeds (OR increase the ISO rating — great if you use FX). But now the slightest movement of camera or subject causes blurring. With flash, the burst of light is a movement-stopping millisecond or much less on fractional power.

What are the options?

a. No Flash — Increasingly possible in many situations for those who have FX cameras like the Nikon F3S with its superb low light responses. It can be set to ISO 800 and much more with no apparent image deterioration so you can shoot close-up with daylight, small aperture and a shutter speed of 1/250^th sec or faster that freezes movement.

b. Flash on Camera

An integral flash can produce excellent results as long as you use a longer focal length macro or zoom lens. These flashes are never positioned quite high enough, and the front of a lens can cast shadows with shorter macros and close-focusing wide-angles.

I often use a Nikon SB 900 on top of the camera (my version of traveling light) with diffuser fitted — it gives a pleasing light which I then often mix with background light. To do this the camera is set in ‘manual’ mode with background exposure set to about 1 or more stops below the ‘correct value’ shown on the linear scale in the viewfinder. The DTTL flash system takes care of subject exposure.

 c. Off-camera flash — including macro flash systems

Positioning a flash gun off-camera via extension cord (or radio control) gives better ‘relief’ where off-axis illumination creates tiny shadows on the surface of a subject enhancing texture and aiding that all-important impression of sharpness.

You can use one or more guns for versatility — in general, one gun is used as the main light, the other as the ‘fill’ to lighten the shadows. Another flash can be positioned away from the camera to iluminate the background, but I usually use available light for this because I like the balance between flash and ambient light. 

With two flashes you can adjust their position (or control the flash power ratio) to give a lighting ration of about 1:4 eg to get ¼ power (2 stops lower) double the distance of flash from subject compared to the main gun … assuming they are identical guns (the inverse square law).

You can get away with a single hand-held flash holding the gun against the camera with the left hand (vice versa if you are left-handed) and the other presses the shutter/focuses. If shadows are a bit harsher than you want, then use a reflector on the other side to throw light on to that side … or a diffuser on the flash.

So, are Macroflash systems the answer for you? See parts II and III for an assessment.

A couple of extra techniques can be used to provide variety

Backlighting: A single gun behind and to the side of a subject creates a rim light that accentuates hairs on flower stems or on insects — it is a little bit of magic that can raise your pictures to a different level. With radio-controlled systems it is easy, and a manual gun with a photoelectric trigger works too since the lighting is not critical — just avoid placing it too close and anywhere in line with the lens axis.

Darkfield: This is a dramatic form of lighting borrowed from microscopy — in effect backlighting against a black background. A disk of black card/flock paper forms the background, and light comes in from behind and to the side.

What extra do I need working ultra close ?

Nothing: a single, small, handheld gun operated from the camera TTL system (or manually) is all you need for larger than life-size, those ‘true macro’ shots. At close quarters a small flash acts like a ‘broad source’ (like a flash with diffuser or umbrella) and creates a pool of light on the subject; a white card placed on the opposite side reflects to fill shadows (if any). If you use TTL systems the time to control the pulse is very short (nanoseconds and less), so cable length matters and affects the response time so you might have to experiment with the compensation buttons to get correct exposure.

How can I avoid unwanted dark backgrounds?

Make sure that some background leaves, stones, ground, etc., are close enough to get illuminated alongside the subject (even a stop or so less). Best of all, as already mentioned, mix flash and ambient light by using ‘slow synch’ or setting the camera on manual, adjust the camera shutter speed and ISO to capture the background (about a stop lower than the flash). This is the method I prefer where a touch of flash adds ‘bite’ to colors. Watch out for ghosting (see part 2) — wait for lulls in the breeze ...

Remember black backgrounds come and go as a fashion … so never get rid of old images.

Check out part 2 here and Part 3 for the complete picture