Macro Lighting – a detailed review. PHD

I love wandering with camera plus flash at the ready, relaxed and ready to discern and capture images at close quarters. What follows is dedicated to that approach and there are various practical options open to work in the field. In your ‘home studio’ you can also think about incandescent desk lamps (care – they heat the subject), Fibre optics (useful for high magnification work – particularly for focusing before using flash as the main exposure. And now there are LED’s which give bright light without heating: I’ll cover all these in later posts

Flash on Camera

An integral flash can produce surprisingly good results (well it surprised me!) as long as you have a longer focal length macro or zoom lens since these flashes are never positioned quite high enough and so the front of a lens can cast shadows if you are too close to a subject.

If I am travelling light (hah, hah..) I will use a Nikon SB 900 on top of the camera with diffuser fitted – it gives a very pleasing light which I then often mix with background light. This camera is set on manual with background exposure set to about 1 or more stops below the ‘correct value’ shown on the linear scale in the viewfinder. Most of my fungi shots are like this and ‘specular’ reflection from the surface reasonable controlled (see below)

The diffused light from a powerful gun will illuminate subject and background without creating ugly shadows

Off-Camera flash

You can use one or more guns to produce various effects. In general one gun is used as the main light and the other as the ‘fill’ to lighten the shadows (not always needed if the first one is well-diffused). And then a light on the background…I usually use available light for the background getting a balance between flash and ambient light. 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 employ a second gun set to lower power or, with a manual gun held further back.

Position and relief: a small flash used off camera close to a subject has great potential. First you need to light off axis because this creates tiny shadows on the surface of a subject that enhance texture and help create that all important impression of sharpness.

In practice you can adjust position (or control via flash power ratio) to give a lighting ration of about 1:4 . 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)

Ghosting: when balancing daylight and flash you have to watch out for ghosting where the flash freezes the subject but the camera shutter remains open long enough to expose movement and create a ghost. Sometimes you will not see it until the image is in Lightroom or Photoshop. Remedies include making sure you use a fast enough shutter speed (1/200^th or less) making sure you press the shutter in a lull in the breeze. At high magnifications (dealt with in a later post) some cameras really do create blur thanks to shutter bounce – rear curtain synch helps.

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 raises the game and your pictures go to a different level. With radio controlled systems it is easy – a manual gun with a photoelectric trigger works too since the lighting is not critical…avoid placing it too close.

Darkfield: This is a lovely form of lighting borrowed from microscopy where a dark disk of card/flock paper forms the background to your subject and light comes in from behind and to the side – I’ll cover this when I deal with larger than life shots

Ultra close: Many of my ‘true macro’ shots are just taken with a single small, handheld gun operated from the camera system and held to create a pool of light on the subject and a white card placed on the opposite side 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.

Specular Reflections

Many insects, beetles in particular have hard surface coatings that reflect light an create ‘specular reflections’. It is essential to use a diffuser to minimise these or to rid yourself of them build a sort of portable lighting tent that is placed over a beetle on a forest floor and lit from outside. Your background is restricted though!

Too many legs

Using two flash guns of similar power with insects creates multiple shadows and beasts with more than six legs…it’s a question of angling the second flash and reducing the power of this fill-in

Ring Lights

Ring lights produce a flat lighting that works great for the interior of cavities dentists use them (no pun intended) for imaging the interior of the mouth. I have found that macroflash units such as the Nikon SB 28s and 29s and the Sigma macrolight look like ring flashes but allow different power ratios between the tubes: one side is the main light and the other the fill-in. At close range these work very well – with ring flashes I always used to use black tape to create windows of different sizes on either side.

Macroflash units

Over the years I have written a lot about using home-made brackets and bits and pieces to hold these guns…a DIY macroflash unit. I used to prefer these because I used more powerful guns than the small units included in macroflashes. This mattered when using Fujichrome Velvia 50 and Kodachrome 25. Nowadays my minimum is ISO 200 and often more so I can shoot in daylight at f/16 – f/22 and get light in the background at 1/250^th sec.

There are some very good commercial units by Novoflex and others (see the Speedgraphic catalogue)… or you can get a few bits of allow tube, commercial flash holders and off you go. I used a butchered version of the Kennet Macroflash (they made the original Benbo) for years and still do at home. Commercial units are expensive but very convenient and easy to use repeatedly if you are really dedicated to macrophotography.

One of the very best units I ever used was the original TTL macroflash from the Olympus OM system. I then used the Nikon SB 28s and then SB 29s with film. In fact, for me the arrival of TTL flash that read light reflected from a film surface was an incredible boost. Canon patented it but did not use it for a long time and it was the reason I bought into the Olympus system at that stage. It greatly increased the proportion of ‘hits’ over a calibrated system and guesswork.

In the early days of my macro work I tried to get automated flash by building a flashmeter and making a probe that I held against the eyepiece of a Canon F1 and the screen of a Bronica S2A…it was not exactly ‘miniature’ and fitted in a sandwich box: hey, it worked.

This was a stage when I was keen to build electronic devices and set about making hi-speed flash guns (with lethal voltages) and a twin-flash macroflash from a couple of eviscerated flashguns. Some years after using this I was told that I had been seen near Hatchet Pond in Sussex where I was trying to get shots of the tiny Bog Orchid (Hammarbya paludosa) up to my waist in a floating bog and flinching like a demented gnome every time the flash went off…acid bog waters conduct electricity well and the plugs from the flash had sunk…dedication to one’s art. These days I need the time for other things…including survival.

Sadly, the non-reflective properties of a sensor surface created huge problems and TTL guns for film would not work with a DSLR. However, that was not the obstacle it seemed, for with a little practice (always using the same aperture) you could calibrate a gun by looking at the LCD to give you the right exposure. When you have something that works you keep the gun in the same position relative to the lens front: move closer and the gun moves with you – both light from the gun and from the subject obey the inverse square law, so there is compensation and no need to change exposure). For bright subjects you close down a stop dark open up…Thus for a few years I used a D100 with the SB29s as a manual gun…

I also have a Sigma EM 140 DG macro flash TTL unit that works very well with an SD14 camera (and the previous SD10 ansd SD9 models) and is a well-built, reliable and practical alternative to the more expensive offerings from Nikon and Canon when used with a 105mm or 60mm macro lens.

For the past two years I have daily used the Nikon R1C1 – a catchy little monicker, that makes it seem like a down-market Star Wars Robot. It has been through well over 10,000 exposures so I thought it would not hurt to write a user’s appreciation of this outfit from someone who uses it seriously.

read it here

© Paul Harcourt Davies