- When using AF – note that the selected AF point won’t always align with the section of the subject required for sharp focus or might be too big giving accurate focus on for instance the eyes of a fly, therefor MF can be used to fine-tune the focus. Some lenses allow full MF override when in AF mode.
- Focus and recompose is not a technique to be considered due to the short working distance and resultant narrow DoF – the parallax error can result in soft images.
Macro Photography tips and tricks
Sigdmin
Macro photography is seen as 1:1 (life size) or bigger. Some would include 0.5:1 (half-life size) also as macro, but it is generally not accepted as such. Anything less than 1:1 must be viewed as close-up photography. No zoom lens I know of will provide true macro magnification used on its own irrespective of what is printed on the lens barrel.
The difference between true macro and close-up photography is demonstrated by the dragonfly images, close-up on the complete insect, then full macro on the head only. He was just finishing off a small white moth at the time.
Refer to dragonfly images – Both images taken with Canon EOS 1D MkIV and 180mm Macro lens with 25mm extension tube, 1/250, f14, ISO 200
Macro or close-up can easily be done in your garden, or indoors in your house. Both macro and close-up photography require a very high degree of sharpness and crispness, extreme Depth of Field (DoF) control and very good color rendition.
There-in lays the biggest challenge of proper macro photography – the extremely narrow DoF resulting from the short working distances when focus is set to nearest limit, makes accurate focus and proper DoF selection crucial to obtaining the desired end result. Using a 180mm lens on a 1.3x crop sensor (my Canon EOS 1D MkIV), at a minimum focus distance of 47cm, and an aperture of f3.5, results in a DoF of only 0.5 mm, and at f16 it is still only 2 mm!! An added advantage is the crop sensor effect, it allows for the changes in the perceived focal length of your lens. If you are not using a true macro lens, and going for close-ups with you regular zoom or prime lens, then the issue will not be as severe since your minimum focus distance will usually be around 45cm. Check the specs of your lens, and test it before you attempt serious small insect stuff.
For some extra magnification I sometimes use a 25mm extension tube on my 180mm macro lens. It does allow me to use a shorter minimum focus distance, and with the standard longer stand-off distance from the clean 180mm Macro lens it is easier to handle, not scare insects away. Remember with shorter focal length lenses, such as the Sigma 105mm macro, your minimum distance is 31 cm, and with an extension tube it could less than half of that. Makes it easier to scare away those skittish insects. Gets worse if your macro lens is of the 50 or 60mm versions.
To calculate the added magnification when adding an extension tube, use the formula : Tube length, divided by focal length = added magnification eg, 12mm tube / 50mm lens = 0.24x added. If a 180mm Macro lens at 1:1 is used, 12 / 180 = 0.067 thus 1:1.067 Therefor ET’s are more effective when using shorter focal length lenses.
With the short lecture out of the way, here are some tips and tricks I’ve learned over the years.
Let me start off by saying that I do all my macro work hand held and “in the field”, ie no light tents, or freezing insects and then placing or posing them, or horrors of horrors; gluing them to a twig for tight macro head and eye pics. Please be ethical in your macro work and never harm or seriously disturb their habitat like destroying spider webs and so on.
My personal preference, used most of the time as basic start setting, is Manual mode, shutter speed (ss) of 1/250, aperture f16, with slight changes according to need and use of flash.
On the subject of flash, use what you have, or get specialist macro flashes such as a ring flash or twin-head flash. I use my standard EX 430 MkII flash gun mounted on a self-made bracket which allows the flash to lie just above the lens barrel, at a slight kink and with a diffuser fitted to the flash head. Nice soft directional lighting and I can change the angle or rotate the bracket as I like. Just make sure you can get enough light onto your subject, and that the flash is not screened by the lens hood or lens barrel. Will cast an ugly shadow over your subject.
Nothing stops you from using any camera mode setting though, pick one you feel works best. Camera mode (Tv, Av, M) will be dictated by the conditions and type of subject material.
If you don’t use M mode, then I suggest aperture priority mode if DoF control is required (usually) and in low light conditions where stable support is available which will prevent camera shake at slower ss. If you have a macro lens with stabilization it will be handy
Use shutter priority where subject movement needs to be frozen or adding for e.g. induced wing blurring effect on flying insects. Flash helps to freeze movement but not all of it.
Manual mode can be used where conditions require the use of external light sources, such as flash. Set manual mode to achieve desired ss effect, and aperture to accommodate DoF requirements. Correct exposure will then eb applied by your external light source. An E-TTL setting on your flash gun usually works well enough.
Metering – select partial for accurate metering from a certain area of the subject, but evaluative / matrix / 3D metering can also be used. I have found that spot metering can be too specific leading to exposure errors.
Either AF or MF can be used, I use manual focus for about 80% of my macros – consider subject type, basic shape, static or moving, support system in use etc.