One of the problems with macro photography is a need for ample light. Shooting in daylight is always a pleasure but not always practical depending on the weather and the subject being shot. With focusing distances somewhere around an inch or two between the front of a lens and the subject, on camera flash is not a very viable solution for an even, consistent effect. Even taking the flash off camera is not optimal without some willing assistants or a well laid out shooting area. Considering moving from subject to subject? Then a handheld flash solution looks even less enjoyable.
Enter the specialized macro flash. In this case, a MT-24EX by Canon (lent to me by the fine folks at BorrowLenses.com). While a ring flash can give a nice even light and works in certain macro situations, the macro flash (actually two strobes with one triggering unit) takes this a step further by allowing for different angles of light as well as adjusted ratios between the two. This particular strobe also can control a third strobe to add in another light dimension.
The MT-24EX attaches to the hotshoe of SLRs just like any flash and then uses an adapter ring sized to the particular lens to be fitted (52mm and 58mm are the current choices). The ring screws onto a lens as any filter will and then the flash mount clips onto the ring with an easy to use quick-release system. Each of the strobes has its own holder on the flash mount to make break down into a nice, small package easy.
The unit has a few useful features. First, the unit can switch between manual and TTL metering control and I found the results with TTL very satisfying (although not always perfect). The unit's rear controls are the same as most other Canon strobes except for the + and – controls, as well as the < and > arrows. I much rather prefer the wheel and select controls of strobes such as the 580EXII. Not only will the MT-24EX allow for adjusting the ratio of the strobe units, it can also wirelessly control a third strobe when that strobes is set to slave (or multiple strobes set to the same channel). You will see this in action at the end of the post.
Setup and adjustment of the strobe is fairly easy. The main unit attaches to the camera hotshoe and then the main ring clips onto the adapter, having been previously screwed onto a macro lens. Then the strobes have an easy slide-in clip on the ring. The position of each strobe can be adjusted in two manners: 1) a press of the button shown at right allows the strobe to circle around the lens, covering a range of about 130 degrees and 2) the strobes will pivot in and out, on a marked scale (also shown at right) for objects near and far. The darker hash mark indicates straight forward.
To show the main advantages of this strobe unit, I will present a number of photos with the strobes at various configurations, pivots and ratios. I have mirrored the image of the flash unit so that the configuration matches the photos.
These first four shots play with the pivot of the units. The first shot is with the strobes angled directly at the pencils, about two inches (6cm) in front of the lens. Then the strobes are pointed straight forward, outward and all the way inward. (click on pencil images for a 2000 pixel wide version) All shots were taken with a Canon 7D, Canon EF 100mm Macro L lens at ISO 100, f/22 and 1/250. The pencils were kept the same distance from the lens in all the images and were approximately 1.5 feet (50cm) in front of a slightly off white wall with very little ambient light.
Next, I played around with adjusting the ratio of the strobes. This first shot below is at 2:1 (left:right) then 4:1 and finally 8:1, the maximum ratio to be achieved with the flash controls.
Now it is time to move the strobe units around the ring to demonstrate the different lighting effects to be achieved. Again, the image of the camera is flipped to match the light configuration of the pencil image. The largest impact these changes have is on the placement and intensity of the shadows on close-up objects.
This last set of images includes the use of a third strobe, a Canon 580EXII, set to slave mode and controlled from the MT-24EX. Each shot is captioned with noted changes. The first shot is the control with a 1:8 ratio and configuration as shown.
Lastly, the unit also has a pair of modeling lights which help illuminate subjects both for focusing and to estimate how light and shadows will fall within the scene.
With a the amount of variables available on the Canon MT-24EX flash unit, macro photography becomes far more interesting. The amount of control, both with the individual strobe units (each strobe can be turned off altogether to allow only one strobe to fire), the ratio, the angle and the inclusion of a third flash for additional lighting, makes this kit a worthwhile addition for anyone wishing to become serious about macro work in hard lighting situations. The kit retails for around $800US. Sto-Fen also makes flash diffusers for this particular kit. Thanks again to BorrowLenses.com for the lend. The technical specifications can be found at Canon's website.