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Getting close with SIGMA - part 5 of 1 2 3 4 5

by Mike McNamee Published

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Colour test EM-140. The charts shown were shot using the Nikon D200 set to Flash White Balance and using iTTL exposure, set to deliver one stop of addional exposure. The aperture was 5.6, the working distance 2.3m and the ISO 100. The colour accuracy of the shot was impressive, spectacularly so after the final tweak in Adobe RAW, which left a residual error in the skin tone of just 1.9 ÄE Lab. Such good data will be of interest to those wishing to use the set-up for intra-oral medical work.

Why use Macro Flash?

Macro flash is not the best option in all circumstances. For medical intra-oral work it is essential. Engineers, recording in tight conditions will also find it indispensable (eg inside pipes). One of the problems using this kit for natural history work is that the lighting is a little flat, especially at greater working distances. The trick is to balance the effect of good working distance from the insect and the flatness of the lighting.

In the studio we found that the lighting from the EM-140 was a little harsh for jewellery and, given that such objects do not move, there is little to be gained over a slow shutter speed and the DeVille dome which produced a much more pleasing light.


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A shot made on the Nikon D200 using the EF500DG in TTL mode. Shot in RAW then a 0.2 stop exposure adjustment and a 3-RGB point colour adjustment for a really accurate result.

Colour Performance

Ever protective of the highest standards we used the latest version of Adobe RAW and calibrated the flash output and camera using ACR-Calibrator. This produced quite a good result although the rendering of the textured paper surround of the Macbeth Chart was a little too light.

Field Trials

We took about 100 frames in "the wild" using the 150mm Sigma Macro and the 140 Macro flash. The results were a little mixed due to ineptitude on our part; we pushed the shutter drag too far and ended up with slightly fuzzy shots! This was not a feature of the flash; at the magnifications we were working at, camera and/or subject movement are very critical and you still need a tripod with flash if you wish to drag the shutter to prevent the dreaded "black background". Ignoring the lack of sharpness, the double shadows created by the twin flash were distracting on things like flower stamens. Using different powers on each side, as with the wasp, did create some modelling and lit the inside of the nest hole entrance at the same time. Overall we obtained better field macro using the EF-500 DG Super and the Gary Fong diffuser.

Using the combination of the Nikon D200, the Sigma EF-500, the Sigma 150mm and the Gary Fong Lightsphere we spent a happy morning chasing Holly Blues around the garden. Having learned from our earlier experience we pushed the flash synch speed out to 1/200th to stabilise the ambient portion of the light. This worked reasonably well providing we held steady although chasing blues is always a high speed affair, certainly there is absolutely no chance of ever getting a tripod in place. The shot shown is part of a D200 file, shot at 1/200th f16 (100ISO) at around half life size. This computes to an effective aperture of f22, leaving the ambient light at around two stops less than the flash. The background has remained reasonably bright and the shadow cast by the sun has been retained, so the exposure conditions probably represent the best compromise in the circumstances.

The Final Verdict

The EM-140DG is really only reccomended for intra-oral medical work and the like, for field macro work we got on a lot better with the EF-500DG. The 150mm lens however is a real beauty, right up there with the standard we have come to expect from Sigma. Although the extra working distance comes with the need to take more care on camera shake it is certain to improve your hit rate on skittish species. This extra working distance also increases the number of options available to you in terms of lighting arrangments and diffusers.


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1st Published
last update 09/12/2022 14:54:40

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