First Impressions: Sigma EM-140 DG Macro Ring Flash

Santa was generous this year, and brought me this welcome addition to my macro outfit.


Technically this is not a “ring flash” as it does not have a continuous flash tube running around its periphery, but rather two smaller tubes either side. But when both tubes fire, it essentially behaves like one. The two separate tubes allow modeling which gives a more three-dimensional result.

As third-party flashes go, the build quality is first-rate with a fit and finish comparable to a Nikon speedlight. It comes with a high-quality nylon storage case, with plenty of room for additional goodies such as adapter rings. The included 55 and 58mm adapter rings seem to be odd choices, but you can purchase additional rings or use step-up rings. I had to order a 67mm ring for my AF-S DX 16-85mm and AF-S 70-300mm Nikkor Zooms.

This is an  iTTL, DTTL or manual flash. There’s no built-in sensor, and thus no Auto Aperture mode, so, it’s uses may seem limited on non-TTL cameras. But that’s OK, because the manual mode is where this flash shines. You have the ability to dial in individual power settings for each of the left or right tubes, from full power to 1/64 or off completely. And you can easily rotate the flash head on its adapter ring to adjust the angle of the light source. On a body other than a Nikon, this is a purely manual flash, suited mainly to macro. On a Nikon film or Digital camera, the flash can be used in TTL mode for purposes other than macro work.

In TTL mode, hand-held macrophotography becomes lots of fun. There’s a built-in lamp for focusing on subjects in dark lighting conditions. Unfortunately, this happens manually, and it isn’t very bright. But in near-darkness, I was able to use it to compose and autofocus with a fast lens. By fast lens I mean a 50mm (75mm equivalent) f/1.4 normal lens with a 20mm extension tube. This was my initial test setup.

Once the exposure was dialed in with exposure compensation, the results were quite consistent, and the focus dead on. Of course the range of distance is about an inch, making auto exposure nearly academic. But it does allow you to change apertures at will to dial in your depth of field. And it will definitely increase your comfort level when used with film. I can’t begin to tell you what a pain it would be to calculate the guide number.

Turning off one of the flash tubes did indeed give a more three dimensional effect. I rotated the head so that the light appeared to come from the upper left, and it was quite convincing. Manual mode however offers more options, as the power can be controlled as well. I can easily see rotating the head 90° and doing clam-shell lighting in miniature.

With the extension tube off, and the AF-S DX Nikkor 35mm mounted, it becomes more of a standard flash with an interesting aesthetic. I can easily see exploring portraiture with this, even though it’s not a true ring light. The nice thing is, the whole assembly is quite compact and well-balanced.

The display and controls are easy to use. The display is not nearly as comprehensive as say, the Nikon SB-900, which provides a continuously updated distance scale; but it does the job.

I couldn’t resist trying this on my Nikon Coolpix P5100, despite the fact that it’s not among the list of compatible cameras in the manual. Sure enough, it seems to be very overpowered, but it might work with a neutral density filter. This might be worth pursuing, since bridge cameras can have enormous depth of field when used for macrophotography. But this is an experiment for another day.