One of my photography related Christmas gifts this year was a JJC LED ring light from a UK Highland Photography via Amazon. As can be seen from the photograph, the LED ring component attaches from the front of the camera lens using one of six possible adapters (thread sizes 49mm/52mm/55mm/58mm/62mm/67mm). Power is either from 4x AA batteries in a pack which attaches to the camera base via a standard tripod screw thread, or from a 240v mains A/C adapter. The build quality on the unit is very good and there’s not much weight to it (aside from the AA batteries). The photo below shows the ring light attached to the battery pack, in turn attached to my Nikon D90 via the tripod bolt
First of all, it is not really right to compare this LED ring light with much more expensive ring flashes like this Metz. The latter cost several £100 while this LED ring light costs a mere £30. A ring flash will provide a significantly more powerful light, making it suitable for a wide variety of scenarios in particular as a fill light for portrait photography. While the LED ring light is very bright to look at, it is only really powerful enough if used fairly close to the subject, for example, in macro photography.
To get an idea of its power, I did a couple of test shots, First of all, just a boring shot of a cutting mat, positioned 10 cm from the camera. The ambient light provided an exposure of 4s @ f/8 + ISO 400 (left hand image); With the ring light on, the exposure was much more satisfactory 1/320 sec @ f/8 + ISO 400 (right hand image). NB the colour difference here is primarily due to different white balance – the ambient was approximately tungsten, while the ring light is approx flash.
The second test was done using a slightly more interesting subject – a dried fruit Christmas decoration
To evaluate light falloff, I made a variety of exposures with different camera <-> subject distances. Starting at a distance of 8cm, ambient light provided an exposure of 20 secs @ f/29 + ISO 400; With the ring light on, the exposure was 1/60 sec @ f29 + ISO 400. Moving the camera out to 20cm from the subject, the ring light provided an exposure of 1/30 sec @ f/29 + ISO 400. Moving further out to 30 cm, the ring light provided an exposure of 1/10 sec @ f/29 + ISO 400.
From these figures you can see that if you tend to use tiny apertures (eg f/64) and fast shutter speeds (eg 1/200 sec) at the same time, then this light probably isn’t sufficiently powerful on its own, unless you are willing to raise ISO and work very close to the subject. On the plus side, since it provides a continuous light source, this ring light greatly facilitates focusing, arguably making it more useful than a ring flash for macro work. My take away from the test shots is that this product provides a great general purpose light source for macro work. In scenarios where it isn’t powerful enough on its own, it could be paired up with an off camera flash, the ring flash serving as illumination for focusing & the fill light, and the flash serving as the key light. For the price point, IMHO, you can’t go wrong using this LED ring light for macro work.