|DCRP Special Report: SR Electronics Ring Flash Review
by Tom Beardmore (December 17,1998)
Okay, I'll admit it. I'm a detail-oriented kind of guy. I'm fascinated by the minuscule details that come to light through macrophotography, in even the most ordinary subject matter. As a case in point, just take a look at the details that you can see in this outdoor faucet timer by clicking on it.
All you need is a digital camera that either has a built-in macro mode, or one that supports a close-up lens set. If the camera permits you to preview the image directly through the lens as well (such as TTL cameras like the Olympus D-500L, D-600L, or D-620L) or by using its built-in LCD (like the Nikon CoolPix 900s and others), you've got all the basics. As long as you're working with plenty of available light, you can produce some great detailed close-ups.
Indoors, however, it becomes much more difficult (if not impossible) to get satisfactory results with most digital cameras available today using their built-in flash units. Overexposure, harsh shadows, uneven illumination, and glare all contribute to less than satisfactory results. In conventional film-based photography, the answer is to use a ring flash unit with a single lens reflex camera. A ring flash is an electronic flash unit in the shape of a ring that attaches to the front of the lens using its threaded filter mount, surrounding the lens to produce soft, even illumination of the close-up subject.
Unfortunately, the current crop of consumer digital cameras poses some obstacles to using a ring flash. Most popular digicams have no threaded filter mounts like 35 mm cameras do, so there's no place to mount a ring flash on them. Among those few digicams that do have threaded filter mounts, some of the more popular models have no external flash synch socket, notably the Olympus D-500L & D-600L (although the new D-620L has one). Without an external flash synch socket, there is no way to synch the ring flash with the camera's shutter.
Although the photographer could use a slave trigger to set off the flash ring (a slave trigger is designed to set off a secondary electronic flash unit when it detects the flash of a primary unit), conventional slave triggers fire as soon as any flash is detected. Several popular digital cameras flash twice when taking a picture: the first flash sets the exposure and white balance, but it's the second flash that is used to take the picture.
The Solution: SR Electronics RF-50
The RF-50 includes 49 mm, 52 mm and 55 mm series VII adapter rings, and a 43 mm to 49 mm step-up ring. To mount the RF-50 onto the Olympus, screw the 43 mm to 49 mm step-up ring into the threaded filter mount of the camera. Next, select the 49 mm series VII adapter ring and screw it onto the back of the RF-50. Finally, mate the RF-50 to the step-up ring on the front of the camera and screw the two together.
The RF-50 incorporates a built-in automatic exposure sensor that is effective from 1 to 3.1 feet (30 to 95 cm), so you'll find that most of your close-up photos will be perfectly exposed as long as you don't get too close to the subject; remember that the sensor is not designed to control the exposure closer than 12 inches to the subject. You can also override the sensor by switching the ring flash to the manual mode, but you'll be on your own if you do.
In order for the automatic sensor to accurately perform its function, you'll have to mount the RF-50 in a manner that blocks the camera's built-in flash unit (or find a means to otherwise reduce its intensity). Fortunately, because RF-50 has a free-rotating Series VII screw ring on the back of the unit, you can orient the ring flash in any position needed. I found that it was possible to mount it upside down on my D-600L, as shown here, so that the bulk of the unit's body was positioned directly in front of the camera's built-in flash. This is the way I used the unit in all of the example photographs that follow,
The Proof: Comparative Examples
In the pictures of the cellphone, note that the keypad's slightly curved surface produced uneven illumination using the built-in flash. In the same picture taken with the ring flash, the lighting is more even, and there is no "hot" side.
In the pictures of the thumbtacks, the example taken with the ring flash produced a less harsh image and showed better color saturation. Shadows were less apparent, and there was much less glare in the picture taken with the ring flash.
In the picture of the miniature bicycle wheel taken with the built-in flash, the shadows made it difficult to tell where the black rubber tire ended, and the shadows began. There is also a very bright reflection coming from the crank. None of these problems were apparent in the photo taken with the RF-50.
In the final example, I intentionally created a difficult lighting situation by photographing a dark subject on a dark background. The differences here were rather subtle, such as the washed-out label of the standing SmartMedia in the photo on the left. The photo on the right had better overall color saturation.
I think you'll agree that the RF-50 consistently produced better results when photographing close-up subjects than when the camera's built-in flash unit was used!
Getting Your Best Results
Having used the ring flash unit, I've developed a few tips of my own:
I also found it puzzling that the unit didn't include the flash synch cable, even though the manual indicates that one is supposed to be provided with the unit. I realize, of course, that the RF-50 is designed as a slave unit, and that it is triggered by the Olympus' own built-in flash. However, with the introduction of the D-620L, which has an external flash synch socket, and other digital cameras which have them, I think it would make sense to include the flash synch cable anyway.
So Who Would Use This?
As always, if you should have any questions about this review, feel free to drop me a line!
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