Built-in flashes in cameras are never powerful enough for any real use, except in emergencies, or as a source of fill-in light. The E-1 does not have an internal flash at all (it wouldn't fit a "serious" camera, and, besides, it would be hard to weatherproof). In either case, most of us will need an external flash unit.

This article gives the basic information of using an external flash with S-System cameras, including the E-510, E-410, E-500, E-330, E-300 and E-1. I'll be referring to both Olympus and third-party, non-dedicated models.

External flash units can be divided into five major groups; let me follow this division in my write-up.

One: Dedicated Olympus flashes

These provide full integration with the TTL flash metering of the camera (the "TTL Auto" mode), also adding (except for the FL-20) other niceties. Another two fully-integrated units by Olympus, intended mostly for close-up and macro work, are described in a separate section at the end of this page.

The older Olympus FL-40 flash presents a more complicated situation.

• It is well integrated with the E-1, providing TTL exposure automation and motorized zooming; the only missing option is that of high-speed (multi-burst) synchronization, but most users will never notice that.
• It does not work in TTL auto with the any other Four Thirds cameras, behaving as just a thyristor automatic flash (see Group Three below), albeit a good one. Unfortunately, it also blocks the camera's built-in unit (even in the E-300, where newer flashes don't), so both cannot be used simultaneously.

Two: Dedicated units by other makers

Some independent manufacturers offer flashes supposed to support Olympus data interchange standard; most achieve the goal by providing interchangeable, camera-specific interface modules for their units. Un the past I have checked such flashes by Metz and Promaster, with positive results.

Things are not so simple, though. With the E-1, Olympus changed the interface standard: new flashes work with older cameras, but not vice versa. This means that a third-party flash which worked fully integrated with the E-20 or C-5060WZ may, and probably will not, work in the TTL mode with E-System cameras.

Frankly speaking, I haven't researched this subject, so I cannot offer any specific information. If you want a third-party dedicated flash, make sure that the maker explicitly states its full dedicated capability with the E-Sstem cameras more recent tham E-1, otherwise you may end up with a non-dedicated, thyristor unit. (Those also are capable of good results without too much effort, but why pay extra for a "dedicated unit" then?)

Anyway, do not ask me about compatibility of any specific model — I just don't know.

Three: Non-dedicated, auto-exposure units

These units will synchronize with the camera, but with the light metering done by the flash itself, using its own, external sensor. The camera has to be set to manual exposure mode, with the aperture as required by the flash and any speed up to 1/320 s (the official Olympus high-speed limit is 1/180 s, but I was able to verify the 1/320 s with the E-300, E-500, and E-510).

Most of currently available third-party, non-dedicated flashes belong to this group, and you can get a working flash solution for as little as $20, or a quite sophisticated, two-burner one for just $80.

Flashes in this group I've tried with the E-300 include FL-40 by Olympus (with the E-1 it belongs to Group One, see above), the tiny Sunpak DS20, and a flash with the inventive name of 92ATBSZ sold as a house brand by Adorama. Once again, treat these just as examples, as all of current thyristor models should also work fine with the E-300 or E-1.

In all cases, the voltage visible on the flash synch contacts is recommended to be not more than 10-12V. While Olympus says the circuitry is safe to use with voltages up to 250V, I wouldn't risk it. (If a flash was made in the last six years or so, the chances are that it will be of the low synch voltage type, but you may use a voltmeter to check.)

Four: Non-dedicated, manual

These will also synchronize OK, but are not capable of exposure metering; the camera has to be set to manual exposure mode, with any speed as above, and aperture — calculated by dividing the flash guide number (GN) by distance.

There are very few flashes of this type recently made (except for some specialized ones for professional use), so I don't think you will come across one.

My warning above, regarding the trigger voltage, is also applicable here!

Five: Totally incompatible

These may be flashes dangerous to use because of high synchronization voltage (see above), or incompatible for any other reason (I find it hard to think of one).

If you come across a flash unit (not advertised as Olympus-compatible, that is) with extra pins in the foot (besides the central, usually bigger one used for triggering), do not try to use it. It was designed for another camera line, and the extra pins are used to communicate with that camera. In the best case they will be ignored, with less luck they may damage your camera's circuitry.

Appendix: Olympus macro flash units

Note: as opposed to the above, I haven't used either of the units described in this section. Treat it therefore as a compilation of data, obtained from Olympus literature (including user manuals), grapevine, smoke, and mirrors.

When and if I get one of these (and I'm very tempted with the ring light!), I will add more information and my impressions to this section, maybe write a separate article.

Olympus offers what seems to be a very complete and attractive macro flash system. While some of individual pieces can be bought separately, the alternatives boil down to two (not mutually exclusive) setups.

As both setups share the same controller, they are also available without it, as RF-11 and TF-22 ("s" stands, obviously for "set"). The controller, however, FC-1, is not available separately, at least not in the States. It looks very smart, and even can use the HV-1 high-voltage power pack (see the FL-50 above).

If you are ready to use one of these, you probably do not need to read this article, anyway. The Asian Olympus E-System Web site (useful, complete, easy to navigate — did they hire somebody new?) offers the full specifications and even user manuals. Going through those made me quite impressed; I would love to try one of the macro units out!