Gavin Stapleton (dpreview, Panasonic forum, 21st February 2004)...
Check out Panasonics own DMW-FL28 (F2.8,4,5.6), the Sunpak 544 handle flash (F2.8,4,5.6,8), Sunpak 383 super(F2,4,8), and Vivitar 283 auto(F2.8,4,8,11). It is difficult to find info on the FL28, but a lovely lady showed me some photos which demonstrate how user friendly it is.
The other 3 flashes have much more power, particulary the 544 which is also quite heavy and more for a prosumer. But very flexible in comparison.
The 383 (seeDan `miller342' (dpreview, Panasonic forum, 21st February 2004)...) is the most popular here, however I have concerns because it doesn't closely support the aperture range of the FZ10. Hoever it is no less effective for the people that swear by it. For ease of use I would choose the FL28, but expensive and has less range! For apeture compatibility, maybe the Sunpak 544 and Vivitar 283. IF you go with everyone else's testimony, then the 383 is for you.
My internal flash has a redeye reduction preflash -- the right joystick button activates the redeye preflash or turns it off. It shoots very nicely exposed images at exactly 5 meters wide angle and 6 meters telephoto, in Program mode. My uncles wedding shoot secret to perfect wedding pictures -- Just test and see what distance gives you a well exposed photo and use that distance for all group shots. He used a $12 fixed flash and outshot my Nikon autoflash. Every one of HIS pictures came out.
The FZ-10 has a very nice built in flash used within its distance. The trade off is weight and batteries. (I find it amazing the little fz-10 battery can record a 20 minute video clip of hula dancers and hula music! And it could have recorded longer but the music ended). Flash at full distance sucks power. That means batteries, spare bateries, maybe chargers and more weight. It's a design thing to have a light internal flash and batteriy. They have a very good external flash unit for this camera when you wish to carry the added batteries. I have a Panasonic FL28 external flash. It is rated at 32.8 feet. 10 meters.
the internal flash will expose up from the door up to the beginning of the carport, about a good size car length away. The external flashh will go about 3 times that far. One corvette length versus three. For my apartment the wall on the other side of the 2 row parking lot is well exposed.
I just shot the ground from the apartment balcony 2nd story to see how far out it would expose properly, pointed the camera at different distances and inspected the exposures.
Using telephoto (max camera zoom), the flash exposes well a little further out than with camera lens set to wide lens setting.
The flash does a very nice auto Macro mode down to about a foot by specifications, but as a test I put it almost on top of a credit card (the lens extender hood also doubles to exactly measure closest macro distance at far focus wide setting.) and the shot came out perfect. (The lens extender is a nice measuring tool for macro if you are copying from a lightbox . Just put the camera on the glass and shoot. With the card on the desk with the lens extender hood up about 1/4 inch from the desktop it was kind of like having a ring flash since it let the flashed light in from the periphery all around the lens.
If you ever use manual mode the flash has 3 aperture ranges 2.8, 4 and 5.6.
Cautions: The camera right joystick button press will prevent the flash from firing if you accidently press it. Very handy once you know it stops the flash of the external flash from firing (This same button turns the red-eye preflash on or off for the internal flash). The only indicator of why your flash isn't working is that the flash indicator has a little X through the viewfinder flash indicator when this kill feature is activated. Had to pull out the manuals to figure what I had done to turn off the flash. Since it's a camera feature it's described in the camera manual.
You can't just slip the flash on turn it on and fire when you need external flash. The camera has to be off when you put the flash in the hotshoe, and then you turn on the flash to get the camea to recognize the flash. I suspect it does a quick digital handshake. It won't hurt the camera if if you don't. The flash just won't fire.
I think the camera doesn't just trigger the flash with the single hotshoe contact but serially communicates at least the lens setting to the external flash through that one contact.Metz provides a list of their flashes which they think are suitable for the FZ10. Choose `Camera Type -> Digital', `Camera Manufacturer -> Panasonic' and finally `Mode -> DMC-FZ 10'.
CK's Digital Camera Page -- Dr. Ching-Kuang Shene's digital camera page. One of the sections listed is for the FZ10. Several of the sub-sections discuss the use of external flash, including a description about flash compatability and the FZ10's external flash hot-shoe.