After one week of toying with my new Zeikos 680EX on my Canon 450D (XSI), I have mixed opinion about this flash. From reading other reviews, I had set my expectations pretty low on the fit and finish, bit it turns out this flash is not bad after all. Make no mistake, it is no 580EX II, but I don't think it is a poroblem for regular use. The flash is very bright, and recharge times are pretty fast with eneloop rechargeable cells. However, I find the TTL metering accuracy questionable. With E-TTL on evaluative, and Average, the flash was too bright for direct application. For shooting inside my house( focal lengths of 24mm - 105mm, distances of 6 ft - 15 ft), I had to apply -ve flash exposure compensation (between -1 & -2) to get correct exposure. The on-camera flash however did meter the exposure correctly. Bounce flash, with +2 exposure compensation gave excellent results. If you do not plan to rely on the E-TTL, and you can afford couple of test shots to nail the exposure , this flash could be very rewarding. One problem however I noticed with the flash is that the AF assist red light pattern is misaligned - This red pattern is offset & at an angle from teh center of the lens, that in most cases the pattern is projected even outside of the frame, and hence does not provide any assistance to focussing. I tried this on two other Canon bodies to make sure this is not a misaligned hotshoe on my camera, and plan to return to Amazon & get a replacement - hoping this is a quality control issue with the specific flash I received. Overall, this flash is worth the money, and once you figure out how to compensate the flash intensity & exposure, especially with bounce, can provide amazing results.
Power ( Guide number 185)
Tilt / Swivel head, allowing to bounce flash from ceiling or wall.
Short recharge time.
Camera recognize this flash as E-TTL compatible, and can sync with 1st or 2nd curtain.
Manual controls, and user settable flash power ( 7 steps)
TTL accuracy not very good, tend to over expose, need to provide manual compensation.
AF Assist beam misaligned, and hence ineffective
Could not find a compatible Stofen diffuser. ( Amazon lists Xeikos 680EX flash bundled with Stofen omnibounce MZ6 sold by Cameta Camera, so I bought the Stofen OM-MZ6 separately, only to find that it does not fit the Zeikos flash head)