Last month I covered a few TTL Flash options for Micro Four Thirds, and realized I neglected the Nissin di466. This predecessor is about half the price of the i40 and just a tad bit heavier weighing it at 230g (30g heavier). It’s Guide Number (how flash power is measured) is slightly lower at 33 vs 40 but the notable difference for me is:

• No High Speed Sync (HSS) aka Super FP Mode. Most m43 bodies are limited to 1/160s flash sync speed, HSS/Super FP allows a sync speed of up to 1/4000s on the EM5. This is perfect for shooting outdoor portraits where you you want to shoot at a wide aperture and need a bit of fill flash.

Other differences of the di466 vs i40:

• “Wheel lock” vs a “Quick Release” on the i40. I hate wheel locks, I have dropped and broken the plastic pieces on the hot shoe because they weren’t fully locked on. I much prefer quick release systems.
• The i40 rotates 360°. Both can tilt, which I personally find more useful… but the i40 has the added advantage of not only being able to bounce off ceilings, but walls as well.
• Recharge time is .5 second longer at full power on the di466 vs the i40 (4.5 vs 4s).
• 1.5EV Flash compensation on the di466 vs 2EV on the i40.
• Lastly, it appears that the di466 only has hotshoe ttl, and is wireless, but does not have wireless ttl. The description isn’t very explicit and perhaps someone could comment below and confirm, nonetheless here’s their description:

The wireless remote flash system of Di466 works for either analog (single flash) and digital (pre-flash) flash systems. Variable power in six steps is available.
Place the Di466 off the camera and the flash synchronizes with the master flash placed on your camera. This wireless remote flash system is called a slave flash and is often used for a creative lighting.
Use the camera’s built-in flash, the manufacturer’s original flash, or any other Nissin flash as the master flash. Place one or more Di466 flash units away from the camera.
Use multiple Di466 flash units to achieve professional images.

Keep in mind that only a few of the latest bodies have wireless control though, and TTL Radio Triggers (eg. PocketWizards) are not yet available for Micro Four Thirds.