I'm posting this to the micro four-thirds thread because there's a lot of interest here in small flashes that go well with m4/3 gear.
The Nissin i40 is a small shoe-mount flash unit comparable to the Panasonic FL360 and the Olympus FL-600R. It is conveniently sized for micro four-thirds use. It comes in versions for Nikon, Canon, Fujifilm, Sony and m4/3. Here are sizes, weights and proces:
Nissin i40 Pan FL360L Oly FL600R
3.3x2.4x3.3 2.4x4.1x3.9 2.4x4.1x3.9
7.16oz 9.07oz 8.99oz
$269 $227 $299
At $269 it’s intermediate in price between the other two (Panasonic is cheaper), a little lighter and a fair bit smaller. All three units have the same general specs: they tilt 90° and rotate 180°. They run on 4 AA-sized batteries. They all have wireless TTL slave functionality.
One big difference is that the Oly and Panny have LCD displays while the Nissin has two control dials. The dials require no power, give immediate visual feedback and require less fiddling to change settings. The advantage of the LCD, in contrast, is that it can be illuminated when you’re shooting in the dark.
I don’t have the other two units, so I can’t compare them directly. This is my experience with the Nissin i40.
In the box
The i40 comes with a huge carrying case, about the size of a Hasselblad body, and a carabiner to carry it on your belt or clipped to the outside of your camera bag. It holds the flash, a slip-on diffuser like a mini Sto-Fen Omni-Bounce, and a table mount with a 1/4x20 tripod thread. I can’t imaging using that huge case with the dainty i40, but it’s there if you want it. The table mount is useful but will stay in the studio while the flash itself goes roaming.
The flash is an awkward shape, requiring you to play camera-bag Tetris to fit it in. Here are the dimensions of the unit in direct-flash and bounce-flash positions:
Quality Control: numbers wearing off
When the i40 first came out, people complained that the painted settings on the control dials were wearing off. I wrote Nissin customer service and they assured me the problem has been solved. So far, I can say there has been no wearing-off on the unit I have, even scraping at it with my fingernail.
Controls
Nissin has gone for a very minimalist control scheme. There are only three controls: the on/off switch and two dials. The left dial sets the shooting mode: automatic, manual, TTL, optical slave, and wireless. It also controls a low-power video light by lighting a LED panel on the front, below the flash tube.
Once you’ve set the mode on the left dial, the bigger right dial lets you change power settings: manual power from full to 1/256, TTL from +2.0 to -2.0 in half-stops, and 5 video light brightnesses (the blue dots you see on the dial). LED indicators light up on the left and right of the large dial to tell you whether you’re adjusting the settings on the left (manual) or right (TTL and video) side of the dial. The LEDs are too dim to be seen in sunlight, but after a few minutes with your new unit, you won’t need them.
Having three functions share the right dial brings up a problem. In order to display everything, the zero points can’t all be the same. Here’s an example: set the left dial to manual and full power (1/1). If you change to TTL mode, you’re at -2.0 flash adjustment. Change to video mode and you’re at the dimmest video setting. Get used to changing the right dial every time you change the left dial.
The power button is also a control. In direct-flash position with the flash in the hot shoe, the flash reads the position of your zoom lens and zooms the flashhead accordingly, from 12-53mm (24-105mm 35mm equivalent). If you want to set something else, the power button manually controls the zoom position. It is extremely frustrating. You must push and hold the power button for 3 seconds to change from auto to to 24mm position, and 3 seconds again to zoom to 50mm position. Keep holding in 3-second increments to zoom to 80 and then 105mm. If you don’t hold the button long enough, you turn the unit off.
The ready light to the right of the on/off button tells you what zoom position you’re in: green for auto, purple for 24mm, red for 50mm, blue for 80mm and yellow for 105mm. There’s a handy color guide on the back of the flash when you slide the bounce card up.
A handy color reminder for the various manual zoom positions are under the bounce card
Luckily, the unit remembers its zoom position when you turn it off and on again. Very fortunately, you will almost never need to use this “feature”! The flash is smart enough to know when you flip the head up to bounce-flash mode and sets the zoom to 24mm. And it also sets 24mm when you set the wide-angle diffuser in place or use the flash off-camera.
In use
The flash feels very secure in the hot shoe. On my Panasonic GX7, it tends to stop a little short. I’ve learned to push it the rest of the way with my thumbnail until I hear a click. To remove the flash, push and hold the release button while pushing it out from the front.
Once you get it mounted, the flash is a joy to use. The head clicks into straight-ahead position, then 45° and three other clicks to 90°. It swivels left and right to 180° so you can bounce-flash whe shooting vertically or even bounce off the wall behind you. The detents are positive but easy to change. Once you get used to the control-wheel setup, everything is extremely intuitive to use.
The head zooms to cover 14-53mm (35mm equivalent 28-105mm). It has a built-in wide-angle diffuser that increases the angle of coverage to 8mm (16mm in 35mm terms). It also has a substantial, slab-like bounce panel that slides up from the head. The bounce panel is 1 x1.6 inches (25x40mm).
Here's the flash with diffuser on the 7.5mm f/3.5 Samyang/Rokinon/Bower full-frame fisheye
The bounce panel gives a little catchlight but is too small for my use. I intend to use it with a Demb Saucer Flip-it, which folds flat to 5 x 5.5” (12.7 x 14 cm), pops up into a cup shape, and can be adjusted to capture more or less of the flash.
Built-in bounce card
No, Demb isn't paying me to recommend them
Nissin advertises that the recycle time is 4 seconds or less. I can’t measure very precisely but it seemed right at 4 seconds on manual at full power with both alkaline and NiMH batteries.
This kind of fast recycle time tempts you to just bang away, but be aware that these small units heat up fast. The i40 has a protection circuit that shuts it down if it overheats. Nissin says it will shut down for 15 minutes after 20-30 rapid-fire flashes. I got 17 rapid-fire full-power flashes before the ready light began to flash red and wouldn’t continue. It took about 2 minutes before I could shoot again. At a more sedate pace of a shot every 20 seconds or so, the protection circuit never interrupted my shooting.
Flash Power
The Panasonic and Oly flashes give their guide numbers with the flash zoomed to 42mm. Nissin muddies things by listing its guide number at 105mm, where the light is more concentrated. By my testing, its guide number at 42mm, 10 feet (3 meters) and ISO 100 is 110 (30 in meters). That is almost identical to the Panny and Oly’s guide number of 118 in feet (36 in meters).
The guide number for all these units gives you a 50% gray on a gray card, but the whites look underexposed. If you expose to the right (as you should), you'll be happier opening up to a guide number of 56 (feet) or 17 (meters). I assume the other two flash units are the same.
Bear in mind that if you use the built-in flash diffuser the flash zooms to the widest-angle position and you lose the light-concentrating benefit of the zoom feature.
TTL exposure looks a tad dark with no compensation. You might want to go to +0.5 if you like to expose to the right.
The flash vignettes noticeably, which the wide-angle diffuser eliminates. But at 42mm, you lose a whopping 2 stops of light! (There would be less light loss at wider focal lengths, of course.)
Slave use
As an optical slave the i40 has two settings: Sf (slave film) for manual flashes and Sd (slave digital) for flashes that emit a pre-flash. Indoors, this mode worked fine, even when I bounced my GX7’s tiny flash into the ceiling. Outdoors, it’s mostly useless.
Wireless TTL mode uses the camera to trigger the flash through a low-power radio signal. The i40 can only be used as a slave in this mode; it cannot be the “commander.” However, other wireless slave flashes can be controlled along with it. You must set up your camera for wireless flash and use the pop-up flash or an appropriate commander flash as a trigger. The i40 works on all channels and can be set to group A, B or C.
With my Panasonic GX7, I found I could reliably trigger the flash even outdoors, even with the built-in flash pointed away from the Nissin. The built-in flash fires, so you must bounce it or shield it if you don’t want it to contribute to the lighting.
FP High-Speed Sync
I haven’t tried this yet but Nissin says it works in A, M, TTL, and wireless mode up to 1/8000 second. Press and hold the open-flash button for 3 seconds to enter or exit this mode.
Conclusion
The Nissin i40 is sized appropriately for micro 4/3 cameras. It has a lot of power for its size and a full set of features.
Pros:
Smaller and lighter than the competition
Very good power for its size
Tilts 90 degrees, swivels to 180 degrees
Dial controls are more intuitive and power-saving
Zoom control (mostly) does what you want automatically
Manual power to 1/256, TTL +/- 2.0
Built-in 5-position constant LED light for filming
Wireless operation works well with micro 4/3
Cons:
Dials must be re-set when you switch from manual to TTL
Dial indicators hard to see in daylight
Slower recycle (supposedly) than Panny and Oly competitors
Rather awkward shape makes it difficult to fit into a camera bag
Ridiculous manual-zoom controls
More expensive than Panasonic FL360L
