Time to toss the Manual triggers? Maybe not quite, but the new YongNuo YN-622C are certainly going to shake things up, at least for Canon speedlite users.
The original YN RF-602 triggers were a breakthrough for budget reliable triggers, and the YN-622C looking set to do the same for Remote Manual, TTL and HSS triggers. We are already seeing listings as low as $75 a pair shipped. Which is less than a mid range set of manual-only triggers.
If you use speedlites at all, the convenience of remote control from the camera is really hard to overlook at this price, even if it’s just for the remote Manual control. TTL and HSS may be just a bonus.
UPDATE – June 2014 - The YN-622C-TX transmitter units are now also available to control YN-622C as receiver units. The YN-622C-TX provides a faster built in LCD interface, and also provides significant added features like the ability to mix Remote Manual and TTL groups at the same time.
UPDATE – January 2015 - YN-622C units produced after December 15th 2014 now provide direct compatibility with the remote manual YN560-TX transmitter units.
UPDATE – August 2015 - YN622C II are now available, adding a quick release lever locking hotshoe, USB port for firmware updates, and easily selectable YN560-RX mode.
UPDATE – August 2015 - YN685 Speedlites are now available, with YN-622C and RF-603 / YN-560 radio receivers built inside.
The YN-622C allow full Remote Manual Power Control, as well as HSS, and ETTL from the Canon camera flash control menu (requires camera with flash control menu and compatible flashes).
The YN-622C allow ETTL Ratios, and they have a pass through style hotshoe on top which allows flash on camera use in ETTL or Manual. As well as a basic focus assist light which works reasonably well.
Being transceiver units (both transmitter and receiver in the same unit) allows for back up transmitter units. And build quality is generally very good for the low price (though there have been some minor quality control issues at times).
YongNuo also have the advantage of having a bunch of their own inexpensive compatible flash units, even a HSS version in the YN-568EX II already selling at $105 and lower.
The one ever important omission though is the lack of USB port for firmware updates. UPDATE – USB ports are now included withe YN622C II models.
HOW WELL DO THEY WORK
UPDATE 2015 – The YN-622C have been available for a number of years now and have set the standard for inexpensive ETTL triggers. They are now easily the most popular TTL triggers currently sold.
The YN-622C where reasonably stable and reliable when first released in 2012, and with numerous software and hardware updates over the years they have improved further to be generally quite hassle free.
Providing quite complex processing (compared to simple manual radio triggers) it is still possible for the YN-622C to lose communication on occasions. And this usually just requires turning the transmitter unit on and off to quickly reboot the system before they return to normal use again.
If issues still remain then a quick Factory Reset of all the units usually resolves these. If you’re experiencing any unusual behavior a Factory Reset will often resolve those.
For the price there is no question the YN-622C are generally exceptional value. Though like anything built to a price the YN-622C production can suffer from quality control issue from time to time, so it pays to take note of the sellers return / exchange policy.
YongNuo themselves will provide 12 months warranty from date of manufacture, though you will be required to pay return shipping costs to China.
Back to 2012 -
So far all indications are very good, everything seems to be working as advertised. No misfires or random fires and range is around 50-60 meters (and sometimes more line of sight), which is generally enough.
I had one small issue from the start where the camera would not go over x-sync without a HSS flash attached, though a quick factory reset of the triggers resolved that, and no problems since. Note – If you ever do have an issue, or suspect lack of compatibility with a camera or flash etc try the Factory Reset.
The convenience of remote Manual control capability alone is really great for the price, then the ETTL and HSS are very handy too. The AF assist light is also something I have been campaigning for for a long time, and it does a reasonable decent job.
The only issues I noticed otherwise were the test fire button is not so easy to feel for on the side of the case, and you can easily bump the channel button instead putting the Tx off channel accidentally. I’m going to stick something onto the test button just so its raised a little and I can feel where it is easily.
The other thing is the locking rings are far too small and it can be hard to tighten and loosen on the camera sometimes. The 622C case is also flat on top which is not friendly to locking ring access on the pass through shoe either. That seems ok with most flash units, but placing another trigger on top for example, also with a small locking ring, is almost impossible to access.
Note – the YN622C II now resolve the locking ring issues by providing a quick release lever locking foot.
GREAT FEATURES –
- ETTL Ratios and FEC set from the camera menu (ALL/ A:B/ A:B C)
- HSS (High Speed Sync) up to 1/8000th (with compatible flash units)
- Remote Manual Power Control in 3 groups from the camera menu
- Flash On Camera in ETTL or Manual via Pass Through Hotshoe
- Mix ETTL on camera flash with manual off camera (must be set directly on flash)
- Good Focus Assist light on the Tx for low light focusing
- FEL (flash exposure lock)
- Test Fire Button on TX – Allows light meter use in remote manual
- Up to 6 stops of FEC Flash Exposure Compensation in TTL (3 stops set direct on the flash)
- Remote Flash Zoom Setting from camera (can override).
- Second Curtain Sync
- Supersync – up to 1/8000th shutter speed with studio lights (results depends on camera & lights used)
- LCD Live view triggering
- Settings saved automatically
- Transceivers means there are back up transmitter units
- Supports single contact pin camera & flash triggering, and non Canon camera use like Nikon etc
- A number of inexpensive compatible flash options
- Regular AA batteries
- 300v safe trigger voltage via PC sync cord
(NOTE – The hotshoe for speedlites is ony 6 – 12 volt safe trigger voltage)
- No USB Port for firmware updates – Resolved with YN622C II
- Canon flash control menu is not ideal (but much better than no remote control)
- ETTL Ratios set remotely are limited to 1:1, 1:2 style ratios instead of FEC via groups (like ST-E3 etc).
- Turning a group off remotely in manual power control is limited to choosing A:B or A:B:C
- Mixing ETTL and manual groups is not possible via the remote menu (can be set directly on the flash)
UPDATE - June 2014 – The YN-622C-TX transmitter units have now Resolved most of the limitations above.
- Locking rings are smaller than ideal – Resolved with YN622C II
- Channel Button is easy to bump off channel – Resolved with YN622C II
- No shutter release feature – Resolved with YN622C-TX
- Test Fire Button is Difficult to Feel.
- Low 6 to 12 volt safe trigger voltage for speedlight mounting.
(300v safe trigger voltage is also available through the PC sync port )
The functions available with the 662C do depend on camera and flash models used, and they are basically split into Type A & B Cameras (and Mark I & II style flashes).
TYPE A Cameras – with Camera Flash Control Menu
Manual – Full Remote Manual Power Control in 3 groups from the camera menu
ETTL – Full ETTL Ratio Control and FEC in 3 groups from the camera menu
1Dx, 1Ds III, 1D IV, 1D III,
6D, 5D III, 5D II,
7D, 70D, 60D, 50D, 40D,
650D T4i, 600D T3i, 550D T2i, 500D T1i, 450D XSi,
1100D T3, 1000D XS.
Powershot G12 – So far we have user confirmation the G12 will work in both ETTL (with FEC from the camera) and Manual Power Level controlled via the camera Flash Control Menu. (ETTL ratios or multiple Manual groups are yet to be confirmed).
If you can confirm functions working with any of the G series cameras please let us know in the comments. Thanks!
TYPE B Cameras – without external flash control menu
Manual – You must set the manual power level directly on the flash
ETTL – Global FEC control is available from the camera, but not ratios. Individual FEC can be set directly on each flash to achieve a ratio though.
1D II, 1D
30D, 20D, 10D,
350D XT, 400D XTi, 300D D-Rebel,
Full Remote Control
Flashes that will support remote flash control through the camera menu.
Manual – Full Remote Manual Power Control in 3 groups from the camera menu.
ETTL – Full ETT Ratio Control and FEC in 3 groups from the camera menu.
Canon - 600EX(RT), 580EX II, 430EX II, 320EX, 270EX II
Phottix – Mitros
YongNuo (with HSS) – YN568EX II, YN568EX, YN500EX
YongNuo (without HSS) – YN565EX C, YN565 II C, YN468 II C, YN467 II C, YN465 C
Nissin (with HSS) – Di866 II – may require a factory settings reset to function correctly (and in manual etc) with the 622c
Metz – 58 AF-2, 48 AF-1 (possibly AF-56 and AF-50 yet to be confirmed)
Flashes that do not support remote manual flash control through the camera menu.
Manual – You must set the manual power level directly on the flash.
ETTL – Global FEC control is available from the camera. Ratios may be available, though individual FEC can also be set directly on each flash to achieve a ratio if needed.
Canon – 580EX, 550EX, 430EX
Metz – 54mz4, 54mz3 (requires M5 firmware in the SCA foot)
Nissin (without HSS) – Di622 II
Nissin (with HSS) – Di866
Sigma – 500 DG Super, 530 DG Super
Sunpak – PZ42X – Confirmed ETTL and FEC from the camera – No HSS
The YN-622C also have a feature called Mixed Mode. This has basically 2 main functions –
Type A Cameras - this allows mixing of ETTL and Manual by allowing you to set ETTL, Manual (or Multi) on any flash, including the on camera flash, by making settings directly on the flashes themselves.
FEC from the camera will still be applied globally to any flashes set to ETTL, and you can also set FEC individually directly on each flash unit.
There is no remote Manual power control for the off camera flashes in this mode, but this is still well designed for wedding / event photographers etc who may require an ETTL flash on camera, as well as some remote manual flashes to help lift the background light in the room or create rim lights etc. The Canon menu system would not normally allow mixed ETTL and manual otherwise.
Type B Cameras – Because Type B cameras do not have a flash control menu for remote control of the flash units, they should always be set to mixed mode so that Manual power levels or FEC can then be set directly on the flashes units themselves. This also sets the camera to HSS by default so that will start as soon as you go over the cameras x-sync shutter speed.
Setting Mixed Mode - Mixed Mode only needs to be set on the 622C mounted on the camera (by holding the Channel button for a few seconds).
Setting a receiver to mixed mode allows the zoom on the flash attached to it to be set manually, separate from the camera menu zoom setting.
Its easy to see where YongNuo got their inspiration for the 662C. The case is almost identical in size to the Pixel King, except for the bulge on the one side of the King which holds that all important USB port which the 622C misses out on.
The other addition as seen below is the extra button on the side which is a dedicated test fire button, something the Kings desperately lacked. Both units have screw lock PC sync ports which are not ideal, but do the job.
Locking rings on both units are smaller than ideal, I already had to use pliers to unlock the ring to remove the trigger from the camera once. And this is more important with the YN-622C as it needs to secure a flash on top of the pass through hotshoe when mounted on camera as well.
Batteries used are standard AA and appear to be lasting well.
Note – due to their higher voltage its often best to use good Alkaline Energizer of Duracell batteries rather than rechargeable NiMH batteries.
The case is well finished and feels quite solid.
Because the YN-622C are transceivers they are exactly the same unit for both transmitter and receiver. So they have the same metal foot with TTL contacts on all units, and therefore no threaded mounting hole on the base. This means that if your umbrella swivel etc does not have a cold shoe already, you will need some form of coldshoe with threaded mounting hole in the base to attach a 5/8 stud etc.
The Frio plastic type shoes appear to be gaining popularity, I haven’t tried those but I’ve been very happy with the metal clamping coldshoes shown from flashzebra.com, or the original Stroboframe. There are some dodgy versions out there otherwise unfortunately.
Flash On Camera / Pass Through Hotshoe
The 622C have an ETTL Pass Through style Hotshoe on top which allows a full ETTL flash to be used on top mounted on the camera.
A Flash mounted on top of the 622C on camera is definitely a little more firm fitting than the Pixel Kings, but still not as neat as the Phottix Strato II for example which have pretty much set the standard for a neat fit so far.
This is important because a flash on camera with the head constantly tilted and swiveled puts a lot of stress on the trigger shoe and foot, and any movement there can quickly compound, eventually causing the TTL contacts to loose communication and become unreliable.
My personal thoughts on pass through hotshoes are (unless exceptionally well made) that they are never going to be an ideal solution for constant serious flash on camera use. But this is a really important feature for many wedding and event photographers, and given the current lack of other options (other than the high priced 600EX-RT) I think a lot of people will be giving the 622C a try.
Flash On Camera Function
There are basically 2 options here –
One option is the Mixed Mode mentioned above, where the flash on camera can be set to ETTL or Manual independently of the off camera flashes.
So for example the flash on camera could be set to ETTL, and the off camera flashes could then be used in manual to help lift the ambient light in a room. You loose remote power control of the Manual set flashes, but at least this allows mixed ETTL and Manual.
The other option is the flash on camera is simply treated as group A from the camera’s Flash Control Menu. So all flashes on and off camera can either be in ETTL or Manual, and all remotely controlled from the camera menu.
The flash on camera zoom setting is intentionally NOT controlled by the camera flash control menu so that it can be set separately to the off camera units, or set to auto to follow the lense like a regular flash on camera. Again this is well thought out for on and off camera flash use (unlike the Kings zoom function which can be hard to tame).
Flash Remote Control
The flash remote control capability of the YN-622C is determined, and to some degree limited, by the Canon flash control menu. Having been spoiled with the Phottix Odin and PocketWizard AC3 I can’t say I’m a fan of the Canon menu, but it is often better than the flash interface itself, and certainly much better than no remote control of flashes at all.
To start controlling more than one group (on or off camera) you first go to the Wireless Function and select Enable (the flash on camera will always be treated as group A) –
Manual - You can select up to 3 groups and simply adjust the manual power level of each separately in 1/3rd stops (or the graduations as set in your camera options). Three groups on would be set to A:B:C. The other options are A:B for 2 groups, or ALL to fire all groups at the same setting. One small catch here is that you can’t simply turn off say group B for example from the camera. You would need to switch the flash off itself, or possibly just wind the power right down on the camera.
ETTL Ratio – With the Canon system you really only have a ratio available between 2 groups at most (A & B). The third group C can only be a background light, if you aim C at the subject it can blow out the exposure. The group C is therefore adjusted with separate FEC.
The A & B ratio is adjusted in the old system of 1:1, 1:2, 1:4 etc. That’s pretty outdated and a bit counter intuitive compared to the ST-E3, Phottix Odins, and PocketWizard AC3 which allow you to simply adjust FEC up and down on each flash. But its certainly better than no controllable ratio like the Kings. You can actually set FEC for each flash directly on the flash itself though.
In Mixed Mode you could also create a 3 way ratio in ETTL, by setting FEC individually on the flash units themselves to first create the ratio, and then adjusting global FEC up and down from the camera as needed.
FEC – Flash Exposure Compensation
Flash Exposure Compensation is adjustable from the camera with Type A or B cameras. But FEC can also be set on the individual flash units themselves, and that will add or subtract from the camera setting. So you can get up to 6 stops of exposure compensation which can be a big help.
High Speed Sync (HSS)
FP HSS works when a compatible HSS enabled flash is attached to the 622C hotshoe on or off camera.
HSS looses a couple of stops of power, but its main purpose is for fill flash while allowing higher shutter speeds in bright ambient light, so that larger apertures can be used to blur out the background and create a nice bokeh.
ND filters can acheive a similar result with a stop or so more power, but HSS is much faster and easier to change in a fast paced environment than messing with ND filters. Good convenient variable ND filters like the Singh Ray are also not that cheap either.
Ganging 2 speedlights together often helps to retain some usable power in HSS and reduce stress on the speedlights.
HSS is not for everyone but many wedding, event, and portrait photographers would hate to be without it now, on or off camera. The freedom of selecting any shutter speed is fantastic, and the 622C certainly helps makes it more affordable off camera now too.
Second Curtain Sync
Second Curtain Sync works with the off camera flashes, but not with the wireless menu function enabled. So you no longer have remote control of more than one group. But that is still much better than no second curtain sync at all off camera (like Canons RF system).
FEL – FLASH EXPOSURE LOCK
The FEL button works when using ETTL. I find this really important for off camera ETTL as it acts like a spot meter and really lets you make the ETTL exposure decision yourself by choosing a tone in the image to meter. For people I normally just meter on the face / skin while focusing on the eyes, and its very rare for the ETTL exposure to go amiss this way even in difficult conditions.
Test Fire Button / Light Meter Use
The Test Fire Button on the 622C, like on the Pixel Kings, has a small delay, but that’s not really any practical issue. The important thing is the test button fires the flash at the correct power setting so a light meter can be used to take readings.
Another separate 622C unit held in hand (and away from the camera) can also be used to test fire all the flashes at the correct power level, even when using remote manual power settings from the camera.
Also when using remote manual power levels there is no pre flash, so you can fire the camera shutter as well to take a reading (possibly with a remote shutter release as well).
You can actually select which groups you would like to test fire at once, by scrolling through the groups while holding the test fire button. I don’t know how practical that would really be for quick light meter use though. If a light is really difficult to reach to turn off etc then it could possibly be easier switching it off like that from the Tx to take a reading .
Focus Assist Light
This is a really welcome feature, something I’m amazed the industry standard setting PocketWizard, and now even Canon has overlooked with the new ST-E3.
The AF light itself is the same as used in the YN-565EX flash unit. Its reasonably basic for centre focus point use only, but it is a pretty bright and sharp laser which projects a grid contrast pattern within a small circle, which is easily big enough to cover the centre focus point. I found it locks on focus just fine even with a 50mm F1.8 lense which has a lot of hunting for focus in low light otherwise.
You can see an example image here from the YN565ex from Speedlightes.net –
I’ve been harassing manufacturers for a long time now to make a stand alone AF light to mount radio triggers on top. Ironically a single 622C unit can also be used just for this purpose. I tried a number of manual triggers on top and they all appear to work fine. There may be a very small amount of delay added but I think this is hardly enough to see a change in sync speed (or more shutter curtain in an image).
Even without using flash the 622C can be handy sometimes on the camera hot shoe just for the AF assist alone, just shooting high iso in low light.
Forward /Backward Compatibility
The YN-622C are not currently directly compatible with any other YongNuo trigger, and no other YN triggers have been cross compatible in the past either, but YongNuo have a new engineer in charge of trigger development who has indicated that will soon change.
In the mean time though the 662C will actually work with most other manual triggers at the same time by simply mounting the other transmitter on top of the 622C hotshoe. So you can still combine your current YN triggers or most other manual ones like the Strato II shown above, or RF-602 below. So don’t be tossing those old triggers just yet!
Supersync (often know as Hypersync, which is PocketWizard’s trademark term) is a method of achieving higher sync speeds than your cameras x-sync speed with manual studio lights and speedlights. Sync speeds over the cameras x-sync are working well with manual speedlights, the timing is correct for a clean frame at any shutter speed up to 1/8000th (flash must be set at full power, and this was tested using a 1.6 crop frame camera). This is basically the standard timing so results should be similar to that of the Pixel Kings and Phottix Odin etc which also allow this feature.
Supersync with the 622C only works for lights attached to the receiver via a PC sync cord, which is a little bit of a hassle because YN do not supply a sync cord. But also triggers like the Kings and Odins conveniently allow this straight from the hotshoe with manual-only speedlights.
Note – Regular FP HSS with speedlites still works with flash directly mounted to the 622C hotshoe.
There is no adjustment for Supersync timing though (like PocketWizards) so different monolights and camera bodies will achieve different results. You will have to try with your gear and accept what you get there. This is often best with inexpensive monolights that have a long flash duration. The main advantage of Supersync is for freezing action with a high shutter speed in bright ambient light (daylight etc), which is quite difficult to achieve otherwise.
Low Battery Level Indicator
I don’t think it is mentioned in the manual, but if the battery level is low, when you enter the camera menu or half-press the shutter, the status LED will blink RED-GREEN quickly.
Hold down the [CH SET] and [GP SET] buttons at the same time until state indicators blink 3 times in red – green alternately then change to keep lighting (red), release all buttons and the factory reset is complete.
No Shutter Release
This is not uncommon with TTL triggers just due to they way they operate. The Kings or Odins do not have a shutter release function either. You can always use another trigger or wireless shutter release at the same time as the though.
2 Shooters (or 2 Cameras) – Using the Same Remote Flashes
If 2 cameras with flashes mounted on top, are set up to fire the same set of remote off camera slave flashes, there can be a problem. As they will set off each others on camera flash each time either camera takes a shot.
A work around has been found for this by simply setting the on camera YN-622C to Group C, and the off camera YN-622C to Group B.
The cameras are then both set to fire Group A:B (in ETTL or Manual) via the cameras menu .
So when one camera takes a shot, the on top flash is treated as group A (as an on top flash always is), and the remote flash is Group B.
The other cameras on top flash retains its Group C setting though, and because Group C is not enabled in the A:B firing Group set on the camera, that will not fire the other cameras Group C flash.
Of course the best method is to have a separate slave flash for each shooter (mounted on a dual flash Mulit Boom etc), and set both cameras YN-622C’s to a different Channel.
The 622C’s remote control ability is fantastic for the price, but they really don’t compare to the Phottix Odin, PocketWizard AC3 Zone Controller, (or even Canon ST-E3) when it comes to speed and ease of use through the user interface. I realise these are not in the same price range but people are often quick to look for the cheapest trigger and overlook just how much difference a good system can make. Messing with lighting can be one of the most disruptive things sometimes so it also where the biggest gains can be made as well. Once you’ve been spoiled with a good system it can be hard to go back.
The 622C are limited by Canons flash control menu, where as the Odins, PW AC3, and ST-E3 etc give you full access to the 3 groups all straight in front of you. Any one group can then be switched on or off, switched from manual to ETTL, or adjusted in FEC instead of restrictive ratios.
With the Canon flash menu you can’t even just simply turn a group off in manual, you can only select A:B or A:B:C etc. And you can’t mix ETTL and manual without loss of remote manual control.
So the Odins etc are more user friendly and fast and simple to use, the catch is they don’t allow a flash on camera like the 622C, and the Canon 600EX-RT is considerably more expensive again at this stage. That’s the tough decision people who need serious flash on camera use have been dealing with, and the 622C are going to make the decision even harder.
Any Reason to Still Get a Manual Trigger now?
I’ve been asked the question a number of times already, is there any reason not to get these instead of a good manual trigger like the (similarly priced) Strato II ? Again this can be another hard decision. The manual trigger is not really going anywhere soon, you only have to look at the latest PocketWizard Plus III to see that a good simple solid reliable manual trigger is still very desirable even if you do use them mainly with speedlights.
Manual triggers don’t send a lot of information back and forth like TTL triggers constantly do, just a quick simple fire signal. So they can be faster with sync speeds, over greater range, and using less battery power. Most can also be used as a shutter release.
But simple light meter use is often the area basic manual triggers have held the advantage, as they have no pre-flash comunications to confuse the light meter like TTL triggers often do, even in remote manual. Fortunately the 622C do not have this pre flash in remote manual either, so you can generally take a reading by firing the camera shutter, or using the test fire button on any 622C unit (even one held in hand).
The Strato II otherwise are a nicely refined design basically at the top of their class, where as the 622C are currently the cheapest in their class, a first new model, and so not as refined in physical design. The Strato have a much more solid fitting pass through hotshoe and easy to use locking rings, switches, group and channel selection. The grouping system is much more suitable for quickly taking light meter readings with different groups switched on or off quickly. And they come with all the quality cords you could need including shutter release, where the 622C don’t provide any cords.
Manual triggers like the Strato II are not going to go out of date with future compatibility issues, so they are more of an investment than the 622C which are more about maximum bang for your buck now. It really comes down to whether the remote capabilities, TTL, and possibly HSS of the 622C are what you are looking for or not, and if you have the compatible gear to make full use of them.
- YN-622C transceiver (or 2)
- 28 page User Manual & Quick Start Guide sheet
No cords or anything else are included.
In comparison the Kings come with a number of cords, batteries, stands, and a very nice padded case (which I love and still use for everything else too). But I can’t fault YN for this as most people are after the lower price point and the extras are not so important.
- System type: Digital FSK 2.4GHz wireless transceiver
- Distance: 100M
- Channel: 7
- Flash mode: E-TTL(II), Manual flash, Multi flash
- Sync mode: 1st curtain, 2nd curtain, Hi-speed sync
- Groups: 3Groups (A/B/C)
- Sync speed: 1/8000s*
- Input: Hot-shoe(TTL,main contact)
- Output: Hoe shoe, PC port
- Applicable battery: AAX2 (support 1.2 V rechargeable battery)
- Stand-by time: 60h
- Dimensions: 89.5×53×39mm
POTN Canon forum –
User Manual Online –
An altenative User Guide –
PRICE AND AVAILABILITY
Pricing is from around $80 a pair –
YN622C II Canon – Ebay
Compatible YongNuo flash units –
YN-600EX-RT – Amazon, UK, Ebay, YongNuo Ebay (Full Features, also has RT Radio Transceiver)
YN-568EX II - Amazon, UK, Ebay, YongNuo Ebay – (HSS, No External Battery Port)
YN-565EX II – Amazon, UK, Ebay, YongNuo Ebay – (External Battery Port – No HSS)
YN-500EX - Amazon, UK, Ebay, YongNuo Ebay – (HSS, 1/2 stop less power – No External Battery Port)
YongNuo – Website
YongNuo – YN-568EX Flash Review