Meike MK-RC7 Wireless Flash Trigger Review

Update 6/18/11: resolved problem with remote shutter function.
Update 6/8/11: identified problem with remote shutter function -- see below.
Update 5/13/11: Tried using the MK-RC7 to trigger an Alien Bee B1600. It worked 100%.

The Meike MK-RC7 is an inexpensive radio trigger that works both as a flash trigger or a remote shutter release.  It shares many similarities in function and appearance with the Yongnuo RF-602, which has been out for almost a year now (differences are marked with an asterisk):

- 2.4 GHz.  Theoretically less prone to interference.
- Receiver unit can trigger either a flash or a camera's shutter release.
- 16 channels.  *Unlike the RF-602, if the RC7 transmitter is switched to channel 1111, it will trigger all channels.  I personally would prefer not to have this 'feature'.  If someone within the range of the RC7 (100m claimed) uses this channel, your flash will be triggered and there's nothing you can do to stop it.
- *The RC7 transmitter and receiver are both powered by AAA batteries, making it easier to find replacements in the field.
- *The RC7 transmitter includes a locking pin.  To lift the pin, you push a button on the back of the transmitter.
- *When functioning as a shutter release, the RC7 has a bulb mode and a delay mode.

I bought one transmitter, and two receivers, and here's a quick review.  Disclaimer: I'm not an experienced strobist.  My review is based on my experience with other a Cactus V2s triggers and a couple of wireless shutter releases.

PARTS / WHAT'S INCLUDED:
1. Transmitter (marked "TX").  The transmitter has no on/off switch.  For the shutter release function, the transmitter has a shutter release button that can be half pressed, as well as a switch for either a) standard/bulb/continuous shooting or b) delay mode.  There is a 2-stage LED light, which lights up green when the shutter is half pressed, then lights red when the shutter is fully depressed.  There are 4 switches to choose from among the 16 channels. There is a PC sync port.  The hotshoe is made of metal and looks like it has 8 pins in addition to the two lock pins (presumably so it can work with multiple camera brands).  There are two lock pins, which can be lifted when a button behind the hotshoe is pressed.

2. Receiver (marked "RX").  The receiver has a power switch.  It must be held down for about 3 seconds in order to turn the unit on, though can be turned off with a simple button press.  The receiver has a shutter that can be half-pressed just like the transmitter.  As with the transmitter, there are 4 switches to choose from among the 16 channels. The hotshoe has 6 contacts (3 large and 3 small), and two holes for locking pins.  There is a plastic cold shoe with a hole for a 1/4-20 tripod mount.  At the top are two LEDs.  The one on the right indicates whether power is turned on.  The one on the left is a 2-stage LED that indicates whether the receiver is receiving a signal (green then red, just like the transmitter's 2-stage LED).  The receiver has a 3-pin port that looks proprietary.

3. Cable from receiver to camera (to allow the shutter release function).  One end has the 3-hole proprietary connection for the receiver.  The other end is specific to your camera make and model.

4. PC sync cable (push-in type).

5. Cable from proprietary port to phone plug.

6. Adapter from phone plug to miniplug.

I ordered another receiver and they provided an extra set of the phone plug cord and miniplug adapter (but not an extra shutter cable).

BUILD QUALITY:
My initial impression of the build quality was positive.  I had Cactus V2s trigger, and the build quality on this one appears to be a notch above that.  It's not perfect though.  For example, I found the battery cover on one of the receivers to be unusually hard to close.  So much so that I'm concerned that the small clip that keeps the lid closed might break off in the future.

FUNCTIONS TESTED:
I tested the following functions:

• Reliability as a wired cable release.
  
• Reliability as a wireless remote shutter.
  
• Reliability for triggering a single flash.
  
• Maximum sync speed.
• Wake-up function.
• Reliability for triggering two flashes. 

1. Reliability as a cable release.
An RC7 receiver can be attached to a camera to act as a cable shutter release.  Specific cables must be ordered depending on your camera make and model.  The receiver has a shutter release button that can be half-pressed and fully pressed, just like a camera shutter.  This function works even with the receiver turned off or batteries are removed.

I tested this function and did not observe any problems.  Works as advertised.

• If the RC7 shutter is half-pressed, it will function in the same way as the camera's shutter button being half-pressed.  Fully pressing the RC7 works the same way as fully pressing the camera shutter.
• If the camera is in continuous shutter mode and the RC7 shutter is held down, the camera will fire continuously.
• If the camera is in bulb mode, and the RC7 shutter is held down, the camera will fire in bulb mode and keep the shutter open for as long as the RC7 button is held down.

2. Reliability as a wireless remote shutter.
This is similar to the functionality of a cable release except that the shutter is triggered wirelessly.  The receiver has to be turned on of course.  This function works as advertised almost all of the time, but I wouldn't say 100%.  Differences from the cable release mode:

• If the camera is in bulb mode, and the receiver is also in bulb mode, the shutter will remain open for as long as the RC7 transmitter shutter is held down, except that if the RC7 shutter is held down for about 3 seconds before release, then the shutter will remain open until the RC7 shutter is again fully depressed and released. 
• Out of several trials, I observed one error in the bulb mode.  I held the RC7 shutter down, which kept the shutter up, and when I pressed the button again to close the shutter, the receiver didn't respond.  When I immediately pressed it again, the receiver worked as normal.

3. Reliability for triggering a single flash.
An RC7 transmitter can be attached to the camera either via the hotshoe, or attached to a camera or flash via a PC sync cord.  In the latter case, my camera's PC sync is disabled when I raise the popup flash.  Also, when the SB-800 is functioning as a CLS slave, the PC sync is also disabled.  The PC sync does work when attached to the SB-800, and the SB-800 is functioning as on-camera flash, CLS master, or SU-4 remote.

An RC7 receiver can be attached to a flash in at least a couple of ways: either through the flash's hotshoe or through the supplied cable for a phone plug or miniplug (like that on a Lumopro LP120 or LP160). I don't have any flash or strobe with a plug like that so I couldn't test that.

• I tested the RC7 with a Nikon SB-800 and a Yongnuo YN-560.  The RC7 worked fine with both units at ordinary shooting distances.  I did not observe any missed syncs (i.e., each time I fired, the flash sync'd).  I did not test range.  I did test through a glass door and the flash still fired.
  
• When a receiver is attached to a YN-560, the YN-560 blocks the receiver's power button (this is also an issue with the Yongnuo RF-602). An SB-800 does not block the power button.
• When a receiver is triggered, the left LED stays green for several seconds as a visual indicator that the flash was successfully triggered.

4. Maximum sync speed
The highest sync speed I was able to use was 1/250 (transmitter mounted to camera's hotshoe; flash connected to receiver via hotshoe).  The camera allowed me to choose a higher sync speed but at 1/320 the rear curtain was visible in the top fifth or so of the image.


When the transmitter is attached to an SB-800 via PC sync, the highest sync speed I got was 1/200.

5. Wake-up function.
Some flashes go into standby after a period of inactivity.  The RC7 is supposed to be able to 'wake up' the standby flash and I tested this function.  On an SB-800, the receiver was able to wake up the SB-800 which had gone to standby, albeit after one missed shot.  Alternatively, I was able to wake up the SB-800 by pressing the shutter release on the transmitter.

6. Reliability for triggering two flashes.
In this setup, the transmitter was on the camera's hotshoe.  The receivers were attached to an SB-800 (in manual mode) and a YN-560.  When I first got the units, using this setup, I had missed syncs on perhaps a third or so of trials, which gave me a bad impression of the product.  However, I've been testing it now and have found it to be more reliable, with a failure rate of 1/30 for each receiver (a success rate of about 96.67%), i.e., the probability of both receivers working is around 93.44%).  Assuming other receivers have the same failure rate as my samples, then the probability of success for all receivers are:

• 1 receiver: 96.67%
• 2 receivers: 93.44%
• 3 receivers: 90.33%
• 4 receivers: 87.32%
• 5 receivers: 84.41%

OTHER NOTES:
The flash was triggered without input on a few occasions.

As I continue using these triggers, I will post an update from time to time.  As long as you don't see anything here, you can assume they're working :)


6/8/11 update:  The flash triggering has been working consistently for triggering both speedlights and an Alien Bee monolight.  On the other hand, I had been having problems using the remote shutter function of the MK-RC7.  When I half-press the transmitter, the camera would focus but when I press the transmitter button all the way, the shutter doesn't release even though the LED on the receiver confirmed that it was receiving the signal.

With some testing, I found out that the problem was with the remote shutter cable.  If the cable is bent a certain way, the shutter does release and works normally.  I've ordered a new cable.

If you are having a problem with the remote shutter function and want to see if the cable is the problem, here's how to test it: connect the receiver to your camera and turn them both on.  Set the transmitter to the bulb/continuous shutter mode, then hold down the transmitter button for a few seconds.  Both LEDs on the receiver should light up red and stay lit.  Switch the camera to continuous shutter mode.  Then move the cable around various positions.  You may find that at certain cable positions, the shutter will be released.  (In my case I found that if the cable was bent almost 180 degrees near the receiver's port, the shutter would fire normally.)  When you're ready to cease testing, press the transmitter button again to deactivate the continuous shutter.

6/18/11 update: I received the new remote shutter cable and I tried it out.  The remote shutter worked as normal again.