ETTL on camera with 600 EX-RT, w/ manual on the off camera flash

Hi there guys,
I used to trigger the 2 580EX-II using a cord with the pc sync + Microsync. In the same time I had on the camera's (5DMIII) another 580ExII used in E-TTL.
My question is: can I have now a 600Ex RT flash sitting on my camera hot shoe to be used in ETTL and in the same time to command two other flashes that I wish to fire in manual mode? Let's presume that I will have the off the camera flashes in A or B mode.
Is this possible? If yes, how to set it?
I have came across with the Gr mode but the flash sitting on the camera's hot shoe does not seem to work in ETTL mode at all.
Many thanks for your opinions and time

The Gr mode is for radio. Your 580s will not respond to radio signals from the 600. Set your on-camera 600 to optical master mode in E-TTL. Set your remote 580s to slave mode. Hold down the Mode button on the 580s 'til M flashes on the LCD. Manual output can now be set on the 580s. You won't have remote control of the 580s but they will fire in sync with the 600 at the power you set.

To have remote manual control of the 580s with the 600 in E-TTL, you'll need to look at third party E-TTL radio triggers.

I believe you can only mix Gr modes with a post-2012 camera; I see no mention of what you are using, so I'm not sure if that has anything to do with it...

Yes, using all 600 EX-RT flashes, you can do this with a newer camera, like the 1DX or 5D Mark III. In such a case, you'd set the master on the camera to belong to one group, and that group runs E-TTL II, and the other two flashes in another group, and that group would be in manual mode. If you want different power settings for the two slaves, they would have to belong to different groups, but since you can have five groups, that's no problem.

When using the old, optical system, with which the 600 EX-RT can indeed command the 580 EX II as well, you can have three groups, but these groups don't work the same way as the new group mode. Here all flashed are in the same mode. If you use E-TTL II, then you can set a ratio between groups A and B, as well as an independent setting for group C.
You can also set all groups to manual mode. With one flash in each group, you can command them individually, so that each group has a different power setting. But they are all manual.

However, also with the old system, you can run the master in E-TTL II and have any number of slaves set to be in manual mode, regardless of the master's mode. This is called Individual slave in the 600 EX-RT, but can be done with the 580 EX II as well. Just hold the MODE button for a couple of seconds, and you enter this independent manual mode. Once set like this, such a slave will fire in sync with the master, but the power setting is done directly on the slave, as it doesn't belong to any particular group any longer, and thus doesn't get anything but the fire command from the general master/slave system. In a case like your's, you'd set the master to A+B+C mode.
This can be done regardless of whether you use the 600 EX-RT or one of your 580 EX II flashes as master. As long as you have at least one 580 EX II in there, it's optical communication only. It works with older cameras and radio communication as well, provided all involved flashes are of the 600 EX-RT type.

Gr mode is a peach if you have a post 2012 camera.

A page out of the manual.

Hmm... I don't really care for peaches

CatalinRott wrote in post #16037887
In the same time I had on the camera's (5DMIII) another 580ExII used in E-TTL.

The OP is using a 5D III.

Oh. I missed that. Thanks

To utilize the 600's Gr mode (mixing various modes all controlled from a 600 master on camera), you'll need more 600s. That's the only way, using Canon's radio system, that you can have manual control of remote 600s from the on-camera 600 in E-TTL mode (per Anders' post).

You can still do that with the 600 in the hotshoe but you won't be getting the functionality that you want, i.e., remote manual control.

From my personal experience, with the equipment you have, you can use Yongnuo YN-622C triggers to have, in a round-about way, remote manual radio control. The 622s provide a radio interface for Canon's old optical control system. You can set your master 622 to remote manual mode, set the remote 580s' power output, switch your master 622 to mix mode, and set your on-top flash (it sits on the the master 622 in the hotshoe) back to E-TTL. Sounds cludgy, but it works and can be done quickly with practice.

Guys, thanks for the answers, I need to try out the apperson850 suggestion.
The thing I want to do it's a very simple one... I want the 600EX-rt sitting on my 5DMIII to work on ETTL and in the same time to trigger two other 600EX-RT sitting somewhere in the room. Those two would be triggered on manual mode. I did not have any idea that this is possible, will test and get back to you.
Again many thanks guys.

Since you are indeed using a 5D Mark III, then that's exactly what the new group mode is designed for. It will allow you to put the master in one group, which uses E-TTL II, and the slaves in another group, which uses manual mode. Since you can have up to five groups, you can even let the two slaves reside in different groups, both manual, but then with different power settings, if you need that.

CatalinRott wrote in post #16041315
I want the 600EX-rt sitting on my 5DMIII to work on ETTL and in the same time to trigger two other 600EX-RT sitting somewhere in the room.

Now that you've mentioned you have multiple 600s, turn to page 65 of your 600's manual and have at it. I assumed from your first post you were trying to control your 580s remotely (in manual) from the 600 (in E-TTL). That could only be done optically and without remote control.

Your master 600 in the camera's hotshoe is always group A. Your remote 600s, for the purpose of setting their modes, can be group B and C. Set group A to E-TTL and groups B and C to manual.

apersson850 wrote in post #16041334
Since you are indeed using a 5D Mark III, then that's exactly what the new group mode is designed for. It will allow you to put the master in one group, which uses E-TTL II, and the slaves in another group, which uses manual mode. Since you can have up to five groups, you can even let the two slaves reside in different groups, both manual, but then with different power settings, if you need that.

Yeah, this is the setup. The back of my flash on my 5DMIII reads
Gr
A ETTL -2
B M 1/28
C M 1/128

To make sure that I have the flash on A working on ETTL I shot the same scene with -3 and +3 then with the flash on or of, it works fine. I can control both groups in the manual mode to my desire so that is exactly what I wanted to happen.
Many thanks for your support guys

CatalinRott wrote in post #16043181
Yeah, this is the setup. The back of my flash on my 5DMIII reads
Gr
A ETTL -2
B M 1/28
C M 1/128

Have a look at your camera's flash control menus - you may prefer this way of managing your setting.