580EXII & 270 EXII nothing built in for wireless operation so need 2 flash triggers?

I have a 5DMKII with 580 EXII and 270 EXII (the new one which can be used as a slave).

First I thought I needed only 1 transmitter and 1 flash trigger.
I have put the master 580 EXII on a trigger and the 270 EXII I turned on the slave button.
The 580 EXII flashes wirelessly but not the 270 EXII, seperately they both flash on the trigger.

First I thought there was a sender built in the 580EXII, that sent wiressly a signal that the 270EXII slave would also flash automatically, but I guess i'm wrong and need 2 triggers ?

I use this one:
http://www.benl.ebay.b​e …motes&hash=item​4ab4d1b823

The master/slave relationship between the 580EXII and the 270EXII is a proprietary Canon system as described in the flash manuals.
When you take the 580EXII of camera, unless via TTL cable or radio system, it is a manual flash and doesn't support the Master/Slave communication.
So, yes, you need a trigger on the camera and the a receiver for each flash.

There are several kinds of wireless flash triggers.

The basic triggers, like you appear to have, only fire the flash. You have to manually set power and zoom on each flash and each flash needs to be connected to a trigger.

There are the much more expensive E-TTL radio triggers. These allow you to use flash off camera and still use the E-TTL system to set flash power automatically. Most also have some way of remote manual power adjustment. You still need a trigger for each flash and a transmitter for the camera.

Canon flashes can also communicate using the Canon IR/optical system. This works well indoors with reflected light off walls and ceilings, but requires direct line of sight outdoors. I don't think any of the radio trigger manufactures allow you to use your 580EX II as a master in the Canon wireless system when connected to their E-TTL radio trigger. They want you to buy another radio trigger for the slave.

You can get a 30 ft E-TTL cable from OCF or FlashZebra and run it to the 580EX II. Then it is just like the 580EX II was on your Camera hotshoe. You can use the 580EX II as a master to control your 270EX II. You should be able to use the menus on your 5D II to control the flashes when you use a long E-TTL cable. You can use your flashes either in E-TTL mode or you can manually set power from the camera menu.

mikeca42 wrote in post #14103636
You can get a 30 ft E-TTL cable from OCF or FlashZebra and run it to the 580EX II. Then it is just like the 580EX II was on your Camera hotshoe. You can use the 580EX II as a master to control your 270EX II. You should be able to use the menus on your 5D II to control the flashes when you use a long E-TTL cable. You can use your flashes either in E-TTL mode or you can manually set power from the camera menu.

+1 ... this would be my suggestion as well.