Which triggers for mainly speedlights, but with the possibility of expanding in the future ?

Any brand of TTL control will usually give you a different exposure if you simply zoom in or out on a subject since that changes the ratio of subject and background.  The only exception I know of is if the blond or bald subject is nude against a background with the same reflectivity as the subject's skin.

The only time I use E-TTL II is when the flash is mounted on the camera and the subject to camera distance is constantly changing.  I expect to have to adjust the exposure of every image individually.

Whenever the subject is stationary I use it in manual power control mode and I try to get the flash off the camera.  This way I get consistent exposures and if any change in exposure is needed during post processing I can apply the change to all the images at once.

I'm perfectly happy with my Yongnuo RF-602s but if I used more than one or two off-camera flash units or ones that were difficult to access I would certainly be looking for RF triggers that gave me remote control of the flash power.

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Living and loving it in Bangkok, Thailand. Canon 7D - See the gear list for the rest.