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New Contributor
Posts: 2
Registered: ‎08-02-2019

Slave flash with G7X Mk II


New G7X Mk II user and first time poster with a question on using a slave flash with the G7X. Specifically, the camera came with a Vivitar SF-3000, which appears to fire correctly, but over exposes the shot.

Should the G7X be adjusting the exposure to compensate for the additional flash lighting in AUTO mode or should I be using a different mode?

Posts: 8,346
Registered: ‎08-13-2015

Re: Slave flash with G7X Mk II

You should probably be using a different flash.  List price is under $15 USD.  There is no communication between camera and flash.  Your model appears to be a slave flash that fires whenever it detects another flash going off to provide extra light.  


For the camera to control the flash output, it needs to sit on an intelligent flash shoe, which your camera lacks.


"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Valued Contributor
Posts: 481
Registered: ‎02-13-2016

Re: Slave flash with G7X Mk II

I think Wadizzle means that your Vivitar flash lacks the electrical connections (and internal circuitry) that allow your camera to communicate with and control it. There's probably 5 contacts on your camera's hot shoe for this purpose, but none at all to mate with them on your flash.

Reputable Contributor
Posts: 713
Registered: ‎12-24-2013

Re: Slave flash with G7X Mk II

The Vivitar SF-3000 has no exposure control at all. It only fires at full power and there is no control to reduce the power output. 


To get a proper exposure you will need to change the ISO, aperture, or shooting distance. It will be trial and error only. It is not a very powerful flash so start with ISO 400 and f/5.6 and see how that works.  Use Manual mode or Aperture priority so that you have control over the aperture. 


If if it is too dark, increase the ISO to 800 or change the aperture to f/4 or f/2.8


If it is too bright, decrease the ISO to 100 or change the aperture to f/8











Mike Sowsun
S110, SL1, 80D, 5D Mk III
New Contributor
Posts: 2
Registered: ‎08-02-2019

Re: Slave flash with G7X Mk II

Thanks Mike for the guidance on settings. I'll give it a try.


My main interest in using this admittadly simple flash is for fill lighting. In that regard it's missing a key feature; the ability to rotate the head upwards on the supplied bracket. You can easily swivel it to the side, but so far I've not found that as effective as pointing it at the cieling. That said, you can easily take it off the bracket and simply hold it pointed at the ceiling or if you don't want to hold it, I suppose attach it to the bracket with a rubberband so it's pointed at the ceiling.

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