Underwater flash S2000 + Canon G7X

[soalle]

Hi all -

I am new to underwater flash photography - yet not new to [underwater] photography.

I am trying to use 2 x Inon S2000 with a Canon G7X. I do NOT have optical cables and the flash are triggered wirelessly (here it looks like they should be compatible: INON Wireless Connection Kit).

I am using this setup above water to get acquainted with it, but I am not getting the results I want/expect to see.

I have tried to set the Canon G7X to manual flash, but pictures get blown out. For the beginning I would like to stay away from manual mode.

Therefore, I set the S2000 to S-TTL and the Canon G7X onboard flash as AUTO. Pictures come out darkish, and most importantly, as I change the S2000 power output (turning the EV dial) I do not see any relevant change in the picture output, that is no change in ISO, time and aperture. To avoid any problem due to the absence of the optical cable, I have placed the flash light sensor just in front of the camera on-board flash.

(The camera *seems* not to use any pre-flash to adjust exposure but I might be wrong).

What am I doing wrong?

 

[Nemrod]

Are you sure you are in sync?

I suspect your camera is set to auto flash with no pre-flash. Though most Canons default in auto is pre-flash. The sTTL mode of the S2000 pretty sure it defaults to pre-flash expected as the only setting.

Go into your camera menu and select auto strobe with pre-flash for the camera when in auto modes such as Av/Tv. In Program I do not think you can have anything but auto strobe with pre-flash but Av/Tv are selectable for pre-flash or no pre-flash.

Stand in front of a mirror and fire the rig. If you do not see the strobes, you are not in strobe and shutter sync.

N

 

[smoore]

Not familiar with the camera but have two of these flashes. Your camera needs to be set to a forced flash mode (that is a mode that will always fire the flash. They are often labelled forced flash or fill flash). I doubt that you could visually detect the pre-flash. If you have it set to auto, then the camera will decide whether there is enough light to fire the flash or not. If it decides there is enough light, then it will not fire the flash and the Inons will not be triggered. I would think that this is what would happen most often if you fire the flash during the day above water. Nemrod is correct that the best way to test is to fire into a mirror. If you see three flashes in the picture (camera flash and both Inons), then the sync is correct. Since I do not know the camera I don't know what you need to do to ensure that the pre-flash is activated. Normally, in most cameras, the pre-flash operates in all modes except manual. Since you using S-TTL it doesn't matter whether you have the magnet inserted into the flash or not. I hope that helps.

 

[soalle]

Hi guys,

I think I could use a good help from you as I am lost. I am leaving soon for Seychelles and as of now I cannot operate the flash correctly.

I have done a test using a Olympus EM5 Mark II with flash set on AUTO.

The S2000 was also set to STTL.

I have done 3 shots facing a mirror with the second lever set to B (12 o'clock) that should be with no exposure compensation, then turning clockwise at position 3 o'clock (decreasing flash power output) and then turning it counter-clockwise at position 9 o'clock (to increase power output). All the 3 pictures came out exactly identical with no change in aperture or speed or ISO:

https://goo.gl/photos/6HyhPa4s9zaZX6Eb9
https://goo.gl/photos/2gUuEQYvhqEsTSqy8
https://goo.gl/photos/hDa32aF9L4py7A2TA

What am I doing wrong? Any help is going to be highly appreciated!

 

[smoore]

I am not sure what you are doing wrong. Since you can see the flash we know it is firing (although I cannot see the flash firing on the camera). However, it doesn't look right. I would have expected to see a very bright image of the flash with reflections and glare so this suggests that it isn't quite in synch or the settings are for significant underexposure. I think the later is more likely the problem.

Even though the flash is firing the flash mode on the camera is wrong. It should be set to fill rather than auto. If it is set to auto, then the camera will only fire the flash when it thinks there is insufficient light. In fill mode it will fire every time and that is what you want. If you don't want to fire the flash for a single or group of pictures, then you can set the flash mode to no flash.

However, this doesn't explain your problem. We know the flash is firing because we can see it in the mirror but if the picture was properly exposed (it is clearly underexposed in the 3 pictures), then the flash would be much brighter. I would suggest the following. Set the camera to P mode with no exposure compensation in a normally lit room (you want the picture to be properly lit even if the flash does not fire). Set the flash mode on the camera to fill and the strobe to STTL. See if you get correct exposures first and then try the flash compensation on the Inon and see if it makes a difference.

Next put the camera in manual mode and the flash in manual (the magnet needs to be installed in the Inon). Set the exposure for a properly exposed image in manual mode. Then install the flash and do the test again. This is to ensure that the camera works in manual mode.

It appears that you are doing these tests without using the housing and a fibre optic connection. I have never done them this way but it should not matter.

One last comment. I am surprised that I can see the flash from the Inon but not from the camera flash. I would think that both should be present but I have never done the test out of the housing and the flash window on the housing is blocked when I do the test. I cannot explain this.

Good luck and if this still doesn't work post again and maybe one of us can figure out what is going wrong.

 

[soalle]

Thanks a lot for the detailed reply. A few further info:

- the on-camera flash cannot be seen in the picture as it was tilted to point upward directly towards the Inon light sensor
- I have done a similar test (not in front of the mirror though), with camera P program, ISO 200, no exp. compensation and camera flash set to fill in. Results are similar to the ones in front of the mirror.

I have not tested yet the manual mode, but I'll try and report the results.

I am afraid that it might be a problem due to the lack of fiber optic cables...

 

[smoore]

I don't think the lack of fibre optic cables is the problem. As I suggested before I don't think you have synch problem but rather an exposure problem. I note that in the pictures it appears that the room is darkened. Were you able to properly expose pictures in that room without the flash? Also try the test with the S2000 shut off. If this doesn't lead to a properly exposed picture with the camera flash pointed at the mirror, then I would think the flash is not the problem but rather something to do with the exposure. Then turn on the S2000 and leave the camera flash pointed at the mirror (I suspect that the S2000 will still flash) and see if that is properly exposed. You should be able to see both flashes in the mirror. Try these and let me know the results.

I have the same camera and S2000 flashes. If I get an chance I will try the same thing with my camera and flashes.

 

[smoore]

Soalle I think everything is actually working fine. I tried to do exactly what you were doing in a darkened room and with normal room lights on and a I got very similar results. I have always left the flash in B on my Olympus cameras and when I needed to adjust compensation I have used exposure compensation on the camera. I can see why you might want to adjust compensation on the flash if you were getting consistently underexposed or overexposed shots using the strobes or if you were doing close macro work (possibly). I have always understood that the STTL compensation is to allow you to match the STTL to your camera rather than something that you will play with a lot when shooting. I suspect that the problem is that the flash is in the picture and is so bright that any compensation cannot be detected. When you are shooting on a dive the flash will be out of the picture. Try exposure compensation (without the mirror) and see if you get the differences in compensation you were hoping for.

 

[soalle]

Thank you so much for having carried out the tests.
I still believe there is something strange in the behavior. I was away for the past day and a half. I'll try to perform some further tests tomorrow or latest Tue. I'll report the results.