What the Hell have I Screwed up NOW!

[Ardy]

Hi team

did a couple of dives in Fiji last week and using manual the flashes worked well with good exposure. Turned it to Shutter priority to shoot some fish and bang! over exposed to buggery.

I used SP on my last trip in March and all was well. Can't remember changing the settings but as I do a fair amount of above ground photography I could have. Went through the settings and could not see anything obvious. BTW it was same on P (I checked it but don't use it).

Inon Z240 and SnS 110a FO cables to Oly E520.

Can supply all settings but hoping it is something I have missed.

 

[smoore]

You haven't provided much information so it is a little difficult to troubleshoot. I assume that you were shooting full manual (no STTL) in Fiji and are now shooting STTL in SP and P modes. Is it possible that the EV conrol on the flash is set for a positive compensation thus overexposing the pictures? Is it possible that you have set the flash compensation or exposure compensation on the camera to positive settings. If you have left the camera flash control in manual and the Inon flash in manual at full power, then the flash would give a full dump but the P and S modes will likely expose without the benefit of he pre-flash and will go to a lower f stop overexposing the images. I know my EPL2 will overexpose if I have the camera and flash set in that manner. I suspect that this is what might have happened as you mention that you changed to SP mode but do not mention changing the flash settings on the camera or the flash.

With the info you have provided those the immediate things that come to mind. Hope that helps.

 

[Ardy]

You haven't provided much information so it is a little difficult to troubleshoot. I assume that you were shooting full manual (no STTL) in Fiji and are now shooting STTL in SP and P modes. Is it possible that the EV conrol on the flash is set for a positive compensation thus overexposing the pictures? Is it possible that you have set the flash compensation or exposure compensation on the camera to positive settings. If you have left the camera flash control in manual and the Inon flash in manual at full power, then the flash would give a full dump but the P and S modes will likely expose without the benefit of he pre-flash and will go to a lower f stop overexposing the images. I know my EPL2 will overexpose if I have the camera and flash set in that manner. I suspect that this is what might have happened as you mention that you changed to SP mode but do not mention changing the flash settings on the camera or the flash.

With the info you have provided those the immediate things that come to mind. Hope that helps.

Thanks for that. I did a double check last night on compensations and both are set at: 2.8 - Inon and full for SnS (set to slave) which is normal for me. The camera is set to 0.0 flash compensation. Both flashes are set to TTL (sTTL Inon). What I don't understand is why would they work in manual and not in SP. The only change I have made is to the metering area where I have changed to matrix (prior centre weighted). Checked the magnet on Inon and that is down. Camera Flash is in full auto (TTL doesn't work anywhere else on Olympus). Will do some above ground shots today with another flash and see if that works if it does then it must be something in the flashes if it doesn't must be something in camera - I hope.

HOLD IT - this was my first dive with a TC-1.4 on my macro set up and maybe that is where the difference is? Will check that as well.....

 

[smoore]

The information you posted yesterday may provide some clues regarding what is going on. If I understand things correctly when you shoot in manual you are actually using the flashes in DTTL (sTTL for Inon) mode rather than full manual. If you are shooting in sTTL on the Inon, then the magnet doesn't matter. It only matters for full manual and if it was out when it should be in the flash would fire on the camera's pre-flash and your pictures would be under exposed. There are two possibilities that I see. First, it could well be the change in metering. If you are shooting in macro and the areas around the subject are dark, then the subject will be properly exposed using centre weighted or spot metering. However, if you use matrix the sensor will detect a lot of darkness and attempt to expose the entire scene correctly by increasing the exposure either by a lower f stop, longer duration flash or both. This could result in the subject being overexposed. It is relatively easy to overexpose light coloured reflective fish swimming in open water as the background is so much darker than the fish. The other possibility is that at the shutter speed you have selected for the camera cannot close down the lens sufficiently to get a proper exposure. This seems unlikely unless you are using a slow shutter speed.

I assume that both flashes are connected to the housing with separate fiber optic cables (rather than having one connected and letting the other fire as a slave of the other). Your flash settings appear to be fine. I would experiment with different metering as I suspect that this is your problem. If testing, I would be inclined to shoot an object in macro in a reasonably dark room which should mimic the conditions you shot at underwater. I would also try shooting with each flash separately and see how the exposure is and then use both flashes.

Good luck.

 

[deeper thoughts]

interesting

 

[Ardy]

The information you posted yesterday may provide some clues regarding what is going on. If I understand things correctly when you shoot in manual you are actually using the flashes in DTTL (sTTL for Inon) mode rather than full manual. If you are shooting in sTTL on the Inon, then the magnet doesn't matter. It only matters for full manual and if it was out when it should be in the flash would fire on the camera's pre-flash and your pictures would be under exposed. There are two possibilities that I see. First, it could well be the change in metering. If you are shooting in macro and the areas around the subject are dark, then the subject will be properly exposed using centre weighted or spot metering. However, if you use matrix the sensor will detect a lot of darkness and attempt to expose the entire scene correctly by increasing the exposure either by a lower f stop, longer duration flash or both. This could result in the subject being overexposed. It is relatively easy to overexpose light coloured reflective fish swimming in open water as the background is so much darker than the fish. The other possibility is that at the shutter speed you have selected for the camera cannot close down the lens sufficiently to get a proper exposure. This seems unlikely unless you are using a slow shutter speed.

I assume that both flashes are connected to the housing with separate fiber optic cables (rather than having one connected and letting the other fire as a slave of the other). Your flash settings appear to be fine. I would experiment with different metering as I suspect that this is your problem. If testing, I would be inclined to shoot an object in macro in a reasonably dark room which should mimic the conditions you shot at underwater. I would also try shooting with each flash separately and see how the exposure is and then use both flashes.

Good luck.

Of course you are right it is the matrix metering that is screwing it up. I checked it at home and it seemed OK but then the ambient light is not what it is in macro shooting. Thanks SMoore I think you have solved it. Will try again today with different subjects in the dark and see if I can replicate it.
Thanks again.....

 

[smoore]

You are welcome. It was an interesting problem to consider and I hope everything works for you.