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Cave Photography, multiple strobes


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#1 sea_ledford

sea_ledford

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Posted 24 February 2014 - 12:26 PM

I am headed to a very limited access cave (i.e. I likely won't ever be going back) in a few weeks and will be doing my first cave photography (maybe).

 

I haven't been there before, there are very few images of the cave to see what I'm in for, photography is not the primary objective and I'll have 7 dives at the max, and more likely only 3, that I'll be able to shoot.

 

So odds stacked against me from the get go, I'm looking for some advise.

 

I have a Nikon d7000 with  2 z240's on board (triggered via fiber optic), one ikelite DS125 with EV controller and two Nikonos 105's.

 

I've figured out that I can trip the 105's  (no pre-flash option) if I set the camera internal flash to manual, and if I set the EV controller correctly, it will fire the DS125 properly with out a pre-flash as well. Super excited about all that.

 

However, while testing the z240's with the camera in manual flash mode, I'm not getting any variation in power from changing the settings on the back of the strobe; full, manual at 1, manual at 11, auto, sttl.. all the same output. And I just checked, camera exposure is in manual as well. I also tried changing the flash setting in camera from full to 1/128th, no change. It all works fine if the camera is set to TTL.

 

Anybody with ideas on the manual settings?

 

I also have two Sola video2000's that I could use rather than the NIkonos strobes if they put out enough light. I could put the camera back in TTL and solve my Inon problem that way.

 

And come to think of it, will TTL even work in a cave? I'll probably end up setting the camera and adjusting the strobes manually anyway.

 

Thanks!

 

Chris



#2 errbrr

errbrr

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Posted 28 February 2014 - 10:26 PM

Sounds fun! I recommend shooting everything manually, and (if the water is clear and the cave a reasonable size) putting all your strobes on full power. Use directional aiming of your on-camera strobes to reduce over-exposure if you are close to a wall/floor/ceiling.

 

Do a dry run with your buddies first - it's hard to believe how many first time cave modellers will point the off camera strobe at you. You may like to do the dry run at night with the strobes working so you can practise model hand positions that will trigger the sensor, especially if you're using the strobe sensors on the Niks rather than something like a triggerfish.

 

Other cave photography advice:

- use your widest lens

- set your focus manually once underwater (i.e. use your dive light, focus on the model at middle distance, lock focus) otherwise you will need a large focus light for each picture which rapidly annoys your model

- Your shutter speed is irrelevant, so set and forget at a speed that works for the dive lights others are using. Adjust your ISO pre-dive to the highest you are comfortable with. Then on the dive use your f-stop to control your exposure, and worry about the lighting arrangement rather than the camera settings.

 

Stay safe. The cave is not going anywhere. Access may be tricky, but try to avoid the "this is the only chance I will ever get" mindset. That way lies danger.

 

I'd love to see the shots once you have them.