1DsM2 + 100 mm + DS-125 technique

I will be doing some UW photography for the first time in Tobago with totally new equipment: 1DsM2 + 100 mm + DS-125 in the Subal housing. I understand from reading posts in this forum that manual settings with maximum aperature (16 to 22), shutter to help freeze motion (1/60 to 1/125).

What sort of settings will work for the DS-125? What is the best configuration for this strobe?

Any special environmentally sound technique to make sure you capture good macro digital photos, i.e., bouyancy, stabilizing, getting close to the subject?

Thanks,

Tom

Hi Tom,

At ISO100, I'm guessing that you'll want to use your strobes on 1/2 or full power w/ diffuser. You'll just have to try it and see. If you need to make minor adjustments, just bump your f-stop up or down. On your first or second dive, you might want to spend some time looking at the histogram (during the dive) for your shots to see if you are under or over exposing, as you can't trust the camera's LCD yet.

With all of that said, you will be diving in Tobago, so expect lots of current and in my experience from diving around Speyside, you may get frustrated trying to shoot macro in so much current and with such good wideangle opportunities.

For technique, try to tuck in behind rock ledges to get out of the current. If you find yourself getting pushed against the reef, use one pointer finger and select a dead area to push off using that one finger. Your rig is BIG and you should try to minimize drag by using small strobe arms.

Cheers

James

Hi Tom,

First of all set the camera to Manual. So that you can adjust the aperture and shutter and the camera isn't doing anything for you.

I don't know the flash synch speed of the Canon. But I would start off at the fastest flash synch setting - which I have just looked up and it is 1/250th. Then set the aperture at f16. And flash on 1/2 power. For close ups, I would place your single strobe a few inches above the port, parallel to it and pointing forward and perhaps aimed slightly down. Then get as close to your subject as you can and zap. For camera to subjects distances of about 1 foot (30cm) I would have the strobe a couple of inches above the port. For camera to subject distances longer than this I would increase the gap between the strobe and the port to reduce backscatter. If you get close to the subject you will not get backscatter.

This is not a perfect picture but it gives you an idea of what I mean.

Then using the LCD screen (+ histo if you want) just increase or reduce either the aperture or the flash power until you get the correct exposure. You will probably find you will be pretty close straight away.

Once you are on top of it, you may want to get creative and add blue/green backgrounds to your images try slowing down the shutter speed. To let the available light also come into your images.

The only other advice I'd add is to make your first dive with your housing empty -0 save some lead to weigh it down. Just so you can check that it is not leaking and you have closed it and attached the ports and synch cable correctly. To state the obvious, you don;t want to flood your 1DS as the result of a beginners mistake.

Alex

I agree with James that the currents in the NE of the island are pretty fruity. But most of the west side of the island is quiter - although not as good diving - it might make a good place to get to grips with your camera/

Thanks to the both of you for some excellent coaching. I have been disconnected from the internet for a while as the broadband service went down. I could not live without it and service was not possible until next week so I had to become cable repair man. Fortunately it all worked.

I will pool test the unit before I go, first with an empty case plus weight as you suggest. I do not want to give my 1DsM2 a bath yet. I will then try some photos at the bottom of the pool with the configuration you suggest.

I am diving with Extra Divers near Crown Point on the South side of Tobago. I believe the current is less although the clarity is less also.

Great coaching.

Tom

Another quick snippet of advice - the reflective nature of pool tiles usually means that exposures are 1 to 2 stops brighter than in open water.

Alex