Thailand - South Andaman Sea

Started 1 month ago | Discussions thread
Dale108
Dale108 Veteran Member • Posts: 7,457
Re: Thailand - South Andaman Sea

Great series, thanks for sharing.

Dale

Barmaglot_07 wrote:

I just got back from diving South Andaman sites off Koh Lanta, Thailand. Many thanks to the crew of Kon-Tiki dive center for making this an amazing experience. The dive sites at Koh Haa, Koh Bida and Hin Daeng/Hin Muang are every bit as good as the Similans/Surin/Richelieu Rock, but don't require a liveaboard to access.

With regard to photography, I was shooting a Sony A6300 in a SeaFrogs Salted Line housing, with a Sony 10-18mm f/4 lens in an 8" dome for wide angle and a Sony 90mm f/2.8 G lens in a flat port for macro. Dual SeaFrogs ST-100 strobes, no focus light. Generic tray, arms and clamps from Aliexpress; with the dome setup, I used 4x8" regular arms and about 600g of auto wheel weights on the dome to achieve slightly negative buoyancy, while with the macro lens and port, I swapped two of the regular arms for 60x200mm carbon fiber float arms.

Anyway, enough rambling - pictures!

I ran into an odd issue with strobe triggering - the fiber optic cable sockets are located on top of the SeaFrogs Salted Line housing, and for some reason, they're offset about a centimeter to the left of the actual camera flash position. There is an aluminium reflector set at 45 degrees to direct light from the flash into the sockets, but since right right-side socket is directly over the flash, and the left-side socket is off to the side, the light needs to bounce a couple more times to get into the left socket. The ST-100 strobes are TTL-only when triggered by fiber optics, and I noticed that the strobe plugged into left socket was only firing on the main flash, not the pre-flash. I'm assuming that because pre-flash is very short, the camera flash doesn't have time to reach full intensity, and this fails to trip the strobe's trigger when the light has to bounce a few times too many on its way there. The main flash is more intense, and this does trigger the strobe, but since TTL metering is only done with one strobe and main exposure is done with two, this throws the metering off and produces overexposed images. Nothing too bad, pulling the exposure down by 0.5-1.5 stops in Capture One usually solved it, but still annoying. Hopefully UW-Technics will release their TTL trigger for Sony soon, and then I'll just put the LEDs right into the sockets and this whole thing will go away.

Another observation - the 90mm lens used noticeably more battery power than 10-18mm. With 10-18mm, I can reliably get three dives off a single fully-charged battery, but with 90mm, I was usually down to 20% or less charge after just two dives, necessitating a battery change on the boat (I was diving three tanks per day).

This was my first time shooting macro underwater (previously, I only used 16-50mm and 10-18mm lenses), and going straight to 90mm (135mm-equivalent) was kind of jumping in with both feet, but it ended up being surprisingly manageable, at least in clear tropical water. Framing was problematic at times, especially with very well camouflaged scorpionfish and such, but I honestly expected it to be harder. Focus was reasonably fast and mostly accurate - it usually hunted for a few seconds on small subjects, and snapped right in on larger ones. One thing that it kept missing though were those tiny juvenile black anemonefish - the way they dart around, the camera simply wasn't fast enough to follow; I had a couple dozen shots that ended up totally out of focus until I got one that was usable.

 Dale108's gear list:Dale108's gear list
Sony RX10 III Olympus TG-5 Nikon Coolpix P1000 Olympus E-M5 II Pentax K-1 +1 more
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