Underwater Cave Photography is hard! (2nd Trip)
Following on from my first serious attempt at underwater cave photography. I decided to play with a remote slave.
I have two Ikelite DS-125 strobes. I left one on the camera housing and set up another one with a slave sensor. My plan was to revisit Cenote Taj Mahal and check out how the slave would light up a small formation. The slave sensor I used is triggered by a flash. You can change the sensitivity of this trigger. I thought hmmmm.. caves dark so daylight wont trigger this. Surely if its set to max sensitivity it will be easier to hide maybe. Of course i was wrong. So here's what I learned about strobes in underwater caves.
1. The strobe and slave sensor have almost neutral buoyancy. This means they are both as likely to stay where I put them as my 3 year old daughter would be. Next trip with a slave I need to weight the slave or find some creative solution with the strobe arm maybe.
2. After eventually getting the strobe facing slightly upwards facing into a flowstone, hidden by some fallen stalactites, I thought I was set. The slave slave sensor was a little obviously rubber banded to one of the stalactites but who cares. maybe i could photo shop that out later. Anyway now comes the problem. As I mentioned in my previous post on underwater cave photography, Autofocus is hard. Really really hard. Now the problem is that when i move my cave light to get the focus I trigger the slave!!! take the pic and the slave is now recharging! Ahhhgggh!
I tried messing with the sensor sensitivity but it didn't help a great deal. So I finally gave up and took some random shots of this and that to get a better feeling for the XWing tie fighter focus technique.
Alter that night I found what may be the soloution. My next trip will tell. I use a Canon EOS350D digital Rebel XT. Reading in the super advanced tiny print of the manual I found a custom setting that switches focus lock from the shutter half press to the exposure lock button and visa versa.
So why is this a good thing? It means I can light the focus subject, get the focus lock and take my finger off the button now i can take an exposure with the shutter half press without the cave light and take all the time in the world. Next trip I will report on how this works out..
Most of the photos from thsi trip were pretty crappy but I did notice one quite cool effect I show in the pic below. A couple of cavern divers came by. I was up at the top of the cave and snapped a shot with a pretty slow shutter speed. The movement is quite noticable and effective. with some luck I think i could get the same shot with a better sharper subject. Time will tell!
Read the previous article,"Underwater Cave photography is hard! (1st trip)"
or the next article,"Underwater Cave photography is hard! (3rd trip)"