New strobe - basic question

[Sirto]

I just received a strobe as a present. I have a Canon A620 with the Canon housing so I will attach a fiberoptic cable in front of the flash to trigger the strobe. What I'm unclear about is what settings I need to make on the camera. I would think that the camera should be in manual mode with a fixed ISO setting but I'm unsure.

Do you shoot in full manual mode with a fixed iso and f stop and then adjust speed by trial and error to get the correct exposure or,
set camera into aperture priority mode, set iso and aperature and allow camera to adjust speed (would this work - there is no feedback to the strobe)?

So, please explain how to use the strobe since the manual is lacking any direction. If I need to set the f stop do I use the most open setting or the smallest or somewhere in between?

PS I have only three adjustments on the strobe, min, med, max power output.

 

[JackConnick]

You're going to be able to do all those things and have creative control.

You adjust your shutter speed to show more or less background, your aperture to have greater or less depth of field and your ISO to improve the range of each.

Do some experiments on dry land to give you an idea. Try to keep to one adjustment or you will be chasing it, as you gain experience you can do more.

Jack

 

[Scubakevdm]

I'm no expert, but I shoot in manual, iso 64. I don't really know alot about different kinds of cameras, and what an A620 is, but here's what I would do:

I would find something that won't move, but has some medium red or orange tone to it. I would start off with the strobe turned off, and the shutter speed set to about 125. I would take a picture of the object, adjusting the aperature until the water in the background appeared to be exposed correctly.. (on my camer, and where I dive this is around 5.6-6.3, but yours may very well be different. Anyway, when you have it right, you should end up with a dark-ish subject and nice blue (or green) water in the back ground. Next turn on the strobe, I would start low and turn it up until the subject is illuminated and colorful, but natural looking... not too bright. Strobe distance from the subject will also play a role.
Anyway, if you shoot in different directions, loke more towards or away from the sun, or if it starts raining, or if the light changes for any reason, you'll have to adjust the aperature to accomodate the light. If you find a subject that is closer or farther, or more reflective, you'll have to change the strobe power. It takes a little practice, but eventually you'll develop a pretty good feel for what your settings need to be just by looking at what you're about to shoot.