Dive Light Instead of Strobe?

Hi All,

While looking for a dive light I've came accross the following:

Brightstar

The picture shows some SLR with two light connected to it and there is a set of filters and diffuser available.

The question is does somebody have an experience with this kind of setup? Is this a worthly replacement for the strobes?

Thanks

I have seen a few people do this effectively for creative reasons. And I know a couple of compacy shooter who do this on all their dives. But in general torches are not as bright as strobes and the technque is hard to get good results with.\

Furthermore because divelights and ambient light are both continuous light sources both are influenced by shutter speed and aperture. So it is difficult to control their relative intensities in the final images. Strobes are not (really) effected by shutter speed - so it is easy to differentially control the levels of strobe and ambient illumination.

Alex

I have seen a few people do this effectively for creative reasons. And I know a couple of compacy shooter who do this on all their dives. But in general torches are not as bright as strobes and the technque is hard to get good results with.\

 

Furthermore because divelights and ambient light are both continuous light sources both are influenced by shutter speed and aperture. So it is difficult to control their relative intensities in the final images. Strobes are not (really) effected by shutter speed - so it is easy to differentially control the levels of strobe and ambient illumination.

 

Alex

Thanks Alex,

So, in another words, given the higher output power (~100w) of strobe against the power of divelight (~20w) and ability to control it, will provide the more space for creativity then this setup?

For example: the pictures with the dark background during the day wouldn't be possible with this setup...

To add to what Alex mentioned above, that technique has the most chances to be effective at dawn, dusk, or night for the reason he mentioned.

.............

 

So, in another words, given the higher output power (~100w) of strobe against the power of divelight (~20w) ...........

The two terms Watts (dive light, common light bulb) and Watt Seconds (underwater strobe) are similar in a way, but definitely not interchangeable. They are two distinct ways (W, Ws) for measuring. Watt measures work (joules) per second. In other words, the appliance must be on for one full second before the final reading is taken. A Watt second is a unit of measurement equal to the same amount of work as represented by a Watt. But the amount of time it may take to achieve the Watt second is not part of the discussion.

For instance. Say a strobe and a dive light both emit equal amounts of light energy, say 20 watts of power. But say the strobe is capable of doing it in 1/250 second whereas the divelight takes 1 full second to achieve an equal effect. The strobe in this example would be rated for 20ws and the dive light 20w. One light source took a fraction of a second to achieve the result, the other a full second. But otherwise the end result was equal.

So in the given time period (typical shutter speeds for capturing underwater images) the underwater strobe is relatively much, much more powerful.

One final example. If a divelight emits 20 watts in one full second and you set your shutter speed for 1/40 second, you will capture 1/40th of 20, or only a half a watt.

So at 1/40 second, when strobe is set at full dump, it actually becomes a difference between 100 vs 0.5.

hth,

b