how much difference does a strobe make??

[diverdeb001]

I have a bonica snapper camera which I know isn't the greatest. I am wondering if I will still get a lot of light scatter when using a strobe?? How does the strobe stop the problem or do I still need to use a marine lense with it?? db

 

[WileEDiver]

What makes an eternal strobe effective is the ability to move it farther away from the lens (through the use of extension arms). By doing this, more of the light reflected back towards you misses the aperature thereby reducing backscatter.

 

[Dee]

Wile is partly right. The strobe does need to be moved farther away from the strobe but it also needs to be aimed at an angle. This is the problem with any camera with a fixed strobe.

Let's imagine the light is a baseball, bear with me here! The strobe send out light and that light is bounced off the subject and reflected back to the camera. If that light goes straight out and straight back, as with a fixed strobe, every particle in the water will be lit and reflected back to the camera. Sort of like a catcher (camera) and pitcher (subject) throwing the ball back and forth. When the strobe is aimed at an angle, the reflection off the particles don't go back to the camera. Like the third baseman (strobe) throws to second base (subject) and he throws to first (out of bounds). The light isn't reflected directly back at the camera at homeplate so the particles aren't seen.

Clear as mud?

A friend of mine just bought a new Bonica Snapper. IIRC, the focusing distance is 2-4ft. so you'll have to stay within that distance from your subject in order for the pics to be in focus.

I would suggest if you've decided you enjoy taking U/W pictures, instead of spending more money on a very limited system, I would invest it into a digital. There are all sorts of oprions to fit most any budget. You'll get instant feedback to know if your pics are good, no more film and developing expenses and much easier to use. You have the option of simply point and shoot plus also having the ability and features available to move into more involved techniques like apertures and exposure speeds as you go....or not!

 

[diverdeb001]

Thanks Dee: I am actually thinking of the new digital camera that Sea and Sea has called the Aquapix. I have had the bonica and strobe for quite a while and haven't used it much. (never used the strobe) I've been trying to get some good pics to help me decide if i should sell it or keep it. Someone I know my be interested in buying the strobe as he has a bonica camera. thanks for you help.db

 

[Meddler]

I saw a very simple explanation of what to aim for when using a strobe.

Aim the strobe so that you minimise the amount of water that you light up between your lens and the subject.

Thats it really.

If you imagine the light coming of the strobe out as a cone, then if you point the strobe directly at your subject you will be lighting up more water in front of the lens.

If you aim the strobe so that the edge of the cone is hitting your subject then you have minimised the amount of water you have lit up. The less water you light up, the less backscatter.

The attached diagram demonstrates what I mean.

disclaimer: For me this is theory until I get a strobe but it sounds sensible to me.

 

[segal3]

No...you're trying to tie in way too many various points of information that aren't all relative.

The first setup (the one on top) is more optimal than the bottom setup...

The bottom setup is what you never really want to do usually...

~Matt Segal

 

[ReyeR]

Matt, I'm afraid I'm going to have to agree with Meddler on that - the less of water column you light up in front of the subject the less particles (backscatter) you light up in front of the subject. Both this and the explanation that Dee gave are reasons why a strobe mounted away from the lens gives less backscatter than the camera's flash.

 

[segal3]

But if you have the strobe vector parallel to the vector of the camera lens, then is not the light reflected DIRECTLY back at the camera lens?

Versus, if you have the strobe vector (aiming direction) at an angle to the camera lens, the light reflected off the particles is not reflected back to the camera, but to the location of the strobe, thus not showing up in the final picture.

Or am I missing something...

Edit - By your reasoning, the best strobe would be situated as far as possible away from the camera with an enormous angle of dispersion to produce a cone shape that just barely touched the subject.

~Matt Segal

 

[ReyeR]

By your reasoning, the best strobe would be situated as far as possible away from the camera with an enormous angle of dispersion to produce a cone shape that just barely touched the subject.

How about this setup :

(If you can't see the above image then click here: Giant Arms )

No, seriously, those light vectors that are parallel to the lens and light up particles will reflect it back to the light source in a 'narrow cone'. But because the strobe is away from the lens, say to the left, the light is not reflected back to the lens, and any from the 'narrow cone' that does reach the lens will be too weak. So moving the strobe away from the lens does 2 things: the backscatter gets directed back towards the strobe rather than towards the lens; and has the more subtle effect of lighting up less water (and hence junk) between the subject and the lens.
In reality you'll probably have the strobe positioned out to the side and above the lens. Better still, find clear water to dive in

 

[g8trdiver]

I agree also - the 2nd picture seems like the way to go. I think I've done this - accidentally. You have to be careful, though, that the subject doesn't swim outside the light cone.... that's a tricky one to gauge because there's a narrower slice of light that's optimal.

However, with the light pointing down on the subject, even with water in front of it being illuminated, it seems like depending on the steepness of the angle, the light on the particles would not ALL be reflected back to the camera. Think of the particles like little moons. Instead of getting full moons reflected back, you might have a sliver like with a new(ish) moon. Like with the WIDE brackets in the picture, the greater the angle, the newer the moon. (it's getting late.... I'm out of analogies, what can I say....)

So, compared to a built-in flash (right next to the lens - full moon), both setups would produce less backscatter. The first might be trickier to pull off with a moving subject.... but I do think it would be more effective - if you can pull it off consistently. Maybe that's why I've only done it "accidentally".