Look Ma' - No Backscatter!

[bobf]

Sea Yoda,

What side of your rig is the external strobe on when facing the subject?

Is the fish in image #2 the same as in image #1?

b

 

[SeaYoda]

The strobe is on the left as I have the camera pointed away and in front of me. The strobe sits right on top of the handle on that side (not far from the camera) - that's why I'm working on a loc-line extension.

Yes the fish in both pics are grey snapper - they can change their color right before your eyes. They can go from a silver grey with no eye stripe to the reddish-brown color with eye stripe.

 

[RiotNrrd]

Hey SeaYoda - Nice shots!

I'm really impressed with your management of backscatter. Some questions about how you reduced it so much:

1.) Close, close, close?
2.) Low intesnity of the on-camera flash?
3.) Other?

I'm still having some issues with it, but most of my shots have been from realtively far away (3-5 feet). The few shots I've taken that have been really close have been fairly low backscatter. However, I have not tried reducing the on-camera flash that much. I have the fiber-optic cable on order.

I didn't have any trouble with the intensity adjustment on my Sunpak - just checked it again, and no problems. Are you measuring with a meter? Or just comparing the recycle time?

RiotNrrd

 

[SeaYoda]

Hey SeaYoda - Nice shots!

I'm really impressed with your management of backscatter. Some questions about how you reduced it so much:...

...I didn't have any trouble with the intensity adjustment on my Sunpak - just checked it again, and no problems. Are you measuring with a meter? Or just comparing the recycle time? ...

I don't know about your camera, but mine has a diffuser panel that I covered so the internal flash would not shoot light forward (where all the backscatter comes from in the first place). When I get the cable, I'll slip it between the housing and covered diffuser. For now, some light comes out from the open sides of the diffuser and triggers the external.

I'm not using a meter, I got into a dark room and tried a shot on high and then without changing camera settings I adjusted the strobe knob all the way to low. I saw no difference in intensity as far as the quality of the picture. I'm a little worried that my new toy may need replacing.

Can you see a visible difference in your pictures with just an adjustment to the strobe knob?

 

[PAdiver93]

Sea Yoda!

The fish are moving out??? And that's in Florida... Let's just say we have shore dive planned for Saturday - If I see anything alive other then my buddy (no pun intended) - I'll be happy... And when u r talking about shooting conditions - try shooting over here - in the pea soup...

Again great shots - for some reason I enjoy seeing non-tropical grey/black "boring" bottom feeders a lot more than the tropicals! (Look more real?!)

 

[RiotNrrd]

I don't know about your camera, but mine has a diffuser panel that I covered so the internal flash would not shoot light forward (where all the backscatter comes from in the first place). When I get the cable, I'll slip it between the housing and covered diffuser. For now, some light comes out from the open sides of the diffuser and triggers the external.QUOTE]

My camera has a diffuser, but the point of the diffuser is not to block, so much as to soften. (you may already know this, so if so, please skip). With a point light source, you get harsh shadows, so the diffuser makes it look less like a single bulb and more like a big blok of light. Think of a white cloth lampshade. This is why pro photographers use umbrellas, softboxes, etc.... so that the light is "softer." So even though the diffuser is on, you should still be getting light from the front. THis is part of why I am so impressed with your lack of backscatter!!!

I'm not using a meter, I got into a dark room and tried a shot on high and then without changing camera settings I adjusted the strobe knob all the way to low. I saw no difference in intensity as far as the quality of the picture. I'm a little worried that my new toy may need replacing.

Can you see a visible difference in your pictures with just an adjustment to the strobe knob?

Are you shotting in auto mode? Maybe the camera is compensating. Or maybe the camera just happens to have a shutter/f-stop setting that doesn't require the flash to get good exposure?

I tested mine by firing the camera with the Sunpak at full and with the Sunpak at low. Full takes the entire 9 seconds or so to recylcle, while low takes 0 seconds to recycle (i.e., the "ready" light is on immediately after the triggering).

Just to be sure, I just went and tested it with my Luna Pro. When at the lowest setting, 3 inches away, the meter says to shoot at f11. When at the highest setting, the meter says "unable to measure - too much light."

RiotNrrd

 

[SuPrBuGmAn]

Most of the northern Gulf of Florida just got over a Red Tide... Might have alot to do with the amount of fish found closer inshore. Water is still in the 80ºsF tempwise from the last reports I've heard.

 

[bobf]

Are you shotting in auto mode? Maybe the camera is compensating. Or maybe the camera just happens to have a shutter/f-stop setting that doesn't require the flash to get good exposure?

good advise Riot. And could explain what we're seeing. You have to make sure that the camera forces the flash. Rule #1.

What side of your rig is the external strobe on when facing the subject?

Is the fish in image #2 the same as in image #1?

The strobe is on the left as I have the camera pointed away and in front of me. The strobe sits right on top of the handle on that side (not far from the camera) - that's why I'm working on a loc-line extension.

Yes the fish in both pics are grey snapper - they can change their color right before your eyes. They can go from a silver grey with no eye stripe to the reddish-brown color with eye stripe.

Sea Yoda,

Thanks for answering my questions.

Now to go out on a soft coral limb...........

I'm still not convinced that the external strobe was close enough to your fish subjects to have played any role in the foreground exposure of image #1 and #3. As Riot suggested, there's also a possibility that the slave signal was not sent by the camera (set to "P") because the camera felt it could capture enough light by opening up the aperture and slowing down the shutter speed to allow enough light to hit the sensor. Another possibility is that the strobe did not see the slave signal. Another possibility is that you chose an aperture too small for your strobe's intensity setting.

You mentioned however that the snapper has the ability to change colors. I agree. Not sure however if that is why he appears so different than the snapper in image #2.

I asked about strobe placement to help explain the shadow on the skate's left side (closest to the viewer). The light appears to be coming from the left, where you say the strobe's placement was, but not sure if the angle is correct. Although it could be.

And I'm still confused by what appears to be a rainbow on the skate's back. Could strobe light leave a rainbow behind? Strobe light would have to pass through something to break it up in order to display those colors. If the rainbow were caused by the sun(you said you were shallow), wouldn't the strobe light overpower it? The reflections of sunlight found on the sea bottom also appear similar to that found on the skate on my screen.

I'm not questioning you, I'm only trying to offer "logical" alternative explanations to what I am "seeing" in your images.

If you would like to review a successful settings strategy offered by another underwater photographer, I would recommend studying Peter Schulz's offerings listed on his web site. If you set the c5050 to slave, force the flash, and shoot in manual mode, your strobe, set to slave, should perform in similar fashion to the strobes in Peter's arsenal (although different beam angles, gn, etc).

http://www.splashdowndivers.com/photo_gallery/underwater_photography/up_settings.htm

Try Peter's "My Mode 1" for starters..........

Peter always suggests testing the rig in a dimly lit room, facing a mirror. Press the shutter. If the strobe light is present in your LCD feedback display image, everything should be set to go.

Hope you find an answer for your intensity dial concerns. Keep us posted.

regards,
b
--

 

[tangfish]

The shots look terrific Yoda, keep it up!

 

[SeaYoda]

Well a couple things are falling into place with the strobe - the short of it is that I think it has a problem and LeisurePro is going to exchange it for me.

It seems as though the strobe is stuck in low power mode - it flashes but the recycle time is almost non-existent even when set to high.

The two grey snapper were that different looking. The underbelly of the "grey" one is lit up differently enough from pics I've taken before to know that it caught some flash - just not very much due to low power. The "reddish" one caught more flash and was in the shadows so even the low power showed up well.

The skate was no more than 4' from the surface - that's where the rainbow came from. I was swimming very close beside it and the low power flash just filled in some shadows.

I'm happy with even the results of the low power - I'll probably flash everything in sight when I get it to work for real .