Issue with SL961 and Canon S90

[JenFid]

Hi everyone, my first post on the forums here (although I've been a frequent lurker) so bear with me if you could

I recently decided I'd like to get a simple camera for underwater photography...I was originally planning on getting something like a SeaLife mini, just cause it was cheap and I wasn't looking for anything too fancy. However at our diveshop yesterday I found a used setup - a Canon S90 with the SL961 strobe and WP-DC35 housing for $400. Everything in great condition and apparently the strobe was just replaced under warranty.

So I was tinkering with it last night. I downloaded the instruction manual and ran through the setup.

The problem I'm having is the strobe is not flashing with the camera. The strobe test flash goes off fine so I assume it must be and issue with the fiber-optic cable? I have a couple ideas of what might be wrong, but I don't know anything about this stuff so I may be way off base.

The velcro on the camera housing that covers the flash for the f/o doesn't seem to cover the flash very well. When the camera's flash is up, about half of it is uncovered. Since the velcro is circular and the housing isn't, it doesn't seem to be a very good fit. The original owner tried to modify by cutting a corner out but it doesn't seem to help. Here's a pic.
http://i31.photobucket.com/albums/c375/Verlorenkoh/IMAG0651_zpsqmpvojon.jpg
Ive tried positioning the f/o over the piece of the flash of uncovered and just holding it there while I take a test pic, but no difference.

Perhaps this one is my fault, but the manual tells you how you can remove the f/o cable from the strobe. I did so, but now that end of the cable won't stay in even when screwed tightly. A light tug and it just pops right out. If the cable is meant to be able to be removed though, I'm not sure how I could have busted it Perhaps the original owner had it glued in there?

The part of the f/o cable that attaches to the housing has a clear part sticking out of the black. Is this OK? It's a very small amount, perhaps the width of the white of a fingernail.

Any help would be greatly appreciated, I think I've exhausted my options through Google at this point. Here is a pic of the whole setup
http://i31.photobucket.com/albums/c375/Verlorenkoh/IMAG0654_zpsdpfhdfcu.jpg

 

[Interceptor121]

For P Tv A modes set strobe to pre-flash for M set to no pre-flash

 

[KeithG]

The Velcro connector on the housing is a non issue with regards to getting the flash to fire. It does not need to cover the flash, it simply needs to hold the end of the fibre cable so that the light from the flash can be delivered to it. From your pic it looks like the cable will be positioned properly.

The cable being "loose" on the strobe should also not affect triggering. As long as the light is being delivered to the strobe it should be able to detect it. Being so loose that it falls out is just a mechanical issue. It would be annoyingly md should eventually be dealt with.

You indicate the strobe was just replaced via warranty. Maybe the settings on the strobe have not been adjusted properly for this camera? It may still be in default factory settings which are likely sealife camera specific.

 

[JenFid]

Thank you both! It must have been the pre-flash setting that was causing the issue as I had it cranked up to 4. I turned it down to 0 and poof, it started flashing with the camera

 

[KeithG]

Good news!

Be aware that if you change the mode of the camera, you may need to adjust the strobe preflash setting to match it.

 

[diversteve]

The velcro on the camera housing that covers the flash for the f/o doesn't seem to cover the flash very well. When the camera's flash is up, about half of it is uncovered.

You don't want that. The idea of using the SL961 is to get the flash off the same focal plane as the camera lens thus reducing backscatter in your shots. Since the camera flash "light" is still visible, you might still get some.

Some people but black tape on the inside of their housing to minimize this. Just cover any areas that the black fiber optic holder (why it's black) doesn't. The problem will be that black electrical tape doesn't stick particularly well to plastic.

This system is one option: INON Technical Guide [Clear Photo System] It's basically a piece of blacked out exposed film in a holder. The film being dark doesn't let the light pass through but it does allow the infrared portion that triggers your SL961 to do so. Since it sticks to the camera, there's no flash bouncing around your clear plastic housing. IDK why Canon didn't mold them in black - probably so that people could check for leaks I guess...

Reef Photo sells it. But they may not have the kit for your camera any longer. Posssibly one of the other kits will work since many on-camera flashes are of similar size. Seriously overpriced at $20. A buddy uses one - it really works. All you see is sort of a dull glow thru the film.

Check with them to be sure that I'm right and it will work with your flash also. My buddy uses Inon strobes.

 

[JenFid]

Thanks, I was wondering about that. I'll start with electrical tape and see how it goes. Hopefully I'll get a chance to play around with it a bit when we do our open water cert in a couple weeks.

 

[KeithG]

You don't want that. The idea of using the SL961 is to get the flash off the same focal plane as the camera lens thus reducing backscatter in your shots. Since the camera flash "light" is still visible, you might still get some.

I agree with diversteve. Now that you have the strobe working, the next step is to address sources of backscatter.

The goal is to block the flash so that it can hit the fibre cable but not leak (very much) light out through the housing onto your subject. Your picture showed that around half of the flash was still visible from in front of the housing. So it will likely provide a source of backscatter.

For masking, Any type of opaque tape is fine to use. duct tape works great. It is cheap, easy to find, easy to work with and will stick to most things. You can use it either on the inside or the outside of the housing. Outside is a real easy starting point as there is no need to open the housing for each experiment. Once you have a suitable mask in place, you can then transfer it to the inside.

You will find that you do not need to make the housing 100% light proof, so masking is easier than it first appears.