YS90DX/PT-0xx users, how wide is wide enough for

the velcro over the diffuser?

I've been blowing up and going over my Bonaire pics - a lot more have backscatter in them than I think should be there. Granted, the film folks were reporting serious problems too but I'm wondering if the clear casing isn't letting enough light to exit along the lens plane to illuminate this crap and reflect back to the sensor?

My piece is the 2" more or less wide piece shaped like the one that Laz diagrams in his PT-015 review. It fully covers the diffuser as well as the areas immediately above and below the diffuser.

I worked with the camera last night, dark room, white wall in front of camera as well as a floor length mirror I moved in front from time to time.

It really looked like, with the velcro in place and the fiber plugged in (but not using the YS90), that a lot of light was hitting that wall and flashing in the mirror. I also fired the flash through a rectangular cut out (about 1" larger on each side than the diffuser dimension) in some poster board and seemed to be getting a lot of light in front of the camera.

In Bonaire, I did make sure the single YS90 was as far away from the lens and pointing inwards towards the subject as the 12" Infinity arm would allow.

Just wondering, not sure what else I could do if this is a problem.

BTW, how low can you folks set your internal flash and still trip the YS90 as a slave? A post somewhere, if I recall, mentioned 5 or so being about as low; I seemed to have good success at lower levels.

Any suggestions would be appreciated. I'll cross post to digital diver and wet pixel and share anything different that comes out of those forums.

Thanks, Bill

Black electrical tape.

That's about where I'm at, black electrical tape around the inside of the case along the perimeter of the diffuser, or I may just stick the left over velcro in that area inside.

I gave a tip some time ago about setting up the internal flash as a IR slave. A few users here tried it out but sometimes the distance from the internal flash to the slave strobe was too far and the internal flash wouldn't trigger the slave. Well that is not going to be a problem for you since you are using the fiber cable. This will solve any light leak you are having. Now let me go find the old post....... Here it is. This is a link to the original thread but I will repost some of it in this thread "Slave Flash Trick"

You take a piece of unexposed but developed slide film, cut out a piece a little bigger than the cameras flash and tape it over the cameras flash with the emulsion side out. To find the emulsion take a razor blade and scrape both sides. The side with the emulsion will scrape off easily. You want the emulsion side out because your cameras flash generates heat and the emulsion will eventually stain your flash window. It will not do this if the base side (non emulsion side) is facing the flash. Use black electrical tape or any other black tape that can take a little heat to tape the piece of film over the cameras flash. Set your camera to force flash, turn on your strobes to slave setting, take a picture and poof all your strobes fire. Some visible light will show through the film that covers your cameras flash but not enough to worry about. Also you can set your cameras internal flash to its minimum setting to conserve battery power and generate less internal heat. This all works by passing IR infrared light through the piece of slide film but very little visible light. If you don't shoot any film cameras go to a good photolab and ask for a tail end of a DEVELOPED piece of slide film. Hope this helps.

Thanks for the note, that's one to think about.

Bill

The range is ok? I would be worried that near infrared would get stripped out by only a few feet of water...?

In Bills case that would not happen as he is using the fiber optic setup.