G-11/Ikelite AF35's: Problems w. Auto-Exposure Control

[Woody_SanFran]

I'm using a Canon G-11 in the Canon WP-DC34 housing, with twin Ikelite AF35s on the tray. Above water -- in the housing, with the strobes -- the G-11 auto-focuses and controls exposure perfectly . . . i.e., you can take perfect land shots using the G-11 within the housing, set up exactly as it would be UW (i.e., with the opaque "diffusion" shield blocking the small flash of the G-11). However, for some reason the auto-exposure control on the G-11 does *not* work UW. Auto-focus is fine UW, and both the strobes fire, but the camera does nothing to limit the amount of light . . . so many shots are either over-exposed or under-exposed (which NEVER, EVER happens above ground, no matter what you do). I have tried shooting with the G-11 set in "UW" and full Auto modes -- it's the same. The only option is to vary the intensity on the strobes with the side-handle-mounted dials, and then bracket-bracket-bracket and hope you get the shot. Also, macro is impossible UW with the G-11 in the housing, though (again) it works just fine on land.

What am I missing here? Why does the same G-11 work perfectly one foot above the water, and then fail to control exposure one foot UW???

Thanks,
Woody

 

[dhaas]

Woody,

When you say you're using the opaque "diffusion" shield are you referring to the one that comes with the Canon housing?

If so it this is a DIFFUSER and ALLOWS some flash to go through it.

This will definitely confuse the Canon G11 flash to AF35 Sensors.

You need to totally isolate and block the camera's built in flash from shooting forward.

There should be some white velcro stick on attachments in your AF35 package.

Use those as detailed in your AF35 manual and let us know if this helped.

dhaas
David Haas Underwater Photography

P.S. - Shoot in Av mode and start at f5.6

ISO 200 for tropical conditions.

For macro stay back 1-1.5' and zoom in versus cramming the whole rig in closer. You can dial the f-stop down to f8.

Make sure the AF35 BACK dial is on AUTO.

Set Side Dial at maybe 5-6 and adjust up if more flash (towards 10) or down for less flash.

 

[Woody_SanFran]

David,

Many thanks -- I'll try this tonight! I didn't notice the velcro pads . . . the Canon WP-DC34 manual directs you to use the diffusion plate. I'll let you know what happens . . .

Woody

 

[dhaas]

Woody,

The Canon housing folks assume you will only use the built in flash.

Details in the AF35 manual for their WHITE velcro DEFLECTOR.

Check Ikelite's BLOG for a few articles I wrote using the Canon S90 and AF35 units.

Plus posts I did here if you search by my name.

It doesn't have to be as complicated as many posters make it seem

Good luck!

dhaas