G9 and DS-125 fires way hot

[dhaas]

El Cid,

Too much bad information not relating to your exact system operation here it gives me a headache. Jean from Ikelite has given you the best advice.

Using any brand strobe whether it is labeled "TTL capable" different than an Ikelite DS (digital substrobe) on an Ikelite TTL capable housing will NOT give you TTL flash control. Ikelite's circuitry works with Ikelite strobes for TTL.

Using "M" manual mode disables TTL on the G9 and then you're back to adjusting flash on the strobe head The mode you want to shoot that limits parameters is "Av" mode, Aperture Priority. Set your DS125 strobe head on TTL. In "Av" mode the Canon G9 is smart enough to "float" the shutter speed between a low of maybe 1/60 up to almost 1/500 a second if it thinks the background light will overexpose your photo.

Here's tips I send to get folks started and when TTL is working you will get many more properly exposed photos than guessing at manual distance, f-stop, strobe power, etc.

SHOOT in Av mode where the flash will now be TTL controlled as long as you make sure the DS125 strobe switch is on TTL. Then you only have to adjust the F-STOP for lighter or darker results initially. If you want to bias the flash up or down a bit once you find an f-stop working well at a certain distance from your subject, try this:

Under the Canon G9 "FUNC" menu you will find a choice marked + / - and a "lightning bolt" icon meaning FEC which in Canon speak is FLASH EXPOSURE COMPENSATION. You can make your flash then, IN TTL slightly darken or even lighten the flash output.

You can hook the whole system up DRY and test this so you know what icons and menus to activate.

So then in Av shooting mode, at ISO100 or 200 in tropical conditions, you only need to adjust F-STOP first (higher numbers as you shoot closer) and then if you need less flash, power DOWN the FEC as I mentioned above.....(Go towards the MINUS FLASH OUTPUT usually indicated in 1/3 amounts.)

Hope this helps

David Haas
www.haasimages.com

 

[El Cid]

I've almost exclusively used the diffuser that cam on the strobe. The only exception was when I was on a night dive, so I used the focus light as my primary light as well. Seems like, long story short, settings are manual (1/2, 1/4, 1/8 power on the light) when the camera is in manual mode, and in AV or Tv modes, the ttl capability seems to help out. The other thing I've noticed is that RAW + L setting also only works in Tv or Av modes, so I'll shoot what I can there unless I want to work out a certain effect. Thanks everyone.

First off use Manual as camera setting! Those other setting use defaults which screw up underwater exposures. No need to mess with ISO setting pick one like 200 and stick with it. Do not use Auto ISO.
In a lengthy pool session, change the strobe output incrementally by the controls on the strobe ONLY. Remember to turn power way down for macro. Adjusting strobe positon often is easiest solution. Inverse square law applies to light underwater.
Have you tried a simple diffuser on the strobe head? Translucent plastic bottle bottoms work.
goto Digital Diver.net and read up on your system there.

 

[RonFrank]

TTL should be simple. The only adjustment you should need is on the back of the housing (I assume you have +/- 2 stops like on DSLR housings). You also do your manual adjustments there (again, if it works like my DSLR).

The prevention of using TTL in M mode is IMO huge. That is about the only mode I use UW unless it is REALLY bright. Even in Bright conditions, I still tend to shoot M.

So you must shoot in either Aperture, or Shutter priority modes if using flash TTL. Does the flash being connected prevent the shutter from going below some shutter speed (like 1/60)? If so shoot in Aperture priority. If not, you will need to use shutter priority, or live with potentially blurry shots in low light. The flash duration (short) will freeze subjects, but you will get ghosting if the shutter is open for long.

I generally like to use as LEAST 1/125, a bit higher is better. I like to use at LEAST f5.6, and if shooting macro f8 is bare minimum (DSLR). Your smallest aperture maybe f8.

Honestly, you maybe best off to just shoot the whole kit in M mode, and live without TTL. You have a way to check exposures, so it's not like you can't see your results immediately. Make sure you are using your histogram to judge exposures for ALL shooting (not just UW).

When shooting UW, I generally do 1/125 and up. However the flash will freeze a subject, so that is a help. I adjust aperture to change my background, and DOF of course. For macro you want max DOF. For WA you can choose what is appropriate based on the conditions, generally fairly opened up. The trick is to try and match your settings to the ambient light if possible when shooting WA. That, or get close, and fill the frame with what ever subject you pick, and try to keep the subject to camera distance even. When shooting critters, focus on the eyes.

Good luck, and sounds like things are improving.

 

[dhaas]

El Cid,

Maybe I didn't make it clear how the Canon G9, in Av mode and an Ikelite TTL strobe attached through their housing circuitry will AUTOMATICALLY adjust the shutter speed from a LOW of 1/60 up to a faster than digital SLR can 1/500 based on water background brightness.

Here's my quote from my previous post:

Using "M" manual mode disables TTL on the G9 and then you're back to adjusting flash on the strobe head
The mode you want to shoot that limits parameters is "Av" mode, Aperture Priority. Set your DS125 strobe head on TTL.
In "Av" mode the Canon G9 is smart enough to "float" the shutter speed between a low of maybe 1/60 up to almost 1/500 a second if it thinks the background light will overexpose your photo.

SHUTTER SPEED controls background brightness, NOT f-stop! F-STOP controls foreground color and exposure from your strobe. This is primarily in wide angle photos as Ron Frank has mentioned.

The flash will freeze most underwater critter or diver motion even at the lowest TTL Av mode 1/60 shutter speed setting. But if the camera THINKS the background will be overexposed the Canon G9 will increase the shutter speed as necessary all the way up to 1/500 !

Hook everything up on dry land, set your ISO to 100 and walk outside on a bright day and shoot something at your widest zoom setting. With your DS125 lighting it up a subject 2' -3' in front of you and sky in the upper third or so of the frame you will see how this works.

It makes shooting simpler to shoot than dialing strobe power settings, individual shutter speed and f-stops in, etc.

Finally, if you want to adjust the STROBE POWER up or (more likely DOWN) than what TTL is calculating, you have to go into the Canon G9's FUNC button and scroll down to the lightning bolt +/- icon.

There are no direct FEC (flash exposure compensation) buttons the on the Ikelite housing or Canon G9 camera for that matter. Unless you set the Canon G9 "shortcut" button for that as detailed in the G9 manual.

Hook it all up dry and go test it. You'll like how it works!

dhaas

 

[Ocean Connections]

I also have a canon g9, with canon housing with an ikelite strobe, that doesn't have the circuitry,

From what I gather I should shoot in M, and adjust the strobe power and position manually for best results?

I have been shooting in Program but I like to shoot macro and had the same problem, all shots were way overexposed, i have made my own diffusor but now have problems with underexposure, i am going to try having the strobe closer to the subject when I dive tommorow.


Is it possible to use a video light to take pictures with? This would make it easier, since I like to do video with the same camera and having only one light would be easier, plus the canon case doesn't let you change the aperture once the camera is in the case, I have to decide what I want to shoot beforehand...

 

[brucetrinity]

El Cid,

Maybe I didn't make it clear how the Canon G9, in Av mode and an Ikelite TTL strobe attached through their housing circuitry will AUTOMATICALLY adjust the shutter speed from a LOW of 1/60 up to a faster than digital SLR can 1/500 based on water background brightness.

Here's my quote from my previous post:

Using "M" manual mode disables TTL on the G9 and then you're back to adjusting flash on the strobe head
The mode you want to shoot that limits parameters is "Av" mode, Aperture Priority. Set your DS125 strobe head on TTL.
In "Av" mode the Canon G9 is smart enough to "float" the shutter speed between a low of maybe 1/60 up to almost 1/500 a second if it thinks the background light will overexpose your photo.

SHUTTER SPEED controls background brightness, NOT f-stop! F-STOP controls foreground color and exposure from your strobe. This is primarily in wide angle photos as Ron Frank has mentioned.

The flash will freeze most underwater critter or diver motion even at the lowest TTL Av mode 1/60 shutter speed setting. But if the camera THINKS the background will be overexposed the Canon G9 will increase the shutter speed as necessary all the way up to 1/500 !

Hook everything up on dry land, set your ISO to 100 and walk outside on a bright day and shoot something at your widest zoom setting. With your DS125 lighting it up a subject 2' -3' in front of you and sky in the upper third or so of the frame you will see how this works.

It makes shooting simpler to shoot than dialing strobe power settings, individual shutter speed and f-stops in, etc.

Finally, if you want to adjust the STROBE POWER up or (more likely DOWN) than what TTL is calculating, you have to go into the Canon G9's FUNC button and scroll down to the lightning bolt +/- icon.

There are no direct FEC (flash exposure compensation) buttons the on the Ikelite housing or Canon G9 camera for that matter. Unless you set the Canon G9 "shortcut" button for that as detailed in the G9 manual.

Hook it all up dry and go test it. You'll like how it works!

dhaas

Exactly! .... if TTL is not working as described above, it's broken. The very purpose of TTL is to eliminate all guesswork of setting proper flash exposure. By design, it meters and sets exposure even as conditions change. Can it be a bit off one way or the other .... sure. But that's what FEC is for.