Does lowering the flash output affect the picture using an underwater strobe?

If I am using an underwater strobe connected optically, not through the hot shoe, will the picture be affected? I want to lower the output of the flash to save on battery life and heat inside the case. The flash on the camera only triggers the external flash, so there will be enough light, but does the camera adjusted other settings to counter balance the output? Or is it just a dimmer switch and will not change other settings?

Thanks

My camera is a G11, if it matters

Hi, you don't say which model flash unit you are using but essentially there are two possibilities here:

1. If you are using a strobe unit which is capable of S-TTL (i.e. INON S-2000, D-2000 or Z-240) then the output of the camera flash very much determines the output from the strobe unit. In which case you will be shooting with the camera in Av, TV or Auto. INON have a system called 'advance cancel circuitry' which cleverly fools the camera's TTL operation, reduces the flash output and conserves camera power without effecting exposure. If this applies, I have an explanation document which explains 'A.C.C.' very well. I can email it to you if you PM your email address.

2. If you are using your camera and strobe manually, (whether the strobe is capable of S-TTL or not) then of course you are relying on the camera flash output to only synchronise the strobe. In which case, yes, turn the camera flash power as low as possible to conserve power and reduce heat in the housing.

Hope this helps, Tim

This quote is from http://reefphoto.com/tt/index.php?action=kb&article=7

"The same process is repeated for the exposure, with the camera flash firing and the INON strobe precisely mimicking its duration down to the microsecond. (Strobes do not vary power or intensity, only the duration of the flash. Remember, the speed of light is 186,000 miles/sec., so all of these calculations, firing and quenching occur very, very quickly.) "

So if this is correct, then lowering the camera flash will not hurt, right? This is where i am lost.

thanks

currently i have an inon 220s, but i will be upgrading to s2000 or Z-240

So you are shooting with INONs then.

The Reef quote is referring to the S-TTL function and the document I just emailed to you will explain the concept of Advanced Cancel Circuit very well. Like I said earlier. if you are shooting your G10 and strobes on manual (not S-TTL), then turn the wick right down on the camera's flash, save power and don't heat up the housing.

You'll find the S-TTL of the INONs works very, very well and using the camera's flash exposure compensation and exposure compensation coupled with the INON's S-TTL, low S-TTL or power adjustment settings you can achieve incredibly accurate exposures.

So you are shooting with INONs then.

 

The Reef quote is referring to the S-TTL function and the document I just emailed to you will explain the concept of Advanced Cancel Circuit very well. Like I said earlier. if you are shooting your G10 and strobes on manual (not S-TTL), then turn the wick right down on the camera's flash, save power and don't heat up the housing.

 

You'll find the S-TTL of the INONs works very, very well and using the camera's flash exposure compensation and exposure compensation coupled with the INON's S-TTL, low S-TTL or power adjustment settings you can achieve incredibly accurate exposures.

Thanks, that is what I was looking for my s220, I will lower the power.

But when I get a new strobe with s-ttl, I leave the flash power alone, since the preflash will control it, right? But reef photo says a strobe/flash does not use any power intensity(dimmer) only "time" to add more light, so the s-ttl inon only reads the on/off of the flash. The camera will send out a preflash, (intensity does not matter), the strobe will also fire a preflash, camera will calculate the length of time the internal flash should stay on for the picture, and the strobe will turn on then turn off with the advance cancel circuitry. So again, intensity should not matter, so I can lower it. Maybe???

thanks, excuse me for being a little dense

No. if you are shooting with an S-TTL capable strobe any flash power adjustment setting you make on the camera will be mimiced by the strobes. That's great as for most circumstances the camera is your 'one stop shop' for exposure adjustment other than tweaking each strobe individually for creative lighting control. As a general rule when shooting S-TTL with my G9 and Z-240's I set the flash exposure compensation to -1 stop and exposure compensation to -2/3 stop and adjust the exposure a nad in Camera RAW.

This quote is from http://reefphoto.com/tt/index.php?action=kb&article=7

 

"The same process is repeated for the exposure, with the camera flash firing and the INON strobe precisely mimicking its duration down to the microsecond. (Strobes do not vary power or intensity, only the duration of the flash. Remember, the speed of light is 186,000 miles/sec., so all of these calculations, firing and quenching occur very, very quickly.) "

 

So if this is correct, then lowering the camera flash will not hurt, right? This is where i am lost.

 

thanks

currently i have an inon 220s, but i will be upgrading to s2000 or Z-240

When you turn the flash down in camera, it will turn down the duration of the in-camera flash. As Tim said, this will shorten (weaken) the S-TTL flash also.

When you turn the flash down in camera, it will turn down the duration of the in-camera flash. As Tim said, this will shorten (weaken) the S-TTL flash also.

now i got it!!!, the flash is also controled in time, so when u lower the power on the flash, the time is less on the flash so the strobe also is on for a shorter time frame.

thanks to everyone!!!!

I've just found a lot more interesting information here - http://www.inon.jp/technical/sttl_advanced.html

now i got it!!!, the flash is also controled in time....

Yes, strobe output is only controlled by the time they are on for. There's no such thing as intensity variation; they are either on or off.

The Inon D2000 and the Z240 have an "External Auto" setting which is fully independent of the camera's flash setting. External Auto mode uses the built in exposure control of the D2000/Z240 to control the flash. You can alter the result by setting a different F number in on the strobe control knob vs what is set on the camera. This mode DOES NOT mimic the camera strobe, it only uses the camera strobe to trigger the D2000/Z240(in optical sync). The sTTL modes mimics the camera's strobe, External Auto does not.

When using the External Auto mode in Tv/Av or Manual it is best to set the camera strobe to manual and then set it to lowest power. This reduces heat buildup, increases battery life, reduces recycle time (for the camera) etc.

BTW, the S2000 does not have External Auto mode.

Crawdad makes a very good point. Many strobes are equipped with an 'auto' function which at ISO 100 meters the stobe output to the camera's aperture setting. The problem with 'auto' is that as the strobe's sensor needs to be pointed directly at the subject, 'edge' lighting is not possible and, therefore, backscatter becomes more pronounced.

What about working witn manual settings?

On my Nikon I can set the camera to manual strobe exposure, inhibiting the preflash, turn down the power in the camera's menu to the minimum needed to trigger my Inon strobes (Z220, Z240 or S2000), and set the strobe power independently, then correct the exposure by looking at trial exposures.

The Z220 works best in this mode as it doesn't have the sTTL compatibility of the Z240, as far as I know (the Z220 doesn't have the ACC, for instance, and I think it fires in the same way for preflash and true flash, so it will only work at relatively low power with a fast recycle time). I am experimenting with the S2000 (optical control only) for macro work, and its optical control matches the Z240, but it's probably under-powered for wide-angle.

Tim