Tips & Techniques needed for Canon SD870, blue diffuser, Inon D2000 Setup

[kaes]

I've been shooting with a Canon SD870 and DC-17 housing for the last year. I just purchased a Inon D2000 strobe, the Inon -.5 blue diffuser (that is recommended for Canon P&S cameras), and inon UWL-100 28AD wide angle lens.

I've been reading through the forums here regarding white balance, EV settings, shutter settings, etc to get "ramped up". The SD870 has limited manual controls and wanted to ask if anyone has experience, tips, techniques to try with this camera considering my new kit (strobe, blue diffuser, WA lens).

I plan to install CHDK so I can use histogram and shoot raw.

From my research, it looks like I dont really need to worry about white balance if I plan to shoot raw since I can adjust via post processing.

This may be a stupid question, but can someone explain bracketing also? Not even sure if the SD870 can shoot in that mode.

Thanks in advance for advice.

Kaes

 

[kaes]

Ok, I think my orginal post was too generic. I've installed CHDK and now have shutter and aperture priority setttings (which are not available w/o CHDK). I'll be shooting with an Inon UWL-100 28AD wide angle lens & D2000 strobe. I'm trying to understand the best way (best settings) to light up the subject in the foreground while producing rich blues in the background. Any suggestions on what aperture and shutter speed to start with? My next dive trip is to Great Barrier Reef / Coral Sea and plan to start with ISO 100, f/8, 1/125. Read I should leave aperture constant so I can dial in the need stobe setting and use shutter to produce desired background affects.

Is this a good start? Any other suggestions?

 

[scottfiji]

My next dive trip is to Great Barrier Reef / Coral Sea and plan to start with ISO 100, f/8, 1/125. Read I should leave aperture constant so I can dial in the need stobe setting and use shutter to produce desired background affects.

Is this a good start? Any other suggestions?

that's a great start, I think your approach is very good.

Scott

 

[Nemrod]

JFYI, the aperture controls the strobe exposure, the shutter speeds controls the background exposure, more or less.

There is no magic setting.

GN / f stop (aperture) = distance to subject

Example:

strobe's underwater guide number (20) / f stop (f4) = shooting distance to subject (5 feet)

The above equation is most useful for full manual control shooting. Since the D2000 has I recall 13 power levels plus full power in manual mode and an underwater GN of 20 at full power and I think the lowest setting is about GN 1.5 or so then you can rough in the GN for the intermediate settings. Assume ISO of 100. Set ISO100 in your camera.

The Inon D2000 has an External Auto Mode, set your camera in Av mode (or manual), select an f stop for the camera and then set the D2000 to External Auto mode and dial in the matching f stop. Shoot and adjust power up and down to get the desired results by tricking the strobe by dialing in a higher or lower f stop without changing the camera's selected f stop. In External Auto the Inon D2000 is controlling flash power and duration for the subject. You did get the diffuser that allows for External Auto? The sensor is the little window with the flip over shield at the four or five o'clock position on the D2000.

BTW, in auto your camera does have plus or minus two f stop bias for bracketing.

Using the above info choose a f stop and strobe setting that gives you the desired foreground exposure on the subject, choose a shutter speed that exposes the background to suit your tastes. This works because the strobe flash is barely 1/20,000 sec or such and the shutter speed is NEVER going to be that short!!!!!!! Therefore the f stop (lens aperture) acts as the light "gate" for the sensor for the strobe, the shutter speed (and lens aperture) will expose the background.

The D2000 also has a sTTL mode that should work with your camera and may be useful for macro etc.

Not saying this is a good pic but it sort of demonstrates the above method:

I fired the strobe aimed to the side to light the nearest outcrop and fish with the camera aperture set to the D2000 aperture, the shutter speed was selected by the camera in Av mode to expose the background. I should have dialed the strobe down another notch but, hey, I am trying.

N
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