20D mode settings for AF and metering

For those lucky people that have had the 20D underwater, what are you using for these mode settings. What works and what doesn't. I'd like a starting place when I get to Bonaire.

I've been using Single Shot AF. You can try the other two if your subjects fill a large portion of the frame and really are moving too fast to snap quickly enough with that. The red flash of the focus point in this mode when focus is achieved is a great indicator however.

Metering really only comes into play with balanced blue water backgrounds.

In terms of macro, you'll want a shutter speed higher than the focal length of your lens, but slow enough to allow you strobe to fully discharge. This can range anywhere from 1/100 to 1/250 or so (if you're using a DS-125, and being limited by the flash sync-speed) as a general start. Aperture and strobe control are your own variables, adjust as necessary for the effect.

I've been using either Partial (empty circle) or Evaluative (closed circle), with the center AF focus point selected. I ran some tests this weekend, and exposure metering doesn't play into flash metering on the camera whatsoever - you can control that through the custom functions (two choices: Evaluative (eTTL2) or Average - I've stuck with the former).

Typically, you'll want to underexpose your water background by 1 or 2 stops to get a deep rich dark blue, but that can vary on user preference. I don't suggest trying to use the TTL for w/a shooting. Shutter speed will vary on ambient brightness.

Take the time on your first dive or two to see what works, and how everything relates. If you've been shooting u/w previously, it's no different.

Hope this helps - we'll be waiting for the pictures

~Matt Segal

That's what I needed. Thanks.

Matt,

You stated:

"Typically, you'll want to underexpose your water background by 1 or 2 stops to get a deep rich dark blue, but that can vary on user preference. I don't suggest trying to use the TTL for w/a shooting. Shutter speed will vary on ambient brightness."

When you are shooting WA, are you using the Tv mode? If not, what mode are you using?

Thanks,

TomC B)

Well, I've been using manual mode (M) in all my dives with this camera so far. I would think that if you *were* going to use a semi-automatic mode, that you would use aperture-priority (Av), and then set the exposure to -1 or -2 (or some intermediate) for it to calculate shutter speed. You'd likely then have to use the Evaluative metering mode as well, so that it takes into account the blue around the subject instead of a partial or center-weighted measurement (that would hopefully be filled with your subject)...

Aperture priority allows you to set a given aperture that you can adjust your strobes from...if that's varying too much at any given instant it can be difficult to be changing strobe power simultaneously, especially if you don't know the aperture.

On the other hand, when shooting fast subjects (sea lions, dolphins, schooling fish), it is necessary to have some manner of control over the shutter speed...which you wouldn't have in Av.

Thus a reliance on M. Feel free to experiment with what works best for you. Either of the two modes can be used in some situations.

BTW - In terms of the modes, this is assuredly not camera specific - but perhaps manufacturer specific. Eric or Craig (as the resident Canon shooters) might weigh in with their impressions of how the Canon setups react and what they're familiar with...

~Matt Segal

Here's my wideangle technique suggestions:

If you're shooting manual, set it on the metering mode that is as close to spot as you can get :-) Put the camera in M mode. Set shutter to 1/90th and fstop to f5.6 (example).

Point the camera at a mid blue and look through the meter. The camera will tell you if it thinks you are under or overexposing. Note that in your head. Take a photo, and look at the histogram. Are you blowing the highlight side? How does it look on the LCD? Too light? Just keep all that in mind. No point dialing in exposure comp if you won't be actually using the meter, but use the info to set your SS and Fstop. This applies for "slow action" shooting.

Take a photo w/ your strobes of something close w/ plenty of blue water in the frame. If the foreground is too light, lower the strobe power. If it's too dark, and you're at full strobe power, lower your fstop and raise your shutterspeed by the same amount.

For fast action shooting, use all that you've learned from the above. Set your camera in Av mode and set fstop and appropriate Ev compensation (probably -1 or -1.5). Take a photo w/ something in the foreground using strobes and adjust power and aperture accordingly. Now you are ready for fast action. Set your strobes at rear curtain or 2nd curtain sync if you can. As long as your shutterspeed is about about 1/30th, you shouldn't see much motion blur or shake.

HTH,

I'd be happy to continue this discussion in a different thread.

Cheers

James

My brand new instruction book for my brand new 20D says that I can use the Exposure Compensation for every mode except Manual Mode (of course, I could be reading it wrong or more likely, not understanding what I am reading).

Hence, I was wondering what mode what was suggested for WA, to be able to take advantage of +/- exposure compensation. On my old Olympus, I used to set the exposure compensation to - .7 and it seemed to work very well for the big blue. I would like to duplicate that with this camera.

I will be getting it wet in a couple of weeks and the suggestions are much appreciated.

TomC

After thinking on this subject overnight, I believe that my olympus would not except EV adjustments in manual mode either. I would use the -.7 exposure compensation in Program mode. The 20D is the same way, maybe all cameras are the same.

TomC