Using the SX260 HS underwater

[marshlaird]

I am having trouble preventing over-exposure using an external strobe underwater.   I'm using the Ikelite AF35 strobe, which fires when the camera's flash goes off.  I believe the Canon (in anything other than 100% manual mode) determines how it is going to expose the photo before its flash goes off, and therefore it doesn't know how much light the stobe will produce.   The strobe then produces much more light than expected, and the Canon over-exposes.

Ikelite says the SX260/AF35 combination is supposed to work, and told me to try Av mode, saying that Av mode will have a pre-flash.   I don't know how a pre-flash is supposed to help, but it doesn't work, and I don't see a pre-flash.

The only other recommendation I have gotten is to adjust the exposure 100% manually, which I want to avoid.   

Does anyone have any other suggestions?

[cicopo]

I shoot a G9 with 2 old Sea & Sea strobes that only have 1 power level so know what your hoping to do.  Your problem is very straight forward in that the camera is calibrated for it's built in flash so it picks settings based on that flash's output power. It has no way of knowing you have an additional flash (or more) nor how powerful they are so it (the camera) can't select appropriate settings. Manual is the best way to use your set up & after a bit of use you'll get used to making changes as the scene changes. You'll need to use very different settings for open water or dark coral vs a sandy bottom. Macro work will be a bit more difficult but you might be able to difuse the flash to cut it's power output or bounce it. Now this is a guess & I've never thought about trying it until thinking what to suggest but you "might" be able to use NEGATIVE Flash Exposure Compensation, but it will be better to just learn to use manual settings & to bump the ISO up or down for even more control. 

[marshlaird]

OK, thanks.  It looks like there is no way any automatic setting will work, so it looks like I'll have to learn to use manual controls.   Under dynamic lighing conditions, I think I'll be lucky if I can get the correct exposure in fewer than 6 tries  🙂

Using manual mode, of course I'll want to review each photo as I take them, to see how the exposure was.   And adjust and re-take as necessary.   Given that I'll want to review each photo --- I am quite baffled as to why the review option is not available under manual mode.  It is available under AUTO and LIVE, but not under Prog, Tv, Av or M.   WHY NOT???   Am I missing something?   The alternative is to drop out of "take photo" mode and go to "view past photo" mode (or whatever it's called).  That seems awfully time-consuming.

[cicopo]

Because I don't have or know that specific camera are you saying it doesn't display the image you've just shot for a second or 2? If so I'd read the manual very carefully to see if it's set wrong. You do need to see the photo briefly to make adjustments when you've seen whether it was over or under exposed, and after one or 2 dives you'll get good at deciding what's needed for different situations. Another way to improve your keeper rate is to shoot in RAW which gives you more latitude later for exposure corrections, plus it's really easy to get more natural colours with a simple white balance correction at the start of the editing of each photo.

Don't be intimadeted by the idea RAW processing is a lot of work because it's not & can make a huge difference to underwater photos. I use Adobe Photoshop's Camera RAW which is also included in Adobe Elements & I highly recommend it for this style of Photography. You can check my recent albums at the link I'll provide & very few of the photos took more than a minute to process. 

http://picasaweb.google.com/CozumelTimeCapsules

[marshlaird]

The camera doesn't offer RAW mode.

On the review feature, I took you up on your suggestion to study the users manual.  It indicates that the review mode is available in all exposure modes except one that I don't care about.   But it was greyed out in my menu.  I searched over and over for an option that might be overriding the review feature (and making it unavailable), but i could't find anything.  So I re-set all settings.  Voila -- I can now get a review in manual mode.  I'm off and running.

Except no RAW still.

Thanks --

[cicopo]

Too bad it won't shoot in RAW but for now at least you've solved the most important problem. Hard to evaluate what you can't see & in most cases the fish aren't going to wait while you go through the menues trying to re set & shoot again. If you get serious about your underwater photography you can shop for an upgrade which does shoot RAW down the road. Have you been diving for long? If not mastering your buoyancy is critical for good results.

[marshlaird]

I've been diving for about 16 years -- 400-ish dives in all.   I had a Canon 20D with enclosure and dome 8-9 years ago but it is too cumbersome for me -- too much for me to lug around.  I'm into small and light now.   I still use my 20D (with RAW capability) above the water.  

The SX260 is a really good little camera despite its quirks, which I am trying to iron out rather than replacing it.

On the topic of RAW ... the SX260 HS does not offer RAW, nor lots of other good features ... but I just leared that RAW and other things ARE available if you download some [MOD NOTE: Link removed per FORUM GUIDELINES] from "CHDK" -- Canon Hack Development Kit.  It's availalbe for a huge number of Canon models.  Apparently the camera hardware is capable of RAW, but Canon just doesn't make it available in its point-and-shoot models.  No telling why not, but these CHDK people have gone around Canon.   I haven't decided yet whether I'll download this stuff or not.

[cicopo]

Well I'd say you're no rookie then. I also hear you about a full DSLR rig which is why I shoot the G9 & to date it does what I want from it. I personally don't know much about the CHDK but do know someone using it on an SX50 (he's very software literate) & he seems very happy with all the new things he can do because of it.