High Speed Shutter and Flash Sync / Water Drop photos S3 Is

jls3512

45

« on: 24 / February / 2012, 07:38:08 »

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Hi, I'm not only a newbie to CHDK, but also a newbie to any kind of photography, I have never really taken any pictures at all in any mode other than 'AUTO' ... so please pardon my ignorance.

I am fascinated by things like the water drop photos I've seen and other high speed shutter stop motion effects. I have a canon S3 IS camera, I've got CHDK working on it, and I can navigate the menus and see the extra photo settings that allow me to override the shutter speed, but I think I am missing something to be able to make this work. I get pictures that look basically the same no matter what I select in there. I am not sure what mode the camera should be in.. I try auto, thinking maybe the automatic settings would compensate for the high shutter speed I put in, ah, but somehow I don't think it's that simple. I try manual mode and fiddle around with it, but I really don't have a clue.. sometimes I get way over exposed completely white photos. When I set manual settings to something like ISO800 I can get photos that are in focus, but it's not really stopping the drop like some photos I've seen, and changing the high speed shutter settings only seems to be effective to a certain point, and then everything looks the same. I thought perhaps as a way to test how fast my shutter was going I could take pictures of my CRT monitor.. when I start off I get the whole screen, and as I increase the shutter speed, I start getting less and less of the screen, but it seems I can only get it down to about 1/2" wide stripe in various random positions, and never any thinner than that.. I'm not sure if it's because I'm not really overriding the shutter, or perhaps my idea is no good because the phosphor takes that long to fade out?? I have virtually no difference between shutters of 1/1000, 1/10000, 1/64000 and 1/100000

So here are my questions:
What mode do I put my camera in for this?
If it's some manual mode, how do I adjust the other parameters? I am guessing I want a high ISO
Do I have to do something to enable flash sync? or does it always sync?
is there a setting somewhere for flash duration or flash sync speed? I can't figure out how to adjust the flash other than with the canon flash power settings in the original menus. I set it on minimum power thinking that would be the fastest.

If someone would be kind enough to explain the procedure for this, I would greatly appreciate it!

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outslider

762

Re: High Speed Shutter and Flash Sync / Water Drop photos S3 Is

« Reply #1 on: 24 / February / 2012, 08:30:36 »

The best idea is to be in manual mode. You have to set shutter speed at level 1/5000, maybe 1/10 000 to catch a drop (worked for me).

You probably need to use flash light, or other very bright light. But the flash is the best (for me). Of course aperture number must be as low as possible (to avoid confusion with names - better is 3.4 than 4.0). With high ISO you'd need less light. Powershots might give high noise on high ISO though.

If you not see any difference between 1/10 000 and 1/40 000 then 1/10 000 might be something near to your camera physical limit. But if there is no difference between 1/1000 and 1/10 000 then something is wrong, not sure now, what.

Flash should be always in sync with the shutter, but maybe something is also wrong here. On my sx130 at 1/40 000 flash works perfectly.

I thing you'd need to do more experiments on manual mode...

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jls3512

45

Re: High Speed Shutter and Flash Sync / Water Drop photos S3 Is

« Reply #2 on: 24 / February / 2012, 09:59:58 »

Thanks Outslider, that gives me an idea where to start with the manual settings anyway. I will try also additional lighting, I have a nice bright LED flashlight that has it's own tripod so that would probably be easy to get positioned and stay put.

I saw somewhere while going through various posts that there is some limitation to shutter speed at certain F/stops, although I can't seem to find that now... it was something to the effect that even with the override, if the F/stop value was not in the right range, the shutter would still be slower than what you put in. That sounds like what I'm experiencing, so perhaps more experimentation with the F/Stops will help this.. if anyone has any details on if there really is such a limitation and what the parameters are, that would be most helpful.

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