Author Topic: Motion Detection lightning shots  (Read 13071 times)

Rhodry

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Motion Detection lightning shots
« on: April 07, 2013, 08:25:38 AM »
Hi All

I'm new to the whole ML and was wondering if I could get a little help with the set up for night time motion detection for lightning.
I have a 60 D and normally have it set to trigger expo change and trigger level 3. My ISO is normally around 100 and F stop 10ish.
I was out last night trying to photograph lightning in Canberra and it would not trigger the camera, sometimes due to the rain I have to shoot from inside the car with the window down.
Do I have the correct settings and is there any advice I could get.
Thanks in advance
Jamie

Audionut

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Re: Motion Detection lightning shots
« Reply #1 on: April 07, 2013, 09:13:29 AM »
You'll be doing well to capture lightning with motion detect.  By the time the code reads the exposure change and triggers the shutter (and your camera shutter lag), the lightning will probably be finished.

I prefer to set my exposure for 30 seconds and have the intervalometer keep firing off shots.

30 second exposures are easy on the shutter, ensure you almost always get every lightning strike, and you can blend them in PS.

This was 9 shots out of 23 iirc.  Wasn't a very active storm front.

Jimbo

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Re: Motion Detection lightning shots
« Reply #2 on: May 07, 2013, 12:02:58 PM »
Thanks Audionut, that is interesting.  You say your 30 sec exposures "ensure you almost always get every lightning strike".    Do you have Canon's 'Long Exposure Noise Reduction' switched on or off?  I tend to leave this on as otherwise the noise is horrible - but then I lose 50% of my time as the software does its thing.  If you have it switched off - what do you use in its place?

ps Nice photo!

3pointedit

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Re: Motion Detection lightning shots
« Reply #3 on: May 07, 2013, 02:38:28 PM »
Also how do you set exposure for lightning with long exposure? Surely it is too easy to over expose?
550D on ML-roids

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Re: Motion Detection lightning shots
« Reply #4 on: May 07, 2013, 04:13:24 PM »
I caught lightning with motion detect. Something like ISO 5k, shutter 1/700 or more. It was pretty difficult though, only 1 photo out of many triggered just by the flash. Intervalometer and long exposures might be a better trick. Seems like it could get multiple strikes at once where motion detect will not.

Audionut

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Re: Motion Detection lightning shots
« Reply #5 on: May 07, 2013, 11:58:32 PM »
I have all Canon image adjustments turned off, long exposure noise reduction, high ISO noise reduction etc etc, and fix in post.

Long exposure noise reduction is dark frame subtraction
https://www.google.com.au/search?safe=off&client=firefox-a&hs=6mB&rls=org.mozilla:en-US:official&q=dark+frame+subtraction&spell=1&sa=X&ei=sXWJUePqJ4KEiAeE1YCAAQ&ved=0CC8QvwUoAA&biw=1920&bih=1001

Same thing, one is done in camera and means you miss half your shots, the other is done in post and means you capture as much as possible.

With camera on tripod you want lowest possible true ISO for least noise and longer shutter speeds (so your not replacing the shutter every other month)

You now have 2 exposures to deal with.  1 for the lightning and 1 for the ambient.  Aperture will control how bright your lightning (think of it as a speedlight) exposure is (how bright each strike is), and shutter will control how bright your ambient (everything else) is.

f/8.0 or so should be a good start for the lightning.  Try and capture some and check it's exposure.  It's pretty easy to dial back the blow-out on lightning in post, so don't worry if it's getting blown out heaps.  And if you are capturing ambient surrounding, you want to stay under your cameras 'diffraction limited aperture'.

Now take a test exposure for ambient.  Try 30 secs.  If the ambient is to bright use a shorter shutter speed.

Enable intervalometer in ML, hit start, have coffee and enjoy the show.

Seems like it could get multiple strikes at once where motion detect will not.

You'll get as many strikes as you can.  If it's an active storm front, you could end up with 5 or more strikes in one frame without any post blending.

noisyboy

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Re: Motion Detection lightning shots
« Reply #6 on: May 08, 2013, 12:44:42 AM »