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Using Magic Lantern => General Help Q&A => Topic started by: hd1roam on August 07, 2012, 03:43:57 PM

Title: Motion Detect Question - Lightning
Post by: hd1roam on August 07, 2012, 03:43:57 PM
I tried 'Motion Detect' to capture some lightning, medium dark skies during daylight hours - 15:00, with no luck. T2i ML ver 2.3.
Tried multiple settings and had no triggers except by my hand in front of the lens. Even threw stones out in front of lens, no result.

Any setting advice you all can offer.
Also please help me understand the trigger levels. Example; is it true the lower the number the easier it will trigger, as in more sensitive?
I could not find this in documentation. It could also be interpreted that a higher number is more sensitive so this understanding is needed.

Thanks
Dave
Title: Re: Motion Detect Question - Lightning
Post by: Malcolm Debono on August 07, 2012, 03:53:37 PM
Since lightning doesn't cause too much exposure difference (especially during daytime) you should use frame difference. Keep the level low, since it increases the sensitivity (i.e. a small change in scene triggers the shutter). You need to experiment with the level until the lightning triggers the shutter.

After activating the motion detection feature with frame difference, you'll see a box at the centre of the live view screen. Only changes within this area are taken into account, so make sure that the lightning occurs within this area.
Title: Re: Motion Detect Question - Lightning
Post by: hd1roam on August 07, 2012, 04:10:13 PM
Thanks Malcolm.
I had set with Frame Diff and level 3. ISO 100, AF=off and IS was still on maybe that should be switched off too.
I did not know about the box; on my screen I see two actually three; largest is less than one third of the screen wide, a smaller box more bold inside that, and a very tiny one inside the bold. ??
Is the largest box the trigger area?
Is there anyway to resize the box?

I guess maybe if the lightning is outside the box it probably is not grand enough to capture anyway. Yesterdays storm was pretty mild.
Title: Re: Motion Detect Question - Lightning
Post by: vk2him on August 13, 2012, 05:36:05 AM
I've been able to capture lightning reliably during the day using ML using both exposure and frame difference.

https://www.dropbox.com/s/8xik2f3i7l4214x/Lightning.jpg (https://www.dropbox.com/s/8xik2f3i7l4214x/Lightning.jpg)

The above was taken using exposure difference with a setting of 6

https://www.dropbox.com/s/kz3t0y93nlkraqw/gerroa2.jpg (https://www.dropbox.com/s/kz3t0y93nlkraqw/gerroa2.jpg)

The above was using frame difference.

Its trial and error, try setting up inside by pointing at your TV in the daylight - this is a good test for exposure ..

Good luck
Title: Re: Motion Detect Question - Lightning
Post by: StambaOS on September 08, 2012, 01:47:14 AM
When I turned on motion detection on mine 550D I got (picture was taken outside) very slow shutter speed - few seconds, and picture was white (because it was late afternoon). I shoot in Aperture mode and without live view everything was ok. Any idea?