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Using Magic Lantern => General Help Q&A => Topic started by: Alex_w315 on December 09, 2018, 08:28:00 PM

Title: Canon 1100d - Light / Dark Flashing in expo override mode
Post by: Alex_w315 on December 09, 2018, 08:28:00 PM
Hi,

Hoping someone can help me, sorry if this is a noob question/problem. Just downloaded ML for some shooting with my rather old Canon 1100D and having some lighting/ISO issues when filming with EXPO override on. I don't have any other settings switched on - HDR specifically as i know this can happen with this setting.

To be more precise, i've uploaded the footage here: https://youtu.be/6r5zevGymLo

I don't have my hands on any buttons, but the camera sounds like it's trying to autofocus but the focus doesn't change, just flashes between what looks like a low ISO setting and then high.. even though HDR setting is OFF... strange.

Take a look and let me know if you can help.

Thanks,
Alex

Title: Re: Canon 1100d - Light / Dark Flashing in expo override mode
Post by: Walter Schulz on December 10, 2018, 11:50:05 AM
Does this happen in a truely static scene, too? No incandescent lighting testing this, please (AC driven tungsten bulb, pulsed LED, fluorescent bulb, ...).
Title: Re: Canon 1100d - Light / Dark Flashing in expo override mode
Post by: Alex_w315 on December 10, 2018, 02:22:08 PM
Hi,

Thanks for your reply. There are no other lighting elements used in the footage uploaded. The issue seems to happen randomly when adjusting the camera position/zoom/focus, going between lighter and darker shots, then once it starts it doesn't stop. I'm sorry I can't give you any more info other than it stops when I turn EXPO override off...

Thanks,
Alex
Title: Re: Canon 1100d - Light / Dark Flashing in expo override mode
Post by: Walter Schulz on December 10, 2018, 02:47:59 PM
For debugging reasons I asked if anything changes in a scene without any movement (if possible) and no variations in lighting (if possible).
Title: Re: Canon 1100d - Light / Dark Flashing in expo override mode
Post by: Alex_w315 on December 12, 2018, 08:47:48 AM
Hi,

Thanks for clarifying. I can confirm in a completely static scene with no lighting variations the problem does not occur..
Title: Re: Canon 1100d - Light / Dark Flashing in expo override mode
Post by: Walter Schulz on December 12, 2018, 09:14:18 AM
Thanks for your testing!
I will try to reproduce your issue. Do you know cam settings (esp.: Metering mode, metering area (if applicable)) used for the shot showing exposure flicker?
Not absolutely necessary because I think I have an idea what has gone wrong and why.

EDIT: Reproducing is more difficult than I thought. 1100D is among the cameras where Expo. Override is needed to control  some basic settings (bypassing Canon's restrictions). None of my cams is restricted in this way.
Someone with 1100D (if possible) or 500D/50D around able to jump in?

@Alex_w315: Just a wild guess ... ALO is off and HTP, too?
Title: Re: Canon 1100d - Light / Dark Flashing in expo override mode
Post by: Alex_w315 on December 23, 2018, 10:14:47 AM
Hi,

Just an update on this as i didn't want your help to go to waste. After a fair amount of time spent researching, tinkering and testing (all previous recommendation followed); I've come to the conclusion the the problem lies in the aperture override setting - when I had the aperture set to anything over say f.5-6 (in open-air daylight - low-lying, winter sun and no cloud coverage) the problem would persist. Bringing the aperture to something like f.3-4 would mean the problem went away.

I only really got ML so that i could change these setting to alter the shot set up (as you pointed out in a  previous post, the canon 1100d is pretty much full auto in video and only has a poxy 'exposure' adjustment) so the fact that overriding these settings caused the problem is a bit annoying. I was able to utilise other ML features that made it altogether easier to get the results i wanted.

I'm not sure if the problem can be fixed, or if this information is of any help but, for the time being, i will continue using ML for it's other helpful features - just not to override the aperture.

Thanks and Merry Christmas. I hope Santa brings me a new camera ;)