Author Topic: Shoot prep technical issue  (Read 1954 times)

Matty_UK

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Shoot prep technical issue
« on: June 18, 2018, 03:26:59 PM »
Hi, I was hoping to get an answer by this weekend (I'm doing a shoot) but in the Help forum, the moderator hasn't been active for two weeks... sorry if this isn't quite in the right forum, but I'm getting desperate now. I installed a new build of ML, thinking it would fix the issue, but it hasn't.

Please see the video for the issue. You can hear the lens (blades?) moving too: https://youtu.be/rgWn5GK-SSk

I've tried researching this issue over the past few months, but found nothing. So I'm hoping someone here can help.

I'm using a Canon 1100D. I had an older version of ML and had this exact same issue as I'm having now with the newest build. It affects about 30% of the shots I take. HELP! It's visible in live view and on the saved video (mov) file.

I'm not too camera savvy - I only want ML to achieve 180 shutter rule in movie mode. To achieve the 180 rule for 25fps I turn on 'expo. override' and change shutter to '1/50.00, 180°'. Expo Override in itself doesn't cause the issue at its default '1/33.33, 270°'. it's only after I manually change the shutter from 270° to 180°, the 'flickering' begins.

I'm currently shooting a year-long project, I started using 1/50, 180° so I can't change now...

It seems to only happen when there's high contrast in the frame. Or contrast changes i.e. filming back of their head and the turn round - their face causes this. Doesn't matter what lens I use either, although swapping them sometimes 'fixes' the issue.

I don't know if this is related, but on bright days I struggle to get video that isn't too washed out. Using a higher f stop from the ML menu does seem to do anything in live view?

Hope I've explained it well enough. Many thanks for any help!

Anyway here's the log data:

# Magic Lantern Nightly.2018May01.1100D105

Start          : 2018/06/17 08:20:57
Lens name      : EF-S18-55mm f/3.5-5.6 III
ISO            : 400
Shutter        : 1/50.000s
Aperture       : f/5.6
Focal length   : 20 mm
Focus distance : 1130 mm
White Balance  : 6500K, Magenta 0, Blue 0
Picture Style  : Neutral (0,0,0,0)
FPS            : 25.000
Bit Rate (CBR) : 1.0x

CSV data:
Time,ISO,Shutter,Aperture,Focal_Len,Focus_Dist
08:20:57,400,50,5.6,20,113

Levas

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Re: Shoot prep technical issue
« Reply #1 on: June 18, 2018, 05:32:15 PM »
Do you film in M(anual) mode on the mode dial, or are you using some auto setting like Av(aperture priority) or Tv(shutter time priority) ?

allemyr

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Re: Shoot prep technical issue
« Reply #2 on: June 18, 2018, 05:57:11 PM »
Why not skip using the ML expo override feature? And just set the camera to 1/50 in the Canon menu?

"But in the Help forum" what forum page is that?

Levas

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Re: Shoot prep technical issue
« Reply #3 on: June 18, 2018, 06:31:20 PM »
Searched for a picture of the 1100d and found out that it has a dedicated movie option on the mode dial, so it's not like on most other camera's.

Looking at the video on youtube I think the camera tries to do autoexposure. Is there a lock exposure option on the 1100d in video mode ?

allemyr

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Re: Shoot prep technical issue
« Reply #4 on: June 18, 2018, 06:53:39 PM »
Hi!

Check page 141 in the Canon 1100D manual!

http://gdlp01.c-wss.com/gds/0/0300004730/02/eosrt3-eos1100d-im2-c-en.pdf

Its autoexposure only in the movie mode! You could lock the auto exposure but not change it like you want i guess?

The older Canon 550D is better!

Didn't realize that 1100D was that of a cheap entry camera like it was 2011.

Now my 600D that from around the same year was twice as expensive feels like a pro camera but that is 7 years ago. Time flies!

Shit, I need to stop using this forum, tho I adore magic lantern!

Matty_UK

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Re: Shoot prep technical issue
« Reply #5 on: June 18, 2018, 11:00:17 PM »
Do you film in M(anual) mode on the mode dial, or are you using some auto setting like Av(aperture priority) or Tv(shutter time priority) ?

1100D has only a 'film camera' icon on the dial. There's not a lot of options within video mode and no auto/manual option to change in the settings.

Why not skip using the ML expo override feature? And just set the camera to 1/50 in the Canon menu?

"But in the Help forum" what forum page is that?

1100D won't let me change that using its default firmware! That's why I need ML.
Help forum - the General Help Q&A here: https://www.magiclantern.fm/forum/index.php?board=4.0

Searched for a picture of the 1100d and found out that it has a dedicated movie option on the mode dial, so it's not like on most other camera's.

Looking at the video on youtube I think the camera tries to do autoexposure. Is there a lock exposure option on the 1100d in video mode ?

Yeah, it's a bit rubbish the 1100D. 720p... no audio input either. Bit pathetic. There is an exposure lock option! (see next quote)

Hi!

Check page 141 in the Canon 1100D manual!

http://gdlp01.c-wss.com/gds/0/0300004730/02/eosrt3-eos1100d-im2-c-en.pdf

Its autoexposure only in the movie mode! You could lock the auto exposure but not change it like you want i guess?

The older Canon 550D is better!

Didn't realize that 1100D was that of a cheap entry camera like it was 2011.

Now my 600D that from around the same year was twice as expensive feels like a pro camera but that is 7 years ago. Time flies!

Shit, I need to stop using this forum, tho I adore magic lantern!

Ha! Thanks, that's quite helpful actually. When it's daylight I'll give it a go using the lock button. If that doesn't work I'll put it down to being an old budget camera.


Many thanks for all your help. And thanks moderator who put my topic live.

allemyr

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Re: Shoot prep technical issue
« Reply #6 on: June 19, 2018, 03:10:22 PM »
You are welcome! Thx for saying thx  ;)

Hope film/videomaking goes fine now!

Matty_UK

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Re: Shoot prep technical issue
« Reply #7 on: June 19, 2018, 07:41:51 PM »
:)

We had zero sunlight today so couldn't get the 'flicker' to trigger. 95% of the time it only happens when the sun is bright.

Will try tomorrow.

Matty_UK

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Re: Shoot prep technical issue
« Reply #8 on: June 20, 2018, 10:56:10 PM »
Again. No sunlight when I got home....

Kharak

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Re: Shoot prep technical issue
« Reply #9 on: June 20, 2018, 11:42:42 PM »
Are you sure it is not your Lens aperture pulsating?

I know that the canon 50 mm 1.8 With exposure overide and set to (some) non-standard fstops, like 2.2. would cause the aperture to pulsate.

Try disabling Expo. Overide. See if it helps.
once you go raw you never go back

allemyr

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Re: Shoot prep technical issue
« Reply #10 on: June 21, 2018, 08:08:05 AM »
Try disabling Expo. Overide. See if it helps.

"Why not skip using the ML expo override feature?" nice difference :)

"Its autoexposure only in the movie mode!" says the Canon 1100D manual.

The only thing that you can do when using the 1100D in the movie mode is to use a exposure lock, let the camera do the autoexposure and then lock it.
1100D is quite limited, so I understand that TS used the Expo override which on this camera doesn't work.

a1ex

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Re: Shoot prep technical issue
« Reply #11 on: June 21, 2018, 08:27:22 AM »
Exposure override is known to have some issues with this particular lens (EF-S18-55mm f/3.5-5.6 III) and a few others; unfortunately there's no known fix. This feature relies on some debug routines in Canon firmware, which are not very well understood.

Workaround: set the aperture manually, then unscrew the lens while recording.

I'm still looking into it, though not exactly with high priority.

allemyr

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Re: Shoot prep technical issue
« Reply #12 on: June 21, 2018, 08:40:53 AM »
Workaround: set the aperture manually, then unscrew the lens while recording.

Ok, so the solution would be to go into manual in photo mode, set aperture, unscrew lens, and switch to movie mode and then record?

Matty_UK

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Re: Shoot prep technical issue
« Reply #13 on: June 21, 2018, 09:57:33 PM »
Are you sure it is not your Lens aperture pulsating?

I know that the canon 50 mm 1.8 With exposure overide and set to (some) non-standard fstops, like 2.2. would cause the aperture to pulsate.

Try disabling Expo. Overide. See if it helps.

Not using non-standard fstops is interesting. That could have been an early workaround.

Disabling expo. override; it’s fine to do that, but I specifically need 1/50 shutter speed for 25fps. Cannot achieve that without expo. override on 1100D sadly.

"Why not skip using the ML expo override feature?" nice difference :)

"Its autoexposure only in the movie mode!" says the Canon 1100D manual.

The only thing that you can do when using the 1100D in the movie mode is to use a exposure lock, let the camera do the autoexposure and then lock it.
1100D is quite limited, so I understand that TS used the Expo override which on this camera doesn't work.

100% correct. And many thanks again. I finally got to try the lock feature today and it WORKED! I also bought a hama nd2-400 (mainly for my 50mm) for bright days too. I took a couple of shots in the garden, wow the difference is shocking! I actually feel like I’ve learned a lot for doing this.

Exposure override is known to have some issues with this particular lens (EF-S18-55mm f/3.5-5.6 III) and a few others; unfortunately there's no known fix. This feature relies on some debug routines in Canon firmware, which are not very well understood.

Workaround: set the aperture manually, then unscrew the lens while recording.

I'm still looking into it, though not exactly with high priority.

That’s good to know. And that workaround will be an excellent backup if all else fails. Thank you for your reply.

Ok, so the solution would be to go into manual in photo mode, set aperture, unscrew lens, and switch to movie mode and then record?

I’ll have to try this.

Matty_UK

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Re: Shoot prep technical issue
« Reply #14 on: August 12, 2018, 01:40:26 PM »
Thought I'd pop back to say thanks.

Filming went really well, the lock feature worked perfectly. We finished in record time :D