Magic Lantern Sunrise at DVinfo.net

Tariq Peter · September 4th, 2012, 05:20 PM

Hi,

I am trying to shoot a sunrise time lapse and am really struggling with flicker. I am using the latest version of ML and tried using AV mode but that had flicker I switched to all manual with Bump Remap and now I am getting random images which are really bright. My settings are

Lens is set to 2.8 manual mode, 16-35mm Canon L Lens
Camera set to M mode
Intervalometer is set to 2 seconds
Bulb/Focus set to sunrise
Max Ramp speed set to 0.050

Expo menu set to ISO 1600
Shutter 1/25

Photo Album - Imgur every 5 - 8 frames a picture is brighter than the rest. I have uploaded 7 images here. The first is bright and so is the 5th

Any reason for this?

Jon Fairhurst · September 4th, 2012, 07:12 PM

You say the lens is at f/2.8. You might double check this. The one reason I've experienced flicker is when the lens is stopped down. Since the aperture opens and closes for each photo, the aperture changes slightly from image to image. The solution I use (with an intervalometer and not with ML) is to set the aperture, push the DOF Preview button, and partially untwist the lens. That guarantees that the aperture is fixed.

Aside from that, I don't know of any reason for flicker, aside from a possible ML bug. It could be a multitasking thing - it always works perfectly, except when it doesn't. :)

Jordan Hooper · September 5th, 2012, 11:22 AM

Have a look at the user guide again to see if the suggestions help. For example:

Quote:

Maximum ramping speed: this parameter is used for computing the optimal smoothness factor. A lower value will reduce flicker, but if the value is twice as low as the real rate of brightness change, ML will lose the ability to ramp correctly. For example, if you set a maximum ramping speed of 0.1 EV / shot, and the scene requires a ramping of 0.2 EV / shot, ML will start flickering heavily.

The user guide is here:
userguide [Magic Lantern wiki]

About 2/3rds of the way down the page is advice for controlling flicker in the QuickStart section in points 4 and 5.

Just reading the part I quoted and looking at your settings it might be that your ramping speed is too low. I haven't experimented with ramping yet so sorry if I'm sending you down the wrong path.

Let us know what you discover. Info is tough to find on some of the more advanced functions of ML and it will help others if you tell us what you figure out.

September 4th, 2012, 05:20 PM	#1
Tariq Peter Major Player Join Date: Jun 2007 Location: Manchester England Posts: 435	Magic Lantern Sunrise Hi, I am trying to shoot a sunrise time lapse and am really struggling with flicker. I am using the latest version of ML and tried using AV mode but that had flicker I switched to all manual with Bump Remap and now I am getting random images which are really bright. My settings are Lens is set to 2.8 manual mode, 16-35mm Canon L Lens Camera set to M mode Intervalometer is set to 2 seconds Bulb/Focus set to sunrise Max Ramp speed set to 0.050 Expo menu set to ISO 1600 Shutter 1/25 Photo Album - Imgur every 5 - 8 frames a picture is brighter than the rest. I have uploaded 7 images here. The first is bright and so is the 5th Any reason for this?

September 4th, 2012, 07:12 PM	#2
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Re: Magic Lantern Sunrise You say the lens is at f/2.8. You might double check this. The one reason I've experienced flicker is when the lens is stopped down. Since the aperture opens and closes for each photo, the aperture changes slightly from image to image. The solution I use (with an intervalometer and not with ML) is to set the aperture, push the DOF Preview button, and partially untwist the lens. That guarantees that the aperture is fixed. Aside from that, I don't know of any reason for flicker, aside from a possible ML bug. It could be a multitasking thing - it always works perfectly, except when it doesn't. :) __________________ Jon Fairhurst