Magic Lantern Forum

Using Magic Lantern => Tutorials and Creative Uses => Topic started by: chilimac02 on June 19, 2017, 03:01:01 PM

Title: Ideas for Correcting Contrast in Live Event Camera Use?
Post by: chilimac02 on June 19, 2017, 03:01:01 PM
I've been using my SL1 as a 2nd camera in a live event setting. Basically I boot ML, disable the display on the output and send signal via HDMI. Its a great and cheap live camera except for one issue. The highlights are way overblown. I've attached an image from the SL1 (its the ugly one) and then another from my xh-a1 camera. These are taken from a live stream which has been further compressed so the issue is magnified.

I would love suggestions for correcting the overblown highlights in a live-event setting like this. If there's already a thread please feel free to redirect me.

image from the SL1

(https://thumb.ibb.co/nz15DQ/Screenshot_2017_06_19_07_58_52.png) (https://ibb.co/nz15DQ)

bb code image (https://imgbb.com/)


Image from the xh-a1

(https://thumb.ibb.co/g6dtYQ/Screenshot_2017_06_19_07_59_13.png) (https://ibb.co/g6dtYQ)


I have already tried using color correction in my video swither but had no luck. Perhaps that's because of my lack of skills... Either way here was an attempt at correct the problem on the switcher, but it seemed to not really help...
SL1 modified in-switcher

(https://thumb.ibb.co/m94NSk/Screenshot_2017_06_19_08_03_24.png) (https://ibb.co/m94NSk)

image hosting website free (https://imgbb.com/)


xh-a1 untouched in switcher

(https://thumb.ibb.co/eYYtYQ/Screenshot_2017_06_19_08_03_37.png) (https://ibb.co/eYYtYQ)


thanks for taking the time to read this, and possibly help!
Title: Re: Ideas for Correcting Contrast in Live Event Camera Use?
Post by: a1ex on June 21, 2017, 01:19:24 AM
Quote from: chilimac02 on June 19, 2017, 03:01:01 PM
I would love suggestions for correcting the overblown highlights

Does it help if you reduce saturation in the picture style?

Do you have a CR2 image from the same scene? (just curious to see how various raw processors handle this case)

If you want to use Canon's color science (since you use HDMI out, you have to), having a CR2 of the tricky scene means you'll be able to experiment with Canon's raw processing software (DPP) and see what parameters will render it properly.

Quote
in a live-event setting like this.

I'm not sure what this implies. Should the adjustment be done automatically, in real-time? Should the saturation go back to the initial level once the highly saturated colors disappear from the scene? If yes, some script that looks at RGB zebras and adjusts saturation (maybe also exposure and white balance) might help, but a general solution is probably difficult (at least for my limited knowledge).
Title: Re: Ideas for Correcting Contrast in Live Event Camera Use?
Post by: chilimac02 on June 22, 2017, 02:02:24 PM
Thanks for the response.

I tried the idea of playing with the saturation and still wasn't able to get things quite right. I'll keep working on it and let you know...