Increasing dynamic range at DVinfo.net

Noa Put · October 22nd, 2016, 04:07 AM

There is a trick I only sometimes use, as it doesn't always work, to increase the dynamic range of a camera, it involves a simple use of a mask in Edius (and I"m sure other NLE's have this option as well) and letting the camera run with 2 different exposures, in below case I exposed the background right and let the camera run for a while and then exposed correctly for the foreground which made the church in the back over expose, afterwards I cut out the window part of the shot I did with the correct exposed outside and layed it over the footage which was exposed for the inside part. This ofcouse only works if no-one walks in front of the window but in a few rare cases I have been able to apply this trick to increase the DR dramatically on a camera, the mask I applied is a bit rough in below example and could be finer with some more time but it's just to show what is possible. Anyone using similar tricks?

Mervyn Jack · October 22nd, 2016, 05:41 AM

Good job Noa. I used one of your mask ideas to remove myself from a shot in a church wedding last year.

Steven Shea · October 23rd, 2016, 05:02 PM

Yes, I've done similar things with skies and windows. Even with basic interviews, I'll often re-light in post to some extent, with power windows.

Chris Harding · October 24th, 2016, 07:28 PM

Hi Noa

I think you showed us something similar previously ...of course if you have a couple moving around against a badly backlit scenario you are essentially screwed as you would have to adjust the mask almost every frame which would be painstaking ! I had a rained out wedding a few weeks ago where I had to blow out the background to get a correct exposure of the couple (there were sadly no options to move the camera as the idiot celebrant crammed 50 people into a tiny gazebo!! I wonder if a partial mask might look better? so you just leave a bit of a halo around the couple's heads instead of over exposing the entire background ...If you had an issue like that, what would you do (apart from cry?)

Donald McPherson · October 24th, 2016, 11:50 PM

Magic Lantern for Canon DSLRs has a similar idea every second frame captured takes different exposure. There are tutorials and YouTube's that can explain far better than I ever could.

Chris Harding · October 25th, 2016, 03:08 AM

That sounds interesting? So the first frame would expose for the foreground and blow out the background and then the second frame would correctly expose the background making the foreground under-exposed ? You would then have 25 frames under and 25 frames over so when it plays back the dynamic range is wider as they balance each other out? Could be an interesting way of doing things! Have you actually tried it???

Donald McPherson · October 25th, 2016, 05:22 AM

Only tried once out of interest. But there are some good videos out there with good examples. I'll look for some and post.

Noa Put · October 25th, 2016, 05:51 AM

Quote:

Originally Posted by Chris Harding

I wonder if a partial mask might look better? so you just leave a bit of a halo around the couple's heads instead of over exposing the entire background

That wouldn't look good + it would take many hours to keyframe your mask for a one hour ceremony, what I showed only works well if you have no movement in the part you replace.

Donald McPherson · October 25th, 2016, 07:19 AM

Here is a good link explaining the process.

October 22nd, 2016, 04:07 AM	#1
Noa Put Inner Circle Join Date: Jun 2007 Location: Belgium Posts: 9,509	Increasing dynamic range There is a trick I only sometimes use, as it doesn't always work, to increase the dynamic range of a camera, it involves a simple use of a mask in Edius (and I"m sure other NLE's have this option as well) and letting the camera run with 2 different exposures, in below case I exposed the background right and let the camera run for a while and then exposed correctly for the foreground which made the church in the back over expose, afterwards I cut out the window part of the shot I did with the correct exposed outside and layed it over the footage which was exposed for the inside part. This ofcouse only works if no-one walks in front of the window but in a few rare cases I have been able to apply this trick to increase the DR dramatically on a camera, the mask I applied is a bit rough in below example and could be finer with some more time but it's just to show what is possible. Anyone using similar tricks? Vimeo

October 22nd, 2016, 05:41 AM	#2
Mervyn Jack Regular Crew Join Date: Mar 2014 Location: Shepparton, Vic, Australia Posts: 78	Re: Increasing dynamic range Good job Noa. I used one of your mask ideas to remove myself from a shot in a church wedding last year.

October 23rd, 2016, 05:02 PM	#3
Steven Shea Regular Crew Join Date: Dec 2013 Location: Vancouver, Canada Posts: 58	Re: Increasing dynamic range Yes, I've done similar things with skies and windows. Even with basic interviews, I'll often re-light in post to some extent, with power windows.

October 24th, 2016, 07:28 PM	#4
Chris Harding Inner Circle Join Date: Jul 2009 Location: Perth, Western Australia Posts: 8,441	Re: Increasing dynamic range Hi Noa I think you showed us something similar previously ...of course if you have a couple moving around against a badly backlit scenario you are essentially screwed as you would have to adjust the mask almost every frame which would be painstaking ! I had a rained out wedding a few weeks ago where I had to blow out the background to get a correct exposure of the couple (there were sadly no options to move the camera as the idiot celebrant crammed 50 people into a tiny gazebo!! I wonder if a partial mask might look better? so you just leave a bit of a halo around the couple's heads instead of over exposing the entire background ...If you had an issue like that, what would you do (apart from cry?)

October 24th, 2016, 11:50 PM	#5
Donald McPherson Major Player Join Date: Jun 2010 Location: Aberdeen Scotland Posts: 815	Re: Increasing dynamic range Magic Lantern for Canon DSLRs has a similar idea every second frame captured takes different exposure. There are tutorials and YouTube's that can explain far better than I ever could.

October 25th, 2016, 03:08 AM	#6
Chris Harding Inner Circle Join Date: Jul 2009 Location: Perth, Western Australia Posts: 8,441	Re: Increasing dynamic range That sounds interesting? So the first frame would expose for the foreground and blow out the background and then the second frame would correctly expose the background making the foreground under-exposed ? You would then have 25 frames under and 25 frames over so when it plays back the dynamic range is wider as they balance each other out? Could be an interesting way of doing things! Have you actually tried it???

October 25th, 2016, 05:22 AM	#7
Donald McPherson Major Player Join Date: Jun 2010 Location: Aberdeen Scotland Posts: 815	Re: Increasing dynamic range Only tried once out of interest. But there are some good videos out there with good examples. I'll look for some and post.

October 25th, 2016, 07:19 AM	#9
Donald McPherson Major Player Join Date: Jun 2010 Location: Aberdeen Scotland Posts: 815	Re: Increasing dynamic range Here is a good link explaining the process. YouTube (Short URL)

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