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Re: Wave-Freefly Hi Speed Camera

Re: Wave-Freefly Hi Speed Camera


Brian Heller
 

To add to Bob Kertesz’s cogent post, the phenomenon whereby the color of objects that appear to the eye to be the same, but are rendered differently to different sensors or under different lighting, is called metamerism, or more precisely: illuminant metameric failure.

There’s plenty of information on the subject on line and also in the CML archives.

Brian Heller
IA 600 DP


On Apr 2, 2021, at 2:08 PM, Bob Kertesz <bob@...> wrote:



Would shooting through IRND Filters help to even out the blacks reaching the sensor?

Cynthia Webster DP


Yes, if there's actual IR present. Even when subtle (and depending on the camera/lens/sensor), the changed blacks are the first thing I notice when IR is present, as they usually tend to go a brownish/reddish color on camera.

But it also depends on the material doing the reflecting. I once shot a promo with a four person Mariachi band all wearing tuxedos. All the tuxes looked black to the naked eye, but depending on the material used, they went different colors on camera from subtle browns to subtle greens. The only one that remained black was the one that seemed to be made with cotton. 100% cotton seems to absorb the IR and not reflect it back into the lens.

It has been my experience that a well used all cotton flag shoved in front of the camera can often be used as a 'standard', since unless the IR is wildly out of control (shooting outside in bright sunlight with a ton of non-IR coated NDs), it will remain black in the presence of moderate IR. I used to use that trick to answer the question of "Why are the blacks different colors? What's wrong with your camera?" If the flag stayed black, the answer was "Nothing at all."

-Bob

Bob Kertesz
BlueScreen LLC
Hollywood, California

Mostly Retired Engineer, Video Controller, and Live Compositor Extraordinaire.

High quality images for almost five decades - whether you've wanted them or not.©

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