Unexpected natural light pulsing

[Pete Cofrancesco]

As others have correctly identified pulsing effect is from the sun reflection up from the water hitting your lens causing flaring. Due to either the clouds, trees moving, or some other variable this is causing the glare to fluctuate.

In my experience the ability to properly view what your filming under direct sunlight is essential, allowing you identify problems like this when you're filming not after you get home.

What would prevent this might be as simple as adjusting you camera angle. Like I said before filming outdoors is specialized situation.

[Paul R Johnson]

I guess I have to take it on the chin, but it does occur to me that is a fairly common compositional scene, and if point sources do that so badly, it must be a really, really terrible lens. The lenses I use for ground to air parachuting don’t do a level dip when the sun bombs through a frame, and living by the sea with waves and water and trees and sun has never done it to me on cheap or expensive lenses. You can lose contrast, you can get visible flaring, and all sorts of the Bokeh style artefacts. It makes me wonder how many everyday setups this camera can cope with if it’s so prone to producing these artefacts. I usually assess things by changes in contrast being lens produced and changes in brightness coming from somewhere else.

I do realise I’m a lone voice and often wrong in many, many areas, but something in that clip just isn't ‘normal’.

[Bryan Worsley]

Just to add:

Originally Posted by Nick Mirro

The built-in deflicker effect seems to help quite a bit, best with the default settings - though not enough to make it usable.

With the VirtualDub MSU Anti-Flicker filter there was a very slight dampening in the amplitude of the pulses when the filtered and un-filtered clips were examined in Resolve on the scopes, but not to the naked eye.

Originally Posted by Nick Mirro

If I display the qualifier, the points of intense reflection in the parade dance up and down.

I don't see that. Applying a luminance qualifier (key) to the 'super-whites' (941-1024 range in 10bit, 236-255 in 8bit) I don't see any marked fluctuations in the intensity and/or 'spread' of the key mask, which you would expect with changes in in-camera exposure. Of course there is movement of the specular highlights on the water, because the water is moving.

What I see are essentially 'gamma' pulses, consistent with flare haze.

Originally Posted by Nick Mirro

Wouldn't this be gone if I shot in manual? That would lock the aperture and gain.

I don't think so, but you could always test that for yourself under similar conditions.

Originally Posted by Nick Mirro

Are such pulses there, but we can't make them out bare-eyed?

Such is the nature of lens flare.

Originally Posted by Nick Mirro

The inverse square law throws much less light on the opposite bank (speculating).

More complicated than that, as the phenomenon has to do with the way the peripheral light reflected off the water on the right is hitting and being scattered by the lens.

Originally Posted by Nick Mirro

Maybe a good way to damage a sensor :-/

Not really.

Originally Posted by Paul R Johnson

....something in that clip just isn't ‘normal’.

One thought - you did have the lens hood fitted ?

[Nick Mirro]

Thanks Bryan. This thread is really encouraging after that clip left me feeling painfully amateur.

The standard XC15 lens hood was fitted. I should restate, the light was intense, such that If I aligned to see the sun's actual reflection in the water, I would be blinded, so I shifted to the right. So, the light source was as close to the camera frame as possible without being in it.

It was still so intense that I could not see the Ninja Inferno image well. Just enough to compose it, but certainly not enough to see the focus swinging wildly or the light pulsing.

I'm probably confused about the specular highlights. Still pretty new at DR and non-consumer editing software. I'm sure once I have the scopes down pat it will make sense.

I now understand that the effect is happening in the lens barrel. I didn't know that glare originated in the lens, probably since I never gave it much thought. Seems obvious now.

Is this youtube example of pulsing the same effect?

YouTube (Short URL)

[Bryan Worsley]

Well yes, that's how lens flare can look when pointing directly at a very bright light source. It's an animation though. In your video it manifests as a diffuse glare 'haze', simply because of the way patches of sunlight breaking through from behind the camera are being reflected off the water. That's the only reason for the 'pulsing', as we've called it.

Originally Posted by Nick Mirro

I should restate, the light was intense, such that If I aligned to see the sun's actual reflection in the water, I would be blinded, so I shifted to the right. So, the light source was as close to the camera frame as possible without being in it.

So, evidently the right conditions for creating lens flare. Just something to be aware of and to avoid in the future.

[Bryan Worsley]

Duplicate post

[Nick Mirro]

Well marvelous! Another of countless hurdles cleared. The science and complexity of videography is intoxicating, whether or not one can actually create anything of value. :)

Thanks so much for taking time here. Back down to the river!

[Bryan Worsley]

I think you are being a bit hard on yourself. You've got a great camera there. It's more a question of discovering for yourself what works and what doesn't in different scenarios.......and when something doesn't work as you expected/hoped, not jumping to the conclusion that something must be wrong with the camera.

[Nick Mirro]

I agree the XC15 is great and see this as part of the learning curve. Am a gear junkie and have always loved Canon. The XC complements the XF400 nicely. Thanks again, this thread has been a huge help and encouragement!