Hi. I accidentally left the XC15 in aperture priority F8 and autofocus. The clip has 2 parts. The first 20 seconds (no audio) was shot nearly directly into the sun. A couple of steps left and direct intense sun reflection appears on the water.

The autofocus swings wildly. The exposure is pulsing up and down.

The last 12 seconds (seems normal) is shot facing the opposite direction, though with the same settings.

Other points are...

1. The audio is bad in part 1 because one of the transmitters was accidentally left on 12V.
2. Both are shot in log with a Canon 1D LUT applied
3. No ND filter into the sun

I'm trying to understand this camcorder. Is the intense light too much for it? Could the audio voltage issue have thrown the exposure and focus out of whack?

Thanks much for any thoughts on this.

https://youtu.be/j4fakI_v1Jg

Just the mega bright reflections in the sensor auto area that are identified as the overall brightness changing, and anything auto would be confused. Autofocus and auto exposure is historically known for these issues, although in fairness they have been getting better. I assume you weren’t looking at the image when you were shooting?

Every camera responds differently. One of mine jitters the brightness, a sort of wobble that looks odd when it’s adjusting slightly slower than the reflections and can’t keep up. It’s old and over the years I just know when it will play up. Sunlight on waves is where it’s worst. Those little pinprick hotspots are probably your danger area and it will be fine on everything else. I’m old, so autofocus has never worked for me. Always unreliable.

Plus, there's some camera movement.

Edit: Yep, stepping through the downloaded video, I'd say it's camera movements catching flare and specular reflection, off the water, from the sunlight coming through trees on the right, just out of frame.

This is so helpful, thanks much! So in hindsight, manual exposure and focus.

It is log and highs were not terribly blown out. Would ND have helped the first scene with the high contrast?

Yes definitely on the shaking. How does that pick up flare? Also, are you saying the movement also magnifies the specular reflection? (which I just looked up :)

The pulsing is caused by auto exposure, shooting in manual would solve that issue.

ND filter wouldn't fix this or give you more dynamic range. ND filters are still useful because in bright conditions there are only 3 ways to reduce the light. The first is the aperture but usually its not possible to close the aperture enough and other times you might want the aperture to be wide open for a shallow dof. The second way is the shutter speed. Ideally the shutter speed should be no more than twice the frame rate. If it's set too high it can look odd. So that's why ND filters are used to control the exposure so the aperture and shutter can be left at their optimal settings.

Shooting outdoors is a specialty unto itself.

Still think it's primarily flare/glare 'haze' coming from strong specular, and diffuse, reflections off the water on the far right side. The left side of the frame is far less affected. Actually, stepping through the video again, I'm less inclined to think it's camera movement, as there are also strong flashes when the camera is static. Could easily be due to the sunlight breaking through patchy cloud passing over though. There's also what could be a flare spot (light purple) on the tree, just up-right from center, unless it's dust or a dried water spot, which would be more conspicuous at higher aperture.

We’re all right. Those reflections of the sun are at almost sun intensity, so when they are in the cameras auto exposure zone they Indicate the exposure is too high and it closes the aperture, or sensitivity depending on setting. As the water moves, these triggers the. Vanish and the camera compensates. I have a small handicam that is terrible in its control. Far too quick and sharp and in some circumstances it wobbles or flickers. Fast moving clouds ramp the brightness up and down very noticeably. Another camera is very slow to compensate and much better. Churches cause me problems with windows with stained glass. As clouds and sun play outside, the changes inside set off the small camera, but annoyingly it’s manual control is terrible.

This phenomenon is quite normal for some cameras, and you work around them.

Still think it's primarily flare/glare 'haze' coming from strong specular, and diffuse, reflections off the water on the far right side.

You are absolutely correct. The issue seen here has nothing to do with exposure fluctuation.

If you cover up the right hand side of the frame, the exposure level of the entire image changes. Something is clearly influencing the camera's exposure. Traditonal point sources that cause flaring tend to only influence parts of the whole frame. This appears to be a frame wide artefact, hence my belief it's electronic in nature, rather than a physical iris movement. Should be easy to replicate in the studio with a grey card and a torch. Sorry Doug, we will have to differ in our opinions.

The left side of the image is far less effected though. Examining the histogram behavior (in Resolve) you can clearly see that the luminance 'pulsing' is much stronger in the cropped right third of the image compared to the left, and that the pulses are irregular. Also if it were due to in-camera auto-exposure fluctuation you would expect to see marked fluctuation in the height (intensity) of the specular peak (at 255, when examined at 'Full' data level), and you don't - it stays pretty constant.

Bryan, you are exactly correct again. This is not an auto-exposure problem. If I could download the original file and run it through my waveform monitor it would be obvious.

Needless to say, nigh-on impossible to fix, successfully, in post.

I'm late to the discussion, but wanted to say that my first thoughts were that the wind was moving leaves/branches of a nearby tree and this was causing the rapidly blocking and then un-blocking of sunlight directly hitting the lens.

You may find that the de-flicker filter from RE:Vision Effects fixes it, per the example at 28 seconds on the demo video. Might as well give it a try.

DEFlicker Overview Reel - YouTube

Andrew

I tried it with a VirtualDub 'deflicker' plugin, without success:

https://www.compression.ru/video/deflicker/index_en.html

Could also try their 'Smart Brightness and Contrast' plugin:

https://www.compression.ru/video/smart_contrast/index_en.html

I had a degree of success with it for smoothing out mild variances in brightness in some dive videos, but I doubt it would really help in this case - for one thing, to work well the brightness needs to fairly uniform across the frame.

Resolve (which I know the OP uses) has a 'Dehaze' FX filter, but it is only available (without a bold logo watermark( in the Studio version. 'Dehaze' filters can work quite well for treating/dampening static flare haze. The problem in this case is compounded by the fact that these irregular haze bursts are appearing over a complex background.

There again, the OP hasn't asked for a fix.

I tried the dehaze filter but no benefit. The built-in deflicker effect seems to help quite a bit, best with the default settings - though not enough to make it usable.

I understand ND would not help. Also that my thoughts about the transmitter voltage made no sense at all :)

Also if it were due to in-camera auto-exposure fluctuation you would expect to see marked fluctuation in the height (intensity) of the specular peak (at 255, when examined at 'Full' data level), and you don't - it stays pretty constant.

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

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

I see the right being more affected. Shadows on the left, equally dark to right are less over exposed during pulses. How is that? Maybe (as I think you've been saying) the pulsing specular reflection (wind moving trees and gravity moving water) is the light source the sensor is responding to. Maybe we're blinded to the effect by looking away from the annoying intense glare (which there was). The poor camera sensor had to look.

Are such pulses there, but we can't make them out bare-eyed? The inverse square law throws much less light on the opposite bank (speculating). Maybe a good way to damage a sensor :-/

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.

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’.

Just to add:

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.

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.


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.


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


Such is the nature of lens flare.


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.


Maybe a good way to damage a sensor :-/

Not really.

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

One thought - you did have the lens hood fitted ?

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?

https://youtu.be/MsqN94fnVx8

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.

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.

Duplicate post

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!

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.

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!