Shimmering Closeup Footage
 

I was shooting out in a rural area today and when I looked at the footage this evening I noticed something I haven't seen before--a shimmering, almost like a visable heat wave--it almost looks like an effect as if it was shot in the Sahara or something! When I was zoomed into an object, for example I zoomed into some daisys and stopped, then just shot about 10 seconds of the daisys, they looked and look on the television very nice, but there's this shimmering, I don't know what else to call it, not a flickering like interlace flicker, not at all. When I shot at a midpoint between closeup and far away, it wasn't there at all. This happened later on when I was shooting a scene, when I came in close to the object.

Has anyone had this happen? Could shooting on a hot humid day cause this?

Not sure what this might be. What settings were you using...aperture, shutter, frame rate, wide or narrow, any custom presets? Any possibility of posting a short clip showing this?

Was optical image stabalising on whilst on a tripod ? I experienced a similar thing when using the 1.6x extender an 20x zoom, but I would have described the effect as vertical bouncing ....

Without seeing it, I'm guessing it's exactly what you said it was--heat rising. I don't where you are, but here in Miami you'll see it everyday when you shoot during the summer months (we have six of those down here), using the telephoto.

Jay

Jay,
I composed that very message twice and abandoned it both times. I thought Lucinda would tell me I was a moron, to which I would have replied, "un-uh, I'm more off than I am on".

Wow!...could it really be?! It's been humid here and that as you know makes everything really hot. It really looks like heat rising. It looks like a very cool effect. I just wasn't sure if the lens problem I've been having could have caused it. By the way, a new XL2 is on the way to me today! and Brian at ZotzDigital has checked it over and it's fine! let's hope. The shimmering also looks like a mirage...on the road, that's the sort of shimmering I'm talking about. What is vertical bouncing? and why would the image stabilizer cause that?

So, do you really think the cam could record the heat rising?!

I'm impressed. Have others experienced this?

As for moron Pat, you're far far from it!!

I feel shy about asking anything for fear seeming like a doo doo.

Lucinda,

Don't tell your camera manufacturer or NLE company that you recorded that...normally they make you pay extra for that.

My guess is that you actually recorded optical distortion from heat. At relatively close ranges, our binocular vision will 'edit out' this effect so that our brain records a relatively stable image. When we are looking farther down-range where we are using monocular vision or if the distortion is pronounced enough, we see the distortion. Of course the camera is always seeing the imagery as monocular vision (Except when using this lens at the bottom of this page, or like it).

A trick I learned of on another forum for getting 'heat waves' on command is to shoot over the hood of your car, keeping it just out of the shot. Of course, the car's engine needs to be hot. I haven't personally tried this out but it came from a news photog site so take it FWIW. Perhaps Stephanie Wilson will see this thread and chime in since that is her background.

-gb-

Hello,

A wild guess... were you using any ND filtering??

Hi All,

Pat, what do you mean?

Don't tell your camera manufacturer or NLE company that you recorded that...normally they make you pay extra for that.

Of course, you're kidding, right?

And Anthony, I don't remember if I used the ND filter for those clips. I know I used them later on during that same shoot. How would that affect the shimmer?

By the way, I used, just for the heck of it, a lower shutter speed and the ND filter to get a clip of large cumulus clouds and it looked really good. Normally, I'm shooting outside during the day at a 60th of a second, but I just wanted to try and see what would happen. That's not when I got the shimmering effect tho....I got that only when I came in close to the dandelions and the barn...the truck was a ways away. That couldn't have caused the shimmering.

Pat, do you think I can use this footage? I do like it.

Lucinda

Hello,

If you are using the ND filters in bright sunlight, they can give you optical effects that aren't expected... Ghosting, Blurring, and shimmering....

Heat effect is real, but you can see that with the naked eye as well, so you should have noticed it... but it may have been concentrating on other aspects within your frame.

That's why I mentioned it :-)

Anthony, I've never had ND filters affect anything but the overall light level reaching the sensors and thus the white balance. That's why they are called Neutral Density Filters, so they don't inject anything like ghosting, blurring, or shimmering. I'd bet if you had that happen when you installed an ND filter, it was a smudge on the filter.

Lucinda, yes I was making an obviously poor jest. And concerning whether or not the footage is useable...well now we are leaving the realm of science (what caused it) and entering the realm of art. You have to take of your technical hat, put on your artist hat and evaluate if it fits well in the piece you are composing. I'd bet that a lot of 'unusual' footage makes it into some films even though the unusualness wasn't planned.

But if it doesn't fit, it'll be like trying to pound a square peg in a round hole; you can include it but it will jar the senses when its displayed instead of perpetuating the feel of the piece you are creating. I'm having to mentally picture what it looks like, but I think you could probably place it between a dutch roll with the sun in the imagery and a rack focus from something close out to something distant.

Or a hundred other possibilities including some of the other footage you've already captured. "Feel the art...be the art." (Parody on a famous Caddy Shack line of dialogue)

Hello Patrick,

In theory you should be right as far as the filter not causing any negative effects, but the Neutral Density filter cuts down light without adding any color temperature change that doesn't mean that the filter is perfect and won't add other influences to your frame. In fact, these filters are not perfect and do add unwanted visual nuisances to your image. How much and how detectable they are depends largely on the quality of the filter.

However, the Canon XL series will cause this type of effect under certain conditions... in fact I believe it is even mentioned in the manual, or in an insert, or it could of been on their website... but I think it is right in the manual.

Bright sun, and zoomed in will cause a ghosting (and other unintentional effects) due to internal reflections or some such thing.

Now this could very well look like shimmering, especially if the heat aberration were to play a part in the overall effect.

Of course, it cold be a number of different things, and the use of the ND filter under certain conditions is certainly one of them.

Thank you Patrick and Anthony!

I think what I'll do is try shooting in the same conditions with Canon's internal ND filter on and off. You see, I didn't shoot all footage with it on. I tend not to use it too much......but, perhaps that's what did it. I've never seen it before. But, I usually shoot around 5pm at this time of year and we've been shooting in the morning lately to avoid the congestion of traffic, etc.

I may use that scene with the beautiful dandelions and create a fire in front of them or some such effect with Commotion Pro or AE or something else....we'll see.

Art is what I'm about Patrick...funny you should mention it. hummm.

I think the statement at the top of page 43 (directly under the bold title) may be what you are referring to:

While recording under bright conditions, the camcorder sets a small aperture value, and the picture may appear blurred. When you are using a lens with built-in ND filter, turn it on/off according to the screen display.

I read this as saying that the ND filter is available to overcome a small aperture blur, in other words, if its blurry in bright light, add the ND to clean it up.

Anthony, I know that no company is immune from a few lemons, but I find it hard to believe that Canon is going to spend so much R&D money to bring a fluorite lens to market and then put a cheap ND filter in the lens that distorts the image. My bet is still on 'optical distortion from convective heat' and not 'optical distortion from ND filter'.

I always shoot exteriors with an ND filter and I've never had that happen to me. Like patrick said, an ND filter will not introduce any anything that causes an optical effect, unless you have a damaged filter.

Jay

Hello Guys,

"While recording under bright conditions, the camcorder sets a small aperture value, and the picture may appear blurred. When you are using a lens with built-in ND filter, turn it on/off according to the screen display."

That's exactly right. This is nebulous to me, because I read it to mean something different than you did. I have experienced the problem though, which is why I interpreted it the way that I did. Removing the ND cleaned up the image (pretty cool effect though). Now under other conditions, this does not happen and the ND functions as expected.

It could very well be that their QC let some small sample slide through that were marginal, but I suspect it is within the engineering not QC. Depending on the angle of the sun to your subject and in relation to you and the subject, the intensity of the scene, etc all can factor in to cause unexpected results.

Just because an operator hasn't hit the exact conditions that cause this anomaly, doesn't mean that it doesn't exist. Keep shooting, you might experience it someday. I have only experienced it twice, but hay that's 2 more than you... right?

Like I said, the cause could be 100, or 1000, or an infinite amount of conditions and combinations, but this could be one of them.

BTW at the time this first happened to me my XL2 was still returnable, so I explored the problem with vigor... unfortunately I have since forgotten most of the results, but I kept the camera so I didn't believe it was a damaged component.

Peace

But Jay, if you had a damaged filter wouldn't it show up all the time? not only when you are close up?

I mentioned in another thread that the 20X lens had a flaw in it and Canon had to replace the whole camera because they won't have any 20X lens in stock until September. Tomorrow I will have my new XL2. It may be vaguely possible that the shimmering effect came from the flawed lens? At any rate, I plan to repeat the same conditions and see what happens. It sure looks like heat rising to me. And yes...it looks very cool!

Maybe, maybe not. The fact is a static filter--internal or external--faulty or not--will not (cannot) create any form of "motion" within an image, shimmering or otherwise.

The only condition I can image that something like that would happen is if the filter were not optically uniform--thick and thin spots. Then, as the camera was panned or titled (moved physically), the image might appear to have waves moving across or up and down as a result the "warped" surface of the filter.

Jay

Well this seemed to happen while the camera was still and moving.

Lucinda

While recording under bright conditions, the camcorder sets a small aperture value, and the picture may appear blurred. When you are using a lens with built-in ND filter, turn it on/off according to the screen display.

Hey all,

Regarding the above quote from the manual: I personally can't imagine when you would want to turn off your ND when shooting in bright light?? That's pretty much exactly when you're SUPPOSED to use them. Unless there is some weird camera bias regarding bright indoor vs. outdoor environments that the manual is trying to address? Seems totally weird to me.

I'd call Canon and ask them what's up? Go directly to the horses mouth I say. And BTW, does anybody know where that saying came from?

Sincerely,

Steph

Good Luck, after the long phone tree voyage, if you spoke to 10 techs, you'd have 10 different answers.

Any time you add a filter into your optical mix, you create the opportunity to experience reflections, which can look like ghosting.

"Go directly to the horses mouth I say. And BTW, does anybody know where that saying came from?"

I'll take a wild stab: Joyce Carey's novel: The Horse's Mouth?....

In a situation where everybody is running around attempting to get the best knowledge and tips on the outcome of a race, you can ask the owner, the stable lad or even the jockey. BUT, in a situation where many people have opinions, thoughts and predictions, there is but ONE real authority ONE individual within this "fog of information" and that is the actual Horse that will be running the race!

However, and here is the beauty of the English language and with a large dollop of irony, even the HORSE cannot determine the "outcome" of the race as it is a gamble. High stakes and even higher expectations. This situation pushes one to get even more informed information. Even more separation from an outcome we cannot ever hope to actually confirm with 100% certainty.

So, the concept of a horse ( from the horse's mouth )race truly, pictorially and succinctly illustrates the sometimes ludicrous steps we all go to get to "the" definitive answer we hunger after. We are all after certainty. The mouth of the animal is the nearest we are going to get. And guess what? Horses can't speak. That is the "other" irony. If it knew, it couldn't tell you anyway.

It's a bit like my attempt to explain this saying! HAH!

Grazie

Yeah, what he said :-)

And the one horse that could speak didn't race...of course, of course.

Lucinda, can you post a sample of what you shot, or send me a file to view?

Jay

Great quote in your sig. Jay! That Kevin Stav had SOME method with his acting.

I would really like to see the results too.

Grazie

Grazie, I hope we hear something from Lucinda.

By-the-way, are you sure that "G" in your names isn't supposed to be a "C"?

Jay

I'm here, I'm here......it's 58% humidity today and not at all what we're used to in the high desert country!

Yes, I can send a clip, just not sure where or how? I got my replacement XL2 this afternoon and spent the time putting in the new settings, or old settings. I hope this one will be ok. The lens has no flaws on the inside surface! that's a plus.

I do think tho' that the effect was caused by heat. I wasn't using an ND filter.

Anyway, Jay, just let me know how and where to send a very short clip of this and I'll do it.

Thanks for taking the time to look at this!

Lucinda

Lucinda!

Go to this thread (Blue Barn Pictures XL2 Presets Manager), download the FREE program Stephan Duke wrote and gave to Chris Hurd exclusively for DV Info members, install and upload/download/create/save all your presets in a matter of minutes instead of the afternoon.

In fact, if you go to this thread(XL2 Custom Preset Files), Chris posted a starter pack of presets collected from XL2 owners on this forum.

Then send us one of your favorite presets.

Ahhhh, Pat! Alas, I have a Mac! and don't know if some of this will work for me. Please advise. And, I have to go to LA a bit later today and can't get this done today, but tomorrow I could........

No, it won't work on a Mac.

Steve hasn't got the SDK for Macs from Canon yet. He's indicated he'll have it in Mac format shortly after Canon releases the SDK for Macs.

Sorry.