"Sensor Flares" - what's the truth?

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David G. Smith said:
Watch any movie from the '70s and you will see lens flares galore. Vilmos Zsigmond turned them into an art form, and won an Academy Award for Best Achievement in Cinematography for a movie where lens flares were added to special effects shots to increase their realism ("Close Encounters of the Third Kind").
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Sure. The only problem is that this is not a regular type of flare that is in question here. Even Barry agrees. It is a good idea to read the thread before replying, not just the last reply.
 
broughtonfilm said:
Sure. The only problem is that this is not a regular type of flare that is in question here. Even Barry agrees. It is a good idea to read the thread before replying, not just the last reply.
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I understand the issue. The response is about supposed "Flaws". They have been around for a long time.
 
broughtonfilm said:
My point was that because Barry made reference to a film camera in his article it proved that he was mixing different types of flares all together and that he was talking about flare issues in general, not this particular type and that it needed more attention.
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Yes, I did make mention of a film camera too. In addition. Not mixing anything, adding it all together.

I have absolutely researched the living hell out of this "sensor flare" issue. It does not need more attention. It is understood. It has been talked about and revealed. It has been thoroughly examined. I am not confused on the issue. We all know exactly what it is, why it happens, and why it is not, in fact, a big deal. It is just one more thing to be aware of. But it is not a big disaster, a design flaw, or anything of the sort. It is something that happens on all removable-lens video cameras, period end stop full disclosure been there done that. It is no worse on the AF100 than it is on the F3, it is simply how video cameras work, they all have protective coverings over their sensors and that causes a reflected flare to happen if you shoot an extremely, ridiculously overexposed bright light directly into the lens.

I brought the film camera into the discussion because on the ground glass I got the exact same kind of reflected flare. And I will be testing to verify if you can get the same flare actually on the film, which I think is possible because film itself can reflect light back. It may not be as crisply focused because the film is more matte than the sensor protection glass, but I have no doubt that in the exact same wildly-unrealistic and completely-impractical shooting scenarios that create this so-called sensor flare, that a film camera will exhibit similar flaring. Maybe not sharply-focused, but the same kind of thing. Again, we will see.

But the issue is understood, in fact at this point in time one could say that the situation is overstood. And it remains No Big Deal.
 
Barry_Green said:
it is simply how video cameras work, they all have protective coverings over their sensors and that causes a reflected flare to happen if you shoot an extremely, ridiculously overexposed bright light directly into the lens.

I brought the film camera into the discussion because on the ground glass I got the exact same kind of reflected flare. And I will be testing to verify if you can get the same flare actually on the film, which I think is possible because film itself can reflect light back. It may not be as crisply focused because the film is more matte than the sensor protection glass, but I have no doubt that in the exact same wildly-unrealistic and completely-impractical shooting scenarios that create this so-called sensor flare, that a film camera will exhibit similar flaring. Maybe not sharply-focused, but the same kind of thing. Again, we will see.

But the issue is understood, in fact at this point in time one could say that the situation is overstood. And it remains No Big Deal.
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Are candle flames, neon lights, traffic lights, fluorescent lights in the subway, practical lights etc. something that could be called "extremely, ridiculously overexposed bright light directly into the lens" ? Or if someone wanted to shoot a scene with such sources of light in them would they be shooting in "wildly-unrealistic and completely-impractical shooting scenarios" ?
 
The lights themselves are not the issue. It's how you expose them that determines whether it's an issue or not. With just the slightest bit of effort, you can make it be a non-issue. Have you looked at the practical shots that show NO issue? Getting there is well, well within the reach of this and all the other cameras.

If you want to shoot solely and only by candlelight, yes, actually, I would call that a wildly unrealistic and completely impractical shooting scenario. Wouldn't you? Now, if you shoot in candlelight but with actual real lighting, you're not going to see the "green ghost" because the relative level of illumination of the candle will be nowhere near what it takes to cause the issue. It's really very, very simple.

And besides, you CAN shoot solely and only by candlelight -- look at the F3 video, many many of the shots showed no issue, there was only one or two that showed it.

Furthermore, what is it that you propose? Every camera does it. Every interchangeable-lens camera has the same (minor) issue. So what are you asking for? Are you asking for every interchangeable-lens video camera ever designed to be redesigned? It's not gonna happen. They are made the way they're made for a reason. And besides, there's no reason for that to happen either. Just shoot reasonably. Just like we had to do with CCD vertical smears.
 
from my F3 with a Cooke Varotal Zoom.


The green dots that go in the opposite direction of the bokeh... flares from Christmas lights. Its normal, and it happens. Its a lens flare. This is the easter egg of shooting with 35mm glass. You get fun things like unexpected flares. The Cooke Panchros i have do not flare like this. Only the Varotal zoom, meaning the older lens doesn't have the rear coating that the newer lens does. Still glass usually doesnt have this coating. Modern cinema lenses do however, and thus are less susceptible to flares. Especially lenses that are "designed for digital" like the Optimo DP Rouge lenses.
 
What I do find odd is that I don't recall every seeing this in stills by a DSLR. But it does seem to be prevalent on many video, probably all, video cameras. Just don't know why it has been pointed out in DSLR stills. Or maybe it has and I just haven't heard of it yet.
 
It happens on my GH2, I can guarantee you that. In the thread when it was open, several people said they had the same effect happening on their DSLRs, and Philip Johnston posted a pic of it happening severely on his 5D.

I don't know if those were all video shots, or if any of them were stills... ?
 
Barry_Green said:
...
I don't know if those were all video shots, or if any of them were stills... ?
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Right, that's the thing, I don't recall ever hearing about this with stills. I've certainly seen it in DSLR video examples. Maybe it's just that no one would try to take a still picture in such foolish lighting conditions? IDK.

But I do know it's not an AF only thing by any means.
 
I think some people are disappointed when they compare their footage to some of the really great footage shot by the expert members of this forum. When their footage doesn't look just as good or better, a lot of people just blame it on the camera.

Yes, every camera or formate will have its limitations or negatives, but isn't it part of the cinematographer's job to be able to work around that?
 
Took off the protective filterSensor Flare

Took off the protective filterSensor Flare

Barry_Green said:
Recently there's been a lot of buzz and discussion over the concept of "sensor flares" and, particularly, the AF100. A blog article claims that there's a big problem with the AF100 that causes unacceptable flares, and that article has been tweeted and retweeted over and over, and it's stirring up a lot of fear, uncertainty, and doubt. Links to the original article were posted here on DVXUser, but the OP's behavior in the thread led to the thread being deleted (the reasons for which, the OP kindly made public by screenshotting the report). It wasn't the subject matter that was a concern, it was the tone and the FUD that was the problem. Here's some of the phraseology that caused concern... the original blogger used terms including:
"obvious Panasonic design flaw"
"a source of HUGE disappointment and a deal breaker"
"This issue is very severe and will ruin a lot of otherwise beautiful shots"
"Panasonic, go back to the drawing board!"
"AF100 camera is a prototype!"
"released without thorough testing"
"It hurts that we can't use it with any lenses!"
"it is a DESIGN FLAW of the camera."

Wow. Strong words. You'd think the AF100 was out there destroying shots and kicking puppies. How simply horrible it must be, right?

Well, let's find out. I looked into the issue. My method of testing was to use an LED light, because when the flare shows up, it reflects the individual LED's and makes it very easy to see. Now, first of all, in order to test for this, you have to shine a very bright light directly into the lens -- the wisdom of which is suspect, but hey, I'm game, let's try it...

Well, there it is, in all its glory. Clear as day, reflected flare. So, should we execute the AF100 right now and be done with it? Seems like our friend the blogger thinks we should (after all, he says it's a prototype and needs to go back to the drawing board). But I wonder... is this an issue that's strictly limited to the AF100?

I looked around to see what other interchangeable-lens cameras I have. Hmm, there's the GH2, let's try that. Blare the light directly into it, and ...

ACK! There it is again! Oh no ... maybe all Panasonics are haunted! How terrible this day is, to find out this horrible truth, isn't it?

What else do I have that has interchangeable lenses? Well, look, there's my Super16 film camera, let's try that. Obviously that won't have the issue, because it's not made by Panasonic... okay, let's shine the light in and ...

Well, what do you know. There it is. The exact same lens flare. The same "sensor flare" is happening on a 16mm film camera. (No video to show it, because the viewfinder opening on the camera is about 1/4" in diameter and I couldn't figure out how to film the ground glass through that opening). But I assure you it's there and looks very similar to the AF100/GH2.

Clearly, this is a DESIGN FLAW of all movie cameras, right? Perhaps my 1970's-era movie camera is a prototype and needs to be sent back to the drawing board?

Fortunately for us, there are other brands we can turn to. For example, the Sony F3. That's a digital cinema camera, brand new, and costs 3x as much as the AF100. With such a higher pricetag (and none of those "incompetent" Panasonic engineers working on it) it'll be free from such an issue, right?

Right?

Oops. Have a look at Hello World Communications' gorgeous candlelight test of the F3.
Beautiful, rich, lush cinematography but WHAT -- wait -- at 00:45 to 00:52, what's that on the left? Yep, there it is -- the dreaded green ghosts! And Timur Civan, an F3 owner, has confirmed for me that he's had it happen on his F3 too.

Well, heavens to betsy and with much wringing hands, whatever are we to do? It must be a conspiracy by all those big Japanese companies, trying to stick us with inferior designs and "obvious flaws". I guess we have no choice but to turn to Red to free us from the dreaded "sensor flare"... so let's go look at some Red Epic footage...
Stephan Gray posted that Red Epic low-light footage, shot at 2000 ISO, and ... uh-oh. What's that at 00:32-00:35? It can't be! But it is -- it's the dreaded "sensor flare!"

Oh no! Recalls and lawsuits, whatever are we to do? Well, at least there's one place we can turn to. The blogger said that the flares were practically nonexistent and much-better-controlled on his 7D, so we can always just go back to using a DSLR, right?

Er, not so fast. Hold your horses and hang onto your lunch. Philip Johnston of HD Warrior posted a (much-shorter) rebuttal to the original blogger's article, and showed just how much of a sensor flare his Canon 5D Mark II has:
Green-ghost.jpg


Interestingly Philip said that before he got this ghost shot on the 5D, he also shot the same thing with a bunch of other cameras, including a Sony MC50, Canon G12, Panasonic G2 and Sony HX5V. All of them delivered the same "Green Ghost" issue.

So -- where do we stand? Here's where we stand -- it happens. It is not an "AF100 problem" or a "DESIGN FLAW" or anything of the sort. It's an artifact that happens when you point a very bright overexposed light directly into the lens. Of course, this is old hat to any shooter who's been around a while; we all know that you're not supposed to purposely point a bright light directly into the lens or you'll get flares (including flares off the back element). For those who are panicking about it, it makes me wonder if they've never shot on a CCD camera? In the older days, there was another (far worse) reason to avoid a bright light directly in your shot, and that's the vertical smear that a CCD would exhibit:

300px-Vertical_smear.jpg

(hotlinked from www.wikipedia.org's article on CCD cameras).

That artifact was far more glaring and noticeable and inescapable than a ghosted reflection, but it taught us not to point the camera into extremely bright light sources (and not to point extremely bright light sources into the lens!) With CMOS, the vertical smear doesn't happen anymore, so now maybe people are more inclined to point directly at a bright light source? I don't know, but it's just common cameraman technique to not do that, or -- if you do decide to do that, you accept the consequences: lens flares.

Look -- here's the bottom line -- if you want to go out of your way to find a flaw in a camera, you can do that. Every camera, every lens, every recording format has limitations. Is it good to know those limitations? Sure -- that way you won't run into the problem. But EVERY camera has its limitations.

Is it helpful to find a limitation and call it a "DESIGN FLAW" and a "dealbreaker" and then re-tweet it to everyone on earth trying to stir up pandemonium and scare people from using a valid product? Of course not. To do so is the very definition of FUD -- it's spreading Fear, Uncertainty, and Doubt. We're not big fans of FUD here. We are focused on exploring what these cameras do and then teaching people what to do, and what not to do, to get the best results (and here's the lesson for today, folks -- don't go blaring a bright light directly into your lens!)

So let's turn to practical considerations -- can you actually shoot with an AF100, with a bright light in the shot, without getting "sensor flares"? Of Course You Can. Here's a little example shot I threw together, it's handheld, it's not meant to be beautiful, but it's a very low light scenario (shot at f/1.4, lit with one 55w fluorescent tube) and there's an incandescent lightbulb in the background that is so hotly exposed that it's clearly clipping.
See any horrible ghosts? Neither do I. It looks fine, just like it's supposed to. And if I was shooting this for real, I would have put a dimmer on the background light to bring it down so it wasn't clipping so ugly. And every bit that you bring that background light down, lessens the chance of it flaring and causing an issue. But even in this scenario, where it's obviously too bright and is clearly clipping hard, it still worked just fine.

PostScript: by the way, something can be absolutely true and still be FUD -- it's all in the way it's presented. For an excellent example, I would like to point you to the following warning site about the supposedly "dangerous chemical" dihydrogen monoxide:
http://www.dhmo.org



That website is for the Dihydrogen Monoxide Research Organization. Read the site. See if that chemical doesn't scare you to death. Here are some of the things they say about it:
  • Some call Dihydrogen Monoxide the "Invisible Killer"
  • Others think dihydrogen monoxide should be Banned
  • Dihydrogen Monoxide is linked to gun violence
  • Dihydrogen monoxide was found at every recent school shooting
  • Athletes use DIHYDROGEN MONOXIDE, or DHMO, to enhance performance
  • Dihydrogen Monoxide has been found in our rivers, lakes, oceans and streams
  • Dihydrogen Monoxide is a major component of acid rain
  • Thousands die each year after inhaling dihydrogen monoxide
  • Dihydrogen Monoxide can be deadly
Is any of it true? Yes, it's ALL true. 100% true. Should it be banned? Well, seeing as dihydrogen monoxide is ... well, it's two hydrogen, and one oxygen, hmm, that's H2O... yep, dihydrogen monoxide is WATER. Yes, if you inhale it you'll die. Yes it's found in our rivers, lakes, oceans and streams. Yes it's "invisible". Yes it's a major component of acid rain. Yes it's all true. But the way the dmho portrays it, it spreads fear, uncertainty, and doubt.

Ain't gotta be a lie, to be FUD. FUD is FUD.

Bottom line -- all these cameras work just fine, and if you blare a harsh light into them all of them will give reflected flares. So don't do that. Keep direct light from shining onto your lens (which is what flags and matteboxes are all about). And if you have to have a light shining directly into the lens, tone it down as much as you can, using ND gels and stopping the iris down -- the more overexposed the light is, the more likely it is to cause the flaring. Really, this is Camera Basics 101, but I guess with new tools comes new techniques and maybe not everyone knows these things, so it bears repeating.

We welcome constructive discussion and when an issue is found, we welcome a constructive and productive dialogue towards how to overcome or avoid such an issue. Thanks to all those over the years who have given of their time and talent to explain things to our membership.
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"I took off the screw on protective filter on my lens (Zeiss 35mm ZF) and the problem went away. I found it to be a reflection off the filter. Really wierd"
 
sstanek said:
"I took off the screw on protective filter on my lens (Zeiss 35mm ZF) and the problem went away. I found it to be a reflection off the filter. Really wierd"
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Yes that can definitely happen.

Also noted the flare on some of the FS100 footage and as Barry states its there on camera"S" and we just need to learn to deal with - same as we did with sensor streaks on CCD.
 
my af100 show this "issue" when I use my 24, 28 and 35mm nikon lenses, my 7d also have this green flare... sometimes a flare like that is wanted for dramatic reasons but not always. now with my 7d I can do nothing about it, but with the AF I just dial ND2 and the flare is gone
 
I have been a film guy for years before coming to digital media.
No film guy with half a brain shoots into a light source not expecting not to get flair lens and film!
If a nitpicker wants to find smoke all he has to do is light a match and he will find smoke.
Flair like this is not a issue with a real life pro shooter he knows his craft and knows better than to shoot into a light source. Someone has way too much time on his hands nitpicking gear that is just fine in a pros hands.
 
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