Serious flicker problem
 

I noticed this on Saturday while practicing at a bird snactuary/park (Flamingo gardens) in Davie, Fl. I was shooting in 60i hdv, at times in tv mode and also manual. I tilted up from the bottom of a huge tree, up to the sky , and back down. When I played back my foorage at home (Sony HDTV), I noticed a distinct flickering of light during that particular shot.
I did some shooting this afternoon to test out a stabilizer (multi rig pro) and went in to view some footage I had just shot. I did a wide shot of the grass in my front yard, and also a shot of some trees. Several shots had this same "flickering" or "shimmering" going on.
I figured I would troubleshoot the problem, so I tried to re create it under different conditions. I tried two presets, one stock factory and one custom. I duplicated the same shots in Tv mode, Tv exposure lock, and manual. I under and over exposed to see if that was the cause.( Btw, it's not visible in the vf). It didn't matter what I did, the camera still has the same problem. I didn't bother trying 30f,24f or SD, because ther IS a definated problem.
I'll try to contact Canon tommorrow, but wanted to check and see if anyone else has experienced the same thing.I ahven't seen this problem indoors, only out side. Unfortunately, I have a wedding on Sat, 2 cam hdv...
Bruce S. Yarock
www.yarock.com

Bruce: Are you shooting at -3 GAIN?.. If not, try that in identical circumstances.. I got TERRIBLE flickering, especially on foliage (with the XL2), until I figured that out (read post below)... Otherwise, I'm stymied...

Steve,
I've been shooting at 0, not -3. I'll try it tommorrow and see if there's any difference.Do you think that the 3 db would come in to play even when using the nd filter? Wouldn't the nd filter negate some of the gain?
Strangely, I never had that problem in the 1.5 years that I had my XL2 (or my GL1 before that). I'll let you know tommorrow. Dan keaton also suggested that I hook up my monitor outside under the same conditions, and see what happens. My monitor is sd (sony 9") and my HDTV is too big to drag outside.
Bruce S. yarock
www.yarock.com

Unfortunately the gain is a function of electronics and not exposure per se.. Canon, in an effort to make the camera seem more responsive in low light*, moved 0 GAIN to -3 GAIN... (*I'm guessing this was the motivation for an idiotic decision)...

I'm surprised you never had the problem with the XL2.. as we speak I'm frantically trying to edit around some footage I shot almost two years ago with my XL2... when the camera pans across trees there is an annoying sparkling... It is really bad in some situations, particularly on bright, clear sunny days with lots of contrast.. Then other times, it doesn't show up.. It's never a problem with soft lit scenes, interiors, or close-ups - it's wide exterior shots with lots of little details that need to get compressed...

but with -3 GAIN I never had the problem again.

Also, forgot to mention - dialing down DETAIL and/or dialing up CORING in the SETUP MENU is another sollution.. it takes some experimenting to get the right balance.. try -3 or -4 and +4 to +6.. but GAIN will have the greatest impact...

Steve,
I hope that's the problem. I have a wedding on Saturday, and if the H1 isn't working, we'll have to use my Sony FX1 as cam 1 and the MIGHTY canon HV10 as second camera! You should see what the HV10 looks like on top of a Bogen 503 head....like a mosquito humping a football. I can just imagine the spoiled bride pointing to the HV10 and asking "Who are you going to satisfy with THAT thing?"
Anyways, It's strange that nobody else has reported the same problem (unless I never saw the post). Thanks again,and I'll be trying -3 tommorrow.
Bruce S. Yarock

"Also, forgot to mention - dialing down DETAIL and/or dialing up CORING in the SETUP MENU is another sollution.. it takes some experimenting to get the right balance.. try -3 or -4 and +4 to +6.. but GAIN will have the greatest impact..."
I'll try the lower gain first, and then try this. Do you use a custom preset for this kind of bright, contratsy oudoors situation?
Bruce Yarock

Dear Bruce,

What shutter speed are you using? I assume that you would be using 1/60th, but we have not discussed it.

I also recommend using -3 gain whenever possible.

Bruce, call me if you wish to discuss this some more, I am at home.

Dear Bruce,

I have a recommendation.

Setup your camera so that the meta data (all of the settings and custom preset information) is recorded whenever you take a still photo with the XL H1.

Then, when you are testing, take a lot of stills. I recommend setting the still photo mode to the highest resolution.

Then we can go back and look at the still and read all of the setup information so we can trouble shoot your issues.

Do you use a custom preset for this kind of bright, contratsy oudoors situation?
Bruce Yarock[/QUOTE]

Well, yes I do - but I'm embarrassed to say that I usually forget to use it.. I often work fast and after many years of not having the option to change menu settings on the fly, it just isn't a habit I can easily adopt (old dog, you know).. But, as I said, the problem here seems to become a non-problem at -3... Good luck.

Dear Bruce,

Over the weekend you shot footage at Flamingo Groves.

Today you shot more footage.

You could not see any flicker either time in the viewfinder.

And, I assume that both times you saw the flicker on your Sony HDTV.

Have you captured your footage? Do you see the flicker on your computer monitor?

Try outputting an SD signal and feeding it to the Sony HDTV or another SD TV, and/or your SD field monitor. See if the output flickers.

I am wondering if the problem is in the camera, or possibility in the way you are viewing the footage (is the Sony HDTV the problem, or is it a setup issue)?

Dear Bruce,

I know that your shot of the trees involved camera movement, as you said that you tilted up to the sky.

What about yesterday? Were you panning or tilting when you saw the flickering? Were you on a tripod?

I recommend that you run a test with the camera mounted on a tripod, and have it locked down.

If you are panning or tilting and are using a high shutter speed, a strobing effect is normal deppending on the background. With a shutter speed of 1/60th of a second, a slow to moderate speed pan should not show any strobing, in my opinion.

Dan,
I was shooting hand held (but mot moving) 60i, shutter 1/60.As you suggested, I output the signal with the a/v out composite cable,thus viewing the footage in sd. hardly any of the flickering was then visible.
I don't remember ever seeing this problem on my Sony FX1, but I'm going to try the following today:
1- Reduce the gain to -3 on the H1.
2- Shoot the same test with all 3 cameras (H1,FX1 and HV10) and look at the footage of all three. I may also try with a tripod. But regardless, that flickering is a problem SOMEWHERE in the chain, and if it's in the camera, I have ro get to the bottom of it.
I'll keep you posted.
Bruce S. yarock
www.yarock.com

Bruce,

Any chance you can post a few seconds of footage that exhibits this problem so we can be sure what you are referring to? Obviously I have experience with that exact camera and never saw anything funky like this. I am really wondering if it is something going on with your playback monitor. It could be the camera but I'd like to check out the footage on my monitor to see what you are talking about.

Talk to you soon!

Marty

Marty,
Here's what I did today.
1- Shot a Minute wide shot in my front yard,basically the lawn (grass) in bright light. I tried the H1 first.Lowered the gain to -3, correct exposure, nd filter, manual mode, stock canon preset (yesterday I used a custom preset).
Results- the same flickering.
2- tried my canon HV10. Similar results.
3- same conditions, exposure etc.- tried my Sony FX1. VERY LITTLE OR NO FLICKERING.
But why is there a problem with the canon cams and not the Sony?
So then we-
4- Captured a minute to Premiere Pro(via Cineform), and watched it on the monitor (gateway FPD 1960 TFT LCD) and couldn't see any of the flickering light. So we changed the screen resolution to 1440 x 1080, and still couldn't see it on the computer monitor.
5- But then we exported the timeline back to the hdv camera, played it back on my Sony HDTV, and the problem was still there.
So to sum it up,both Canons,played back through the Sony hdtv, have the problem, but the FX1 doesn't. Could the issue be with the Sony TV? Also, we aren't sure why the problem isn't evident on the computer monitor (because it's not a hi def monitor?). I'd like to post a clip, but don't know how to do it with an hdv timeline.
I guess if I had access to another H1 and a real hdv monitor, I could do an ab test.
Any ideas?
Bruce S. Yarock

OK. One thing to keep in mind. The Sony TV is probably a 720P set. I could be wrong. So the resolution of the TV would normally be 1280x720. Your computer monitor is probably just as hi res.....maybe....maybe not. Both Canons are known to be higher res than the sony. It is possible that you are just feeding a signal that is higher res than the TV can really handle. Maybe.

Again....until I can see the exact problem it is hard for me to say. I have a 45" 1920x1080 display that looks great for the H1. I also have a 26" Tv that is 1280x720 that sometimes shows jagged edges and just doesn't do the H1 justice.

The good news is that if both the HV10 and the H1 are showing this there is probably not a defect in your camera. I'd lean towards the higher res of the Canons to be the culprit.....but we need more testing. Do the canons seems uber sharp in comparison?


Good Luck!

Marty,
The Sony tv is a KD-30XS955 FD Trinitron Vega.I think it's 1080i and 720p.Under "specifications" it says-
"Inputs/outputs
HDMI in-Video-1080i,720p,480p,480i"

Then it says "component Video input" 2(Y,Pb,Pr). I use the Canon cable via component in.
The canons are no way sharper thn the Fx1, at least to my eye.
Just as a test, I used the Sony and the H1 to also view the same footage through the Same tv.Here were the results:
Sony FX1-No flicker on the front lawn(that was encouraging), minimal on the side of house.(That was a little better than through the HV10, but still not right). Flicker at the bird sanctuary(Not encouraging).
Canon H1-pretty much the same.
At this point, I need to get with someone local with a pro HD monitor and play the footage back through all 3 cameras. Also,I was thinking of dubbing the obviously 'flickering" sections to another tape and sending it to you to see waht you think.
Bruce S. Yarock

The "flickering" is a combination of noise and aliasing. Noise can be reduced by decreasing the gain and shooting in even light (i.e. it's more visible in shadow where signal to noise ratio is worst). The aliasing is inherent in the design of any digital image sensor as has been discussed in this forum many times. Gain setting will have no effect on aliasing. There is, with HD, however, another place where aliasing can creep in and that is, as some have hinted here, with the display. The true 1920 x 1080 large screen TVs are just starting to enter the market now. Most of the old ones have appreciably lower resolutions and if the downconversion is not done right additional aliasing appears.

The XL-H1 seems to do a pretty good job of handling aliasing as opposed to the earlier XL series cameras. They may even have incorporated an optical antialiasing filter. This would cost some resolution but yield a reduction in the amount of aliasing recorded. So be sure to look at the video on a monitor that has 1920 x 1080 pixels i.e. one that does not require downsampling of the signal. All the aliasing will not be gone but it shouldn't be as noticeable as on some of the older large screen TV's which don't do the downsampling well.

Also watch some HD TV. You will see plenty of this flickering if you look for it. I was just watching some sportscaster the other night who must have bought his jacked from Moire Fashions. I was surprised that the producers let him wear it (though my set isn't 1920 in the H direction it does a pretty good job of downrezzing but that might have caused it).

Duplicate post deleted

A.J.
What about a decent HD monitor? I was thinking of going to a local rental place and watching the clips through a real hd monitor.What should I ask them...if they have one that's 1920x 1080?
Thanks
Bruce S. yarock
www.yarock.com

Dear Bruce,

I have researched your very nice Sony HD CRT television.

Sony does not specify what the native resolution is for your television, as is typical for most CRT based HDTV's.

While yours is a very nice set, I do not believe that it is "Full HD", ie 1920 x 1080. I say this to indicate that the flicker problem may actually be in your set and not your camera.

A test with a 1080p set, other than any CRT may determine if there is flicker in you footage. I do not know of any 1080p CRT's, at least in the normal price range.

Take your camera to best buy and hop on one of the 1080p lcd displays. tell them your thinking about buying a new one or somehting but you want to see how ti looks. They won't care, heck they'd probably be happy to see something new on one of those screens. if you still have the issue report back.

Nick,
Good idea. I'll try tommorrow.
Bruce Yarock
www.yarock.com

Yes, an HD monitor should do if it has 1920 x 1080 resolution or good downconversion circuitry (which a good monitor should). An LCD or plasma TV or projector should do as well. It was 6 months ago when I looked but at that time Westinghouse had just put a TV on the market with 1920 x 1080. There are doubtless others out there by now. Note that the set doesn't have to be capable of 1080p as the camera will put out 1080i even if you have shot in F mode (the fields will be aligned though so you will see 1080F).

A.J.
I shot the footage in 60i. I'm going to try Best Buy tommorrow and se if they have a set I can view through.If not,I know someone who has an HD monitor (don't know the specs) which I can try Tuesday.
thanks
Bruce S. yarock
www.yarock.com

Another thought about the sharpness between the H1 and FX1. If you have only ever viewed the footage on a TV that is capable of 720P then you have essentially limited the viewable resolution of both cameras. Even a TV that accepts 1080i might only be a 720 display and it performs a downconversion. My HD monitor that is hooked up to my PC is a CRT and it accepts 1080i and 720P but the actual resolution is only 1280x720. On this TV the HVX and the H1 look similar in resolution...with a minor edge going to the H1. However on my main TV which is a 45" 1920x1080 display, the H1 looks much better.

What I am getting at is that the FX1 may look every bit as sharp as the H1 on a 1280ish display but in reality both are being held back. The H1 may have more res and that could cause issues with the downsampling of the television in question, wherer the FX1 doesn't.

Regardless I think you can breathe a sigh of relief that your camera is probably not defective. If both the HV10 and the H1 show this issue it is probably a design thing and you just need to figure it out so you can work around it.

The HV10 actually has a 1920x1080 cmos sensor so it might exhibit this issue more....have you noticed a difference between the H1 and hte HV10?

"sigh of relief".
I played the footage through my parents new 46''Sony Brava, which is higher resolution than my Sony Vega HDTV, but not 1920x1080. I saw No...that's No flickering at all. So I guess the problem lies in my Sony Vega hdtv. Better there than in my H1.
Thanks, everybody.
Bruce Yarock
www.yarock.com